Phosphorus-From Discovery to Commodity

Indian Journal of Chemical Technology Vol. 12, January 2005, pp. 108-122

Phosphorus-From discovery to commodity

Jaime Wisniak* Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel 84105 Phosphorus is nearly the most widely and evenly distributed element on the surface of the earth, and probably the most subdivided. From a laboratory curiosity in the seventeeth century, it became recognized as a fundamental element of life and a large chemical commodity, improving agriculture and industry like very few other discoveries by men have done.

Discovery of phosphorus nor the phenomenon was really new. Organic Mankind has been aware of luminiscent phosphorescent materials were known to Aristotle, phenomena for thousands of years; they are and a lithophosphorus was the subject of a book mentioned in different mythology and in the Bible. published in 1640, based on a discovery made by a Glowworms and fireflies, and the luminescent shoemaker, Vicenzo Casciarol, on Mons Padernus, organisms in sea water or on decaying fish and wood near Bologna in 16303. Casciarol claimed that the were long familiar sights and attracted the curiosity of stone was so heavy that he thought it contained a men. The Greeks called the planet Venus by the name heavy metal and that after it had been calcined in Phosphorus (morning star, from the Greek φϖζ = charcoal fire and cooled, it glowed in the darkness light + φερω = to bear), because it was visible before with a reddish light. The stone was called sunrise and after sundown. Venus took the name litheosphorus and also Bologna stone or lapis phosphorus in the morning and Hesperus in the bononiensis. Johann Gotfried Leonhardi (1746-1823) evening (hespera = afternoon, occident). Homer says: quotes a book of 1689 in which the author, Kletwich, "Phosphorus, the son of Heavens and Dawn leaves in claims that his phosphorus had already been known to the morning the Ocean river and by elevating its Jean Fernelius (1497-1558), the court physician of sacred forehead announces to the Earth the proximity King Henri II of France (1519-1559). In his book of the divine light, holds in his hand a torch and goes about the history of chemistry Ferdinand Hoefer flying before the chariot of Dawn". Pliny writes: "The (1811-1878) tells about finding in the publication fish on this account called the lamp fish rises to the “Ordinatio Alchid Bechil Saraceni Philosophi” the surface of the sea, and on calm nights gives a light description of a process in which urine was distilled with its fiery tongue, which puts out from his mouth" with clay and carbonaceous material, resulting in a 4 1a, and then "Glow worms shine like fires at night product named escarboucle . owing to the colour of their sides and loins, now A new variety of luminescent stones was giving a flash of light by opening their wings and now accidentally discovered in 1674 by Christian Adolph darkened by closing them"1b. Baldouin (1632-1682), at Grosshain, Saxony. It In the tenth century, Japanese used as decroative resulted from the strong ignition of the residue, material the luminescence of lacs that they prepared obtained by evaporating a solution of chalk in nitric from oyster shells. At the beginning of the eighteenth acid. Baldouin was a member of the Imperial century, appeared the first synthetic luminescent Academy of Sciences, and as such received the material in Europe, the stone of Bologna, also called cognomen Hermes. He therefore named his light sponge, and made of barium suphide. These preparation Phosphorus Hermeticus or, alternatively artificial products, which after exposure released the Magnes Luminaris because it attracted light like a absorbed light when placed in the dark arouse much magnet attracts iron particles. The name was changed excitement from the time of their discovery at the later to Baldwin's phosphorus. In 1675 Badouin beginning of the seventeenth century. issued a booklet describing this phosphor, but did not According to Farber2, neither the name phosphorus disclose the method of preparation5,6. The procedure ______was published first by Kunckel in his Laboratorium 7-9 *E-mail: [email protected] Chymicum . EDUCATOR 109

In the year 1669, phosphorus was accidentally that contributed many new facts to chemistry. He discovered in human urine as “a dark, unctuous, discovered mercury fulminate and nitric ester, and is daubing mass” by Hennig Brandt, a merchant and best known for his work on ruby glass and on alchemist of Hamburg, while searching for a liquid fulminate. In the third part of his book Laboratorium capable of transmuting silver into gold. Brandt was a Chymicum7 he gives an account of ruby glass and soldier in his youth, and it is said that later he became phosphorus, the two chemical discoveries which he “an uncouth physician who knew not a word of considers to be the most important of the century. In a Latin”10. In spite of this deficiency he married a following publication (1680) Kunckel described the wealthy wife, but after her death he lost the inherited properties of phosphorus more fully but did not money. In an attempt to regain his list financial provide details about the method of its preparation. standing, he was lured by the spell of alchemy to He had first obtained phosphorus in the form of a search for gold. His experiments made in 1669 led to black soap, which glowed in spots and did not shine a white, waxy substance that glowed so enchantingly continuously. In his own words: "A little of this soap in the dark. When his alchemical experiments ground up in clear water and shaken about gives a revealed the light-giving element Brandt called it cold very pleasant light, and some of the particles which fire (kaltes feuer). Brandt kept secret his method of remain attached to the glass above the water flash and obtaining phosphorus, but the news of the amazing twinkle like little stars… This soap has the property discovery soon spread throughout Germany11. that gunpowder put with it and merely left in the Wilhelm Homberg (1652-1715) described Brandt's warmth of the sun, takes fire of its own accord…A discovery in the following manner: Brand, “a Man man can write on paper with it, and if he has a piece little known, of low birth, with a bizarre and only as large as the head of a small pin, he can make mysterious nature in all he did, found this luminous unbelievable light back and forth with it on the paper matter while searching for something else. He was a until the little grain is worn off and cannot be seen... I glassmaker by profession, but he had abandoned it in have something on still another subject; a thing which order to be free for the pursuit of the philosophical is so subtle that, if it is allowed to warm up on the stone with which he was engrossed. Having put it into bare hand, it forthwith inflames and gives a furious his mind that the secret of the philosophical stone fire. The residuum, which is left behind, shows an consisted in the preparation of urine, this man worked orange colour and flashes and shines like the in all kinds of manners and for a long time without Smegma". The last quoted passage appears to contain finding anything. Finally he found in the recopied a the earliest known reference to the red modification of 13 luminant matter that has since been called phosphorus . phosphorus. He showed it to some of his friends, After visiting with Brandt, Kunckel wrote among them Mister Kunkel”. Homberg considered immediately to his friend, Johann Daniel Krafft phosphorus to consist of phlogiston united with an (1624-1697), a commercial agent from Saxony acid so that during combustion the phlogiston Dresden. Krafft, without replying to Kunckel’s letter, escaped, and the acid remained as a residue12. left immediately for Hamburg and bought the secret Johann Kunckel (1630-1702), a contemporary of from Brandt for 200 (thalers) dollars, Brandt, was the son of an alchemist in the court of the Although Kunckel did not describe the method for Duke of Holstein. In his youth he studied pharmacy, the preparation of his phosphorus, it seems that he glass-making, and assaying; worked in the Dresden accomplished it, as did other chemists after him, by laboratory of John George II, Elector of Saxony; evaporating putrid urine to the consistency of a syrup, taught chemistry in the medical school at Wittenberg mixing it with sand or brick dust, and distilling at a and later managed the glass-works in Benlin high temperature from a fortified (coated with clay) belonging to Frederick William, the Elector of retort, the beak of which delivered under water in the Brandenburg. According to Weeks11 his last years receiver. The silicic acid of the sand or brick dust were spent at the service of King Charles XI of liberated phosphoric acid from the phosphates of the Sweden, who conferred on him the titles Baron von urine and this was reduced by the carbonaceous Löwenstern and Counselor of Metals. Kunkel was one material, which was present13. According to of the most competent chemists of the seventeenth Homberg, Kunckel’s process was essentially as century. He was an exceptionally able experimenter follows: Fresh urine was evaporated nearly to 110 INDIAN J. CHEM. TECHNOL., JANUARY 2005

dryness, after which the black residue was allowed to subsequently exhibited in Hamburg was Baldouin’s putrefy in a cellar for several months. This material phosphorus, a phosphorescent form of calcium nitrate was heated, gently at first and then strongly, with that had been prepared by distiling a solution of chalk twice its weight of sand, in a retort leading to a in nitric acid15. receiver containing water. After the volatile and oily In 1670 Robert Boyle (1627-1691) brought over constituents had distilled over, the phosphorus begun from Germany a young man named Ambrose Godfrey to settle out in the receiver as a white, waxy solid. To Hanckwitz (1660-1741) to assist him in his chemical prevent fires and explosions, it was necessary to experiments. One of Hanckwitz's first assignments remove the flame as soon as the phosphorus began to was to prepare phosphorus, which he did promtply appear, and to keep the receiver closed until it became and in ounce quantity and years later published the cold. This was the part of the process which Kunckel pertinent details16. Boyle's basic procedure consisted thought too dangerous to reveal to the public, giving in heating sodium phosphite with sand: as his reason the fear that dangerous accidents with phosphorus might become frequent. Kunkel not only 4NaPO+ 2SiO+→ 10C 2Na SiO + 10CO + P … (1) prepared phosphorus, but also cast it in molds, which 32 23 4 he exhibited to the Courts of Saxony and Boyle called the material icy noctiluca (cold light) Brandenburg, although it was not a very delicate 17,18 agreeable exhibition, “because unctuous and daubing and examined its properties in a systematic way . oyliness was not yet accurately separated from it, and He proved that the dependence of glow on air supply without doubt, it was very stinking and therefore and quenching it in vacuum or by turpentine. He also unpleasant”14. He also introduced it as a medicine, discovered phosphoric acid as the product of recommending pills of phosphorus for internal use, oxidation. After speaking of three sorts of phosphorus and coated them with gold and silver, evidently by he says: “The other is Phosphorus Fulgurans, which is allowing the pills to stand in contact with solutions of a matter, made both in a liquid and dry form, and not these metals. According to Kunckel these pills would only shineth in the dark and communicates a sudden save a person from apoplexy or of other sudden light to such bodies as it is rubbed upon, but being sickness; they counteracted all noxious and poisoned included in a glass vessel, well closed, doth now and airs and were an antidote against the pestilential then fulgurate, and sometimes also raise itself as it poison. The pills caused no vomiting and were waves of light. Differing from the Balduinian inconvenience and acted in a mysterious manner13. stone, which is to be exposed to some shining body, Kunckel discussed the medical properties and uses of as the day, the sun, the fire, or some lighted candle, to phosphorus in his book Treatise of the Phosphorus receive light from these, whereas this fulgurating Mirabilis, and its Wonderful Shinning Pills8. As a substance carries its light always with it, and when result of this discovery the Duke Johann Friedrich of put in a dark place presently shews the same. Of Hannover paid him an annual pension for the rest of which we have this further assurance given us, that a his life. little portion of it having been kept two whole years hath not yet lost its power of shining. So that it is According to Thomas Thomson (1773-1852) believed if a considerable big piece were prepared of Homberg purchased Kunckel’s secret of making ir, it would serve for a perpetual or, at least, a very phosphorus by giving him in exchange the ingenious long lasting light”14. barometer invented by Otto von Guericke (1602- In 1680, Boyle described his method of preparation 1686) in which a little man comes to the door of his in a paper deposited with the Royal Society, but not house in dry weather and discreetly retires within as 19 11 published until 1682, after his death : "There as taken soon as the air becomes moist . a considerable quantity of man's urine, and of this a In 1902 Hermann Peters (1847-1920), a famous good part.. had been well digested before it was used. German historian of chemistry and pharmacy, made a Then this liquor was distilled...till the remaining thorough study of the autograph letters of Brand, substace was...a somewhat thick syrup. It Krafft, Kunckel, Homberg, Gottfried Wilhem Leibniz was...incorporated with thrice its weight of white (1646-1716), and others and found that all agreed that sand...a naked fire was was administered for five or phosphorus was originally discovered by Henning six hours...By this means there came over good store Brandt. The luminous substance which Kunckel of white fumes... they were after succeeded by EDUCATOR 111

another sort that seemed in the receiver to give a faint formed that look like very fine snow and adhere to the bluewish light, almost like that of little burning walls of the vessel, (d) during the initial stages of matches dipped in sulphur. And last of all..passed combustion there is a considerable expansion of the another substance that was judged more ponderous air due to the heat generated by the combustion, (e) that the former... whence being taken out appeared by this same air experiments a considerable contraction several effects and other phenomena to be such a kind once the vessel cools down, to about 5/6 of the of substance as we desired and expected". original volume. (f) weighing the flakes indicates that Until 1737, the method of manufacturing their weight is substantially higher than that of the phosphorus remained a secret, but in that year a original weight of phosphorus. The increase in weight stranger in Paris offered to sell the secret process to is exactly proportional to the amount of air absorbed, the Académie des Sciences. After accepting the offer, (g) air remaining after combustion is lighter than the the French government appointed Jean Hellot (1685- original and does not support breathing, nor 1765), chairman of a committee to study the process, combustion or inflammation of bodies. and his detailed report made the process accessible to From these results, Lavosier came to the conclusion all chemists11,20,21. that air is composed of two materials, one quart of an In his researches on phosphorus, made between eminently respirable substance and three quarts of 1743 and 1746, Andreas Sigismund Marggraf (1709- another non-breathable (mephitic) air. Similar results 1782) found the new substance in edible plant seeds, were obtained when burning sulphur instead of and he concluded that it enters the human system phosphorus. During combustion phosphorus reacted only through the plant food, to be excreted later in the with the breathable portion of air without having any urine. He wrote: “My thoughts about the unexpected action on the mephitic component, which could be generation of light and fire out of water, fine earth, considered as a passive medium. In addition, phosphoric and phlogiston I reserve to describe at a later time.” acid and sulphuric acid seem to be composed of more or Marggraf did not convince all the chemists with his less fifty percent of their weight of breathable air. reasoning. For example, in 1789 Pierre-Joseph Eventually, Lavoisier's results on combustion lead to Macquer (1718-1784) wrote: “There are some who, the demise of the phlogiston theory. even at this time, hold that the phosphorical acid One of the most famous alchemical paintings of the generates itself in the animals and who consider this eighteenth century is the Discovery of Phosphorus done to be the animalistic acid2,22.” in 1771 by the English painter Joseph Wright (1734- The discovery of phosphorus, followed soon after 1797) (Fig. 1), who was fond of putting a strong source the discovery of the induced phosphorescence of of light in a central part of his composition and tracing certain calcium salts had an enormous effect on the highlights and shadows created in this way. The contemporay chemists. The new substance shone painting captures de wonder of the discovery, but continuously in the dark, inflamed on slight exaggerates the intensity of the light it emits. provocation, burned with a flame extraordinarily brilliant, and wasted away entirely unless kept under Phosphorus sources water. Its important role in biological processes makes The similarity of results in the burning of sulphur phosphorus one of the most dispersed elements in and of phosphorus caught Antoine-Laurent nature. It is not found free and almost always occurs Lavoisier’s (1743-1794) attention. In his first volume in the fully oxidized state (+5) in the form of of Opuscules Physiques et Chimiques (1774) he orthophosphates. These are very widespread; in the devoted 22 pages to his experiments on phosphorus23. earth, in rocks, on the ocean floor, in all living cells In a later publication24 (1777) he exposed his and in the bones of animals, in most foods, and in experiments and results on the combustion of many man-made materials. Phosphorus is the eleventh Kunckel’s phosphorus: (a) that it is possible to burn most abundant element occurring in almost all only a certain amount of phosphorus for a given volcanic and sedimentary rocks. Most of the amount of air, (b) once the combustion has ended it phosphorus in the earth’s crust (about 0.1% of it) extinguishes without being possible to relight by any occurs as phosphate rock present in the volcanic means, (c) during combustion a large amount of eruptions during the period of earth formation. flowers or white flakes of phosphoric acid (P2O5) are Erosion by water of the deposits of volcanic 112 INDIAN J. CHEM. TECHNOL., JANUARY 2005

phosphate), which is cryptocrystalline. Crystalline apatite is of inorganic origin while phosphorite is the remains of animal bones. The largest reserve of crystalline apatite is in the Kola Peninsula, near Murmansk, Russia, and the largest reserves of phosphorite in the U. S. are in Idaho and Wyoming. In addition to the sedimentary phosphate deposits, there are some igneous rocks that are also rich in phosphate minerals25. The sedimentary phosphate deposits represent by far the largest quantity of phosphate rock both as regards to size of the reserves and the amount extracted. Because they mainly originate from animal remains from earlier geological epochs, they also contain sand, silicates, carbonates and organic carbonates26. Phosphate rock is formed in oceans as phosphorite. It is deposited in extensive layers that cover very large areas. Sedimentary phosphorite is believed to have originated from this widely distributed apatite. Weathering and leaching processes led to the transfer of the phosphate to the soil, to rivers, and to the oceans, where it was concentrated in by chemical Fig. 1⎯The Discovery of Phosphorus, painting (1771) by Joseph reactions, shells, bones, and marine organisms, which Wright (1734-1797). were deposited in the ocean floor. Subsequent uplift and other geological movement led to these phosphates, followed by assimilation by prehistoric accumulations becoming dry-land deposits. The total plants, introduced it in the biological mechanisms. amount of phosphorus dissolved as phosphate in the Today, we know that phosphate groups are an world’s oceans has been estimated of the order of 1012 indispensable part of the structure of DNA and play a tons27. vital role in metabolism and transfer of biological energy. It is an essential element for plant and animal Phosphorus-rich sediments alternate with other nutrition as is consumed primarily as a principal sediments (interstratified), they usually have very few component of nitrogen-phosphorus-potassium fossils; however, deposits in Florida and North fertilizers that are used on food crops throught the Carolina (United States) contain a large amount of world. It is present in the bony tissues and in the teeth marine fossils. Some geologists believe that the as hydroxyapatite, it is an important agricultural formation of these phosphorus layers occur under a fertilizer, a component of matches, and an ingredient very special condition in which no other type of in pyrotechnic applications25. sediment is present. In addition, it is believed that Phosphorus can be found in almost 300 different phosphorus-rich rock is deposited in a body of water minerals, but only the apatite series has an important in which there is no oxygen (anaerobic environment). role as phosphorus source (the generic name for a Deep-sea exploration of the world’s oceans has rock containing apatite is phosphate rock). Nearly all revealed that there are large deposits of phosphates on igneous rocks contain some phosphate, with most of it the continental shelf and on seamounts in the Atlantic in the form of apatite. The apatite series is represented and Pacific Oceans. Recovering these deposits, however, is still too expensive, so they remain by the formula for a unitary cell Ca10(PO4)6 (F, Cl or untouched for now. OH)2 and its main representatives are hydroxyapatite and fluorapatite. The greatest phosphate deposits in Apatite is virtually the only mineral used in the Nature are composed mainly by fluorapatite, having a industry as a source of phosphorus and it is mined in hardness 5 (medium hard) and density 3.15-3.20 the northern part of Africa (particularly Morocco and g/cm3. It occurs in two principal structures, crystalline Tunisia) and in the United States (Florida, North apatite, and phosphorite (a form of calcium Carolina, Utah, and Idaho). In 2002 the mines in the EDUCATOR 113

Florida and North Carolina region accounted for 86% Table 1⎯Phosphate rock reserves and reserve life (103 metric of U.S. domestic production of phosphate rock. In the tons)25 same year Florida accounted for more than 75% of domestic production and about 20% of world Reserves Reserve life (106 tons) (years) production, which was greater than Morocco, the world second largest producer (Table 1). Brazil 364 75 Over three-quarters of the world phosphate rock is China 1,102 46 converted into phosphoric acid by a wet process. India 1,730 1,262 Iraq 1,000 1,000 Phosphate rock is mined, beneficiated, and either Israel 198 44 solubilized to produce wet-process phosphoric acid or Jordan 992 156 smelted to produce elemental phosphoric acid. Morocco 628 1,248 Phosphoric acid is reacted with phosphate rock to Russia 220 20 produce the fertilizer triple phosphate or with Senegal 50 33 South Africa 1,653 524 anhydrous ammonia to produce the ammonium Syria 110 56 phosphate fertilizers. Elemental phosphorus is the Togo 33 17 base for furnace-grade phosphoric acid, phosphorus Tunisia 100 129 pentasulfide, phosphorus pentoxide, and phosphorus United States 1,102 25 Others 1,322 110 trichloride. Approximately 90% of phosphate rock production is used for fertilizers and animal feed or in the presence of any gas that did not react with supplement and the balance for industrial chemicals; phosphorus. Since none of the available theories was less than 5% is used to make commercial phosphorus able to explain this phenomenon Schröetter decide to compounds25. study it in more detail. The first step was to see if the Animal bones are still used after conversion to presence of oxygen was necessary for the reaction. bone meal by grinding, or to bone ash by calcining. When phosphorus absolutely dry and deprived of any Such products are rich in calcium phosphates and are contact with oxygen, was subject to the action of light used as fertilizers or as supplements to animal it turned almost immediately to red, the foodstuffs27. transformation being faster if the light was more Properties intense and at temperatures atmospheric or above. When phosphorus was discovered, nearly three Lowering the temperature to 287 K resulted in a much centuries ago, it was considered a miraculous thing. slower reaction. The same results were obtained if The excitement about Phosphurs igneus, Boyle’s Icy phosphorus was in contact with carbon dioxide, Noctiluca18 was slowly replaced by, or converted into nitrogen, or hydrogen. All these observations were a chemical research2. clear proof that oxygen was not necessary for the Today we know that phosphorus occurs in three reaction. Heating phosphorus in the absence of light main allotropic forms: white, red, and black. These led to a change in colour from white to carmin only at allotropes, which can be intercorverted, represent 500 K, it thickened slowly, its colour intensified, and successively more dense and chemically less reactive finally became opaque. This was a slow forms, with black being the thermodinamic most transformation. Keeping the phosphorus at 513-553 K stable form. Other forms of solid phosphorus are for 48-60 h, led to the deposition of a more or less derived from these three main allotropes. Only white thick solid phase of amorphous phosphorus in the and red phosphorus are of industrial importance26. bottom of the vessel, while the upper layer remained Before describing the properties of these forms it is of ordinary phosphorus. The latter could be separated historical interest to understand how they were easily by adding to the charge water heated to 323- discovered. In this relation the most important research is 343 K, which resulted in the melting of the upper that done in 1845 by Anton Schrötter (1802-1875) layer. In general, the temperature at which phosphorus because it led to the fast development of the match changed to amorphous depended on the temperature, industry28. the time of reaction, and the action of light. The According to Schrötter, it was known for a long simultaneous action of light and higher temperatures time that phosphorus exposed to the action of light made if faster. Hence, according to Schrötter, the turned red, a transformation that took place in vacuum concurrent action of light and heat resulted in the 114 INDIAN J. CHEM. TECHNOL., JANUARY 2005

allotropic transformation of phosphorus, as proved by only at higher temperatures and in the gas phase. This the fact that the new form of phosphorus reacted in form is called white phosphorus (it is actually the same way as white phosphorus, or that it colourless) and is the one that phosphorus usually converted back to white phosphorus by heating at takes when it is reduced to the pure element. temperatures about 523 K in an inert gas. The two Generally it has a yellow tinge due to small amounts forms could be easily separated with carbon disulfide, of red phosphorus, so it is sometimes called yellow a solvent that dissolved only white phosphorus. phosphorus. The white form is the most volatile and Schrötter separated red phosphorus and measured reactive of the solid modifications and exists in at many of its properties. The most important result was least two allotropic forms. The α form occurs under that it could be kept in contact with air without ordinary conditions of temperature and pressure and alteration. It was insoluble in carbon disulphide, his formed on condensation of phosphorus vapours alcohol, ether, PCl3, turpentine, and naphtha. Heating under water. It is a transparent, waxy mass with a 3 it under a liquid caused the colour to change from red density of 1.83 g/cm . It easily forms tetrahedral P4 to strong violet. It reacted with chlorine to produce molecules (the edge of the tetrahedron is 0.221 nm) PCl3 and PCl5 at room temperature, an exothermic that exist in the gas phase and also as a waxy solid reaction but without light effects. It was attacked by and viscous liquid, melting at 317.3 K and boiling at aqueous chlorine forming HCl and phosphoric acid, 553.7 K. At 195.4 K the α form changes to a β one sulphuric acid, diluted or concentrated, did not react having a density of 1.88 g/cm3. The crystal habit of at room temperature but did at its boiling temperature, the α form is cubic while that of β is hexagonal. releasing SO2. The amorphous phosphorus was easily Above 473 K yellow phosphorus changes into red attacked by nitric acid with release of gases. Mixed phosphorus. A cold greenish phosphorescent glow is with potassium chlorate it detonated violently, associated with this allotrope, due to a slow oxidation producing light. of the vapour emitted. Schrötter concluded that the chemical reactivity of White phosphorus is non-conductor, virtually amorphous phosphorus was weaker that that of ordinary insoluble in water and can be stored, fused, and phosphorus; it combined with release of light, but less transported quite safely under an aqueous layer. It will energetically than ordinary phosphorus. It combined with not ignite under water unless oxygen is bubbled in. It oxygen, by friction or heat, to produce a large number of is soluble in many liquids, especially in PCl , PBr , oxygenated derivatives, with release of light. All these 3 3 CS2, liquefied ammonia and liquefied sulphur dioxide, characteristics, including low its hygroscopicity and and also in organic solvents such as benzene and lesser flammability suggested its possible use in the diethyl ether. At elevated temperatures and pressures manufacture of matches and percussion weapons. The water vapour will react with white phosphorus to only disadvantage was the difficulty in preparing it in a form various products such as phosphine, phosphorus large-scale. In due time his prediction became true: In acid, and P O . Sweden the Lundström brothers, developed and sold a 2 5 safety match in which white phosphorus was replaced by White phosphorus is very stable and highly red phosphorus, the phosphorus being confined to a strip deliquescent; it will extract water even from ethanol on the box and the oxidizer was used to tip the matches. to form ethylene and from sulphuric acid to form SO3, Such safety matches could only be ignited by striking on hence it is an excellent drying agent. It oxidizes the box, while earlier matches could be struck anywhere spontaneously in air (autoignition temperature of on a rough surface. 303.3 K) often bursting into flame; it will burn in both In 1856, the Académie des Sciences awarded Schrötter oxygen and carbon dioxide yielding copious the Montyon Prize, designed to acknowledge the services quantities of white smoke (P2O5) that has the highest of those, which had made notable contributions to total obscuring power of any smoke. In a restricted industrial hygiene conditions28. supply of oxygen, lower oxides are produced. The The different allotropic forms have the following white smoke may be irritating but is not considered to characteristics: be toxic. It was widely used in World War I in grenades and trench mortar rounds to screen troop (a) White phosphorus movements. Most military smokes are now of other Presently, we know that phosphorus can form a types, often coloured with dyes. Water will extinguish diatomic molecule P2 with a triple bond like N2, but white phosphorus temporarily, but as soon as the EDUCATOR 115

phosphorus has access to air, it will start burning at low temperature. Turpentine was eliminated again. White phosphorus precipitates copper and lead without causing major health disorders31. from their solutions at ordinary temperatures and reacts with metals to form phosphides at high (b) Red phosphorus temperatures30. This allotropic form includes many crystalline or White phosphorus is physiologically a strong amorphous forms with varying depths of colour. The 3 poison and as little as 50 mg can be fatal. Any human densities are in the range 2.0 to 2.4 g/cm and the exposure to white phosphorus may cause several melting points between 858 and 883 K. Red thermal burns to the skin and eyes. Its vapour can phosphorus, as ordinarily prepared, is amorphous or cause severe lung irritation, followed by a build-up of microcrystalline. Its colour, density and other physical fluid in the lungs. Continuous long-term inhalation of properties, as well as its chemical activity, are white phosphorus vapour (> 0.1 mg/m3) may result in governed by the conditions under which it is formed. bone loss to the jawbone structure causing loosening All the forms of red phosphorus appear to be made up of teeth and swelling of the jaw. This condition is of P4 molecules polymerized in various degrees. commonly referred to as phossy jaw 30. Above 473 K, yellow phosphorus changes into red phosphorus. Unlike white phosphorus, red phosphorus The poisonous effects of white phosphorus were has low solubility, is not spontaneously flammable, noted as soon as its manufacture for matches started and is not toxic. Red phosphorus can be made white growing. Already in 1869 Jacques Personne (1816- by heating at 533 K, amorphous black at 398 K, or 1880) carried experiments on dogs to show that crystalline black at 823 K. Like the white form, it will poisoning by phosphorus could be remedied with combine directly with oxygen, sulphur, halogens, and turpentine31. An interesting fact is that by that year metals, although the reactions are generally less police reports showed that the toxic action of vigorous27. phosphorus had put it in the first place of poisonous Red phosphorus can be prepared by prolonged substances used for criminal purposes. This heating the white variety at 525 to 605 K in a closed substitution had come as a result of the wide use of vessel for about 48 hours. The conversion is chemical matches and phosphorus paste for accelerated by a trace of iodine. It can also be destroying obnoxious animals. It was most dangerous obtained by exposure of phosphorus vapour to an because medicine had no antidote for combating its electric glow discharge, to a spark discharge, or to a action: victims would eventually die. Personne was heated tungsten filament. It does not ignite in air at led to study the possibility of using turpentine as an ordinary temperature and is not dissolved by the usual antidote from the medical case in which an attempted solvents for white phosphorus. Upon prolonged suicide used phosphorus as poison and also drank heating, the ordinary amorphous form of red turpentine oil in an attempt to accelerate his death and phosphorus undergows progressive exothermic, make it certain. Surprisingly, the suicide failed. irreversible transitions to crystalline modifications. Personne made 15 experiments using dogs. All the In 1914 Percy Williams Bridgman (Nobel Prize in animals were administered phosphorus, some of them Physics, 1946) studied the behaviour of phosphorus at received turpentine oil one or two hours after very high pressures and found that there are two ingestion of the poison, while others received varieties of red phosphorus, a bright brick-red one turpentine immediately after being fed phosphorus. formed by heating white phosphours to red heat at Most of the dogs which received turpentine 500 bar in a nitrogen atmosphere, and a violet immediately or one or two hours after phosphorus phosphorus made by heating white phosphorus under survived, although were very sick for some time. pressure in the presence of sodium as a catalyst. The Personne postulated that phosphorus killed by density of the violet variety formed was 2.348 g/cm3. hindering hemoglobin of blood and depriving it of The violet form is the stable one between 8,000 and oxygen, death being fast if absorption by blood was 12,000 bar at 473 K32-24. rapid and slow if it was slow. In the first case death was actually by asphyxia, in the second it resulted (c) Black phosphorus from hemoglobin failure. It seemed that the absorbed This is the thermodynamic most stable form of the turpentine hindered the action of phosphorus in blood element and exists in three crystalline and one in the same way that it hindered its combustion in air amorphous form, all of which are highly polymerized, 116 INDIAN J. CHEM. TECHNOL., JANUARY 2005

insoluble, and practically non-flammable. Black The first organic phosphorus compound to be phosphorus is obtained by subjecting white phosphorus identified was probably lecithin, isolated from brain to a pressure of 35,000 bars at ordinary temperature or fat in 1811 by Louis Nicolas Vauquelin (1763- to 12,000 bars at 473 K32-34. This allotropic form is a 1829)38, and characterized as a phosphorus-containing flaky crystalline material resembling graphite and has a lipid by Nicolas Théodore Gobley (1811-1876) in density of 2.699 g/cm3. It is a conductor of electricity 185039. In 1868 Friedrich Miescher (1844-1895) with a resistivity of 0.711 ohm per cubic centimeter isolated nuclein from pus cells obtained from surgical and is not dissolved by any of the liquids that dissolve bandages. This represented an important step in the white phosphorus. Under ordinary pressure black association of phosphorus compounds with living phosphorus changes irreversibly into the red allotrope tissues. at about 823 K. The earliest laboratory synthesis of an organic In the eigtheenth and nineteenth centuries, many phosphorus compound was reported by Jean-Louis salts of phosphoric acids were prepared in crystalline Lassaigne (1800-1859) in 1820, who obtained crude form. Heat resistance was considered one of the alkyl phosphates by reacting alcohols with phosphoric outstanding characteristics of phosphoric acid. Further acid. This was followed by the synthesis of phosphine experimentation on the drying and heating certain of derivatives by Louis-Jacques Thénard (1777-1857) in phosphates revealed that three kinds of phosphoric 1840 and by the end of the century quite a number of acids could be produced: ortho, pyro, and meta. In compounds containing both phosphorus and carbon 1830 Jöns Jacob Berzelius (1779-1848) introduced the had been produced. concept of allotropy, which was to collect all cases of It is now accepted that phosphorus compounds play equal crystal form in compounds in which equal a vital role in living processes and are essential for the numbers of atoms of different elements are put together growth, development, and maintenance of all plants in the same manner. Berzelius mentioned the different and animals. They are present in soil, bones, and phosphoric acids as examples of isomeric compounds. teeth, and in blood and all cellular organisms. Energy- A few years later Thomas Graham (1805-1869) transfer processes such as photosynthesis, proved that the three phosphoric acids were not metabolism, nerve function, and muscle action all isomeric and characterized them as a "terphosphate, a involve phosphorus compounds27. biphosphate, and a phosphate of water". Actually this was the wrong terminology for what he meant, he Development of the manufacturing process actually formulated a trihydrate, bihydrate, and 35 In the years after 1770, phosphorus was discovered monohydrate of phosphorus oxide . in bones and many other parts of various animals. Justus von Liebig (1803-1883) used the analogy he Treatment with sulphuric acid decomposed these observed with certain organic acids to formulate the materials into a solid residue and dissolved phosphoric acids as compounds having a constant phosphoric acid. This was the first method of proportion of water and varying proportions of 36 phosphorus commercial production. In the 1800s "phosphoric acid" . According to Liebig, salts were Bertrand Pelletier (1761-1797) further developed the formed when a basic (i.e., metal oxide) replaced water. process invented by Scheele for the production of The acids from the two lower oxides of phosphorus white phosphorus for matches40. Bone ash was first were also considered as three-basic. Adolphe Würtz reacted with sulphuric acid to produce Ca(H2PO4)2, (1817-1884) formulated them according to the theory 37 which was then reacted at high temperatures with of chemical types as : wood charcoal to form white phosphorus, Ca (PO ) , 3 4 2 and CO. Only two-thirds of the phosphorus in the ⎡⎤PO 3 26 ⎢⎥3 O Phosphoric acid Ca(H2PO4)2 was recovered as white phosphorus . ⎣⎦H In a long entry on phosphorus, published in Macquer's chemical dictionary41 Edmond Willm ⎡⎤PHO 2 ⎢⎥2 O Phosphorus acid wrote: “For a century, urine was the only source from ⎣⎦H which phosphorus was obtained. After Johann

Gottlieb Gahn (1745-1818) recognized the presence 2 ⎡⎤PH O of phosphoric acid in bones, Carl Wilhelm Scheele ⎢⎥O Hypophosphorus acid ⎣⎦H (1742-1786) indicated the procedure for making EDUCATOR 117

phosphorus from them”. A few years later, Scheele sixteen hours the phosphorus distilled over and corrected Gahn’s assumption that the sal cosmicum condensed at the bottom of the troughs. From this was an ammonia salt; instead it is a “tertiary neutral stage onward the phosphorus had to be kept under salt, consisting of alkali minerali fixo (i.e., sodium), water, since it is spontaneously combustible on alkali volatili, and acido phosphori"2,42. exposure to air. The crude phosphorus from the clay According to Wagner43, calcined bones contain 9.4 retorts was cooled, and left settling into 10-12 kg to 10 wt. % of calcium phosphate, 2.2 to 3.0 wt. % of blocks called cheeses, to be then refined distillation in tribasic magnesium phosphate, 83 to 84.4 wt. % of the presence of sodium dichromate and sulphuric tribasic calcium phosphate, and 3.9 to 4.1 wt. % of acid. The chromic acid generated oxidized the lower calcium fluoride. They are decomposed by sulphuric oxides of phosphorus, and pure phosphorus, almost acid according to: colourless, was produced. Another purification process was based on a simple distillation in iron

Ca34224 (PO )+→ H SO 2CaSO 4 + CaH 442 (PO ) … (3) retorts. The resulting phosphorus was then soldered 43 into tins for dispatch . The acid calcium phosphate, mixed with carbon in Serious commercial production of phosphorus appropriate vessels, decomposes to calcium compounds from apatite ores started in Europe about metaphosphate and water: 1850 when Arthur Albright (1857-1926) and John Edward Wilson (1855-1907) begun production of CaH (PO )→+ Ca(PO ) 2H O … (4) white phosphorus in England. Gas-fired furnaces were 442 322 introduced by Coignet et Cie. in La Guillotière, near

Lyons, France, but a more revolutionary development Further heating to white red decomposes the calcium occurred in 1888 with the introduction of the metaphosphate: electrothermal process, patented by James B.

Readman44 and T. Parker and A. E. Robinson45. The 3Ca(PO )+→ 10C Ca (PO ) + 10CO + 4P … (5) 32 3 42 development of the electric furnace enabled switching from the costly batch method of manufacture The above reaction releases about two thirds of the originally invented by Friedrich Wöhler (1800-1882) phosphorus present in the metaphosphate. in 182946, to an economical continuous industrial Until about 1890, the general method of process. In the electrothermal furnace process the phosphorus preparation was to treat ground bones, or furnace is charged with a mixture of lumps of mineral mineral phosphates such as apatites, with hot phosphate, coal, and sand, and heated to 1700-1800 sulphuric acid of specific gravity 1.55 in large circular K. The silica combines with the phosphate rock to wooden vats lined with lead, provided with slow give calcium silicate, a slag, and phosphorus agitation and heated directly with steam. The products pentoxide. The pentoxide is then reduced by the coke were soluble phosphoric acid, which remained in to give phosphorus vapour and carbon monoxide. solution, and insoluble calcium sulphate (gypsum), Slag is removed periodically and there is a continuous which settled out. The gypsum separated and was evolution of vapourized phosphorus. The phosphorus sold, when possible, to manure makers. The is condensed and cast into sticks, which are kept phosphoric acid concentrated by evaporation to about under water. The carbon monoxide can be used as a 62 wt. % phosphorus pentoxide. The syrupy solution fuel47. With fluroapatite the reaction proceeds of phosphoric acid was then mixed with about one- according to the equation: fourth of its weight of ground coal, charcoal, or other carbon, and dried in iron pots, at a temperature 4Ca (PO ) F++→ 18SiO 30C 3P 343 2 4 … (6) sufficient to convert he orthophosphoric acid to ++30CO 18CaSiO32 + 2CaF metaphosphoric. The resulting black mass was powdered and loaded into fireclay retorts, each about The overall yield of the process is about 91%, 1.2 m long and 0.2 m wide, into which short cast iron based on the phosphate rock used. The largest loss of stems were luted. The charged retorts were loaded yield is associated with the slag. The conversion of into a furnace fired by coal, in such a way that the white phosphorus into the more stable red form is an ends of the iron stems dipped beneath the surface of exothermic reaction that must be carried out under water in a long trough. During the course of some controlled conditions. 118 INDIAN J. CHEM. TECHNOL., JANUARY 2005

According to Ullman26, a single-phase furnace of Giant vertical carbon electrodes are employed and 80 kW was constructed in England in 1893, and soon reduction to elemental phosphorus takes place at phosphorus was being produced in tonnage quantities 1700-1800 K. In spite of the heat of combustion of the in electric furnaces in the U.S., France, and Germany. coke, the reaction is highly endothermic and requires In 1925 the first three-phase electric furnace (3 MW) an input of about 12,000 kW per ton of phosphorus was built in Bitterfield, Germany. In 1927, four 10 produced. The most effective phosphorus production MW were built in Piesteritz, and similar large technology uses a submerged arc furnace, which furnaces were built in the U.S, in the 1930s. After performs three functions: chemical reactor, heat Word War II, phosphorus production worldwide grew exchanger, and gas-solid filter, respectively, each of very rapidly. Many furnaces with power of up to 70 which requires a significant amount of preparation for MW per furnace were built in the U.S., Canada, the the solid furnace feed materials. Netherlands, Germany, the Soviet Union, and China. More silica (in the form of quartzite), in addition to In spite of many design and operation improvements the one present in the ore, is usually added to facilitate of electrical furnaces, Readman's method is still the the reaction. The silica serves two purposes. First it basis of present technology for producing to lowers the slag melting point, and second, it combines elementary phosphorus. with the lime present in the ore to improve the In the modern industrial method for the production thermodynamics of the reaction. Controlling the of phosphorus, phosphate rock, coke, and silica melting point of the slag is critical for optimizing pebble are charged continuously into a three-phase phosphorus production30. electric furnace. The electric energy is used only to There are several theories about the course of the heat the charge, which melts and reacts chemically the reaction, but the actual reaction mechanism in the coke and silica to produce phosphorus vapour and electric furnace is still unknown and may vary carbon monoxide, which pass out of the furnace, depending on the location in the furnace. According while a molten calcium silicate slaf accumulates in to a very detailed study of the reaction Kriklivy48 the furnace. Any iron compounds present as came to the conclusion that the most likely course of impurities are reduced and then molten metallic iron the reaction is through an acid displacement absorbs phosphorus to form ferrophosphorus, which is metathesis, in which the calcium phosphate is first heavier than the slag and falls to the floor of the redcued to metaphosphite and then to phosphorus, as furnace. Afterwards, the gas is freed from dust and per the following reactions: then cooled: the phosphorus condenses to the liquid 30 2Ca (PO )+ 6SiO→+ 6CaSiO P O … (10) and eventually to the solid form . 3422 3410

Elemental white phosphorus is produced from a PO+ 10C→+ P 10CO … (11) phosphorus-rich ore mostly mined by strip mining. 410 4 This ore usually contains fluorapatite, plus some silica Red phosphorus is manufactured from white and silicates. When a carbon source, usually coke, is phosphorus for applications such as striking surfaces added to the ore at temperatures greater than 1400 K, for matches, fireworks, flame retardants in polymers, the following general reactions occurs: semiconductors, and phosphine used to manufacture semiconductors. The batch conversion requires one to 2Ca F(PO )++→ 9SiO 15C two days and involvers heating molten white 5432 … (7) 9CaSiO32++ CaF 15CO + 3P 2 phosphorus at temperatures somewhat below its 30 boiling point of 553.3 K . 2Ca (PO )++→ 6SiO 10C 3422 … (8) Patterns of use and historical development of the market P++ 6CaSiO 10CO 44 Elementary phosphorus is used in pyrotechnic applications, such as fireworks, luminous projectiles depending on the type of apatite used. and matches, in the metallurgical industry to form At the lowest reaction temperature P4 tetrahedra metallic alloys as the phosphorous brass, in the rather that P2 dimers may be produced, or as the gas production of insecticides, as additive of industrial cools, dimers combine as: oils, and in the electronics industry (in the form of phosphides). As phosphoric acid it is used as additive

2P24→ P … (9) for certain drinks as well as in the cleaning of some EDUCATOR 119

metals or as phosphatizing agent. The largest fertilizers had become the most important commercial application is in the form of different salts. The uses for phosphorus compounds. fertilizer industry is the largest consumer of phosphate The use of bone as fertilizer dates from Biblical rock. There are several types of fertilizers obtained times since in those days it was known that the best from phosphates, usually mixed with potash or place to plant a vineyard was where there had been a ammonia salts. The phosphate salts are also used in great battle. The ancient way to overcome phosphorus the production of synthetic detergents (sodium deficiency was to spread crushed animal bones over polyphosphate) and in teeth paste (calcium the land. The importance of phosphates in the phosphate). Some condensed phosphates are used in economy of vegetation was pointed out during the industrial water treatment. 1780s: guano was examined in 1805 and bones to the In the eighteenth century, phosphorus was a costly value of several tons were imported by Britain during material, produced mostly for display and to satisfy the first decades of the nineteenth century. Jean- curiosity. Guillaume François Rouelle (1703-1770) Baptiste Boussingault (1802-1887) traveled to Perú to demonstrated the process of extracting it from urine in see the guano deposits. Garcilaso de la Vega (1539- 49 the sixty-four laboratory session of his lectures . His 1616) noted in his history of Perú52 that the Incas used procedure was based on reducing with charcoal and guano a fertilizer. Two hundred years later Alexander lead chloride the sodium metaphosphate resulting von Humboldt (1769-1859) revived this knowledge from the thermal decomposition of the sodium- and Humphry Davy (1778-1819) wrote about the ammonia phosphate present in urine. Macquer, who benefits of guano to the soil. In 1833 the Duke of attended Rouelle's course, reports that he “very often” Richmond proved that the fertilizing value of bones 22 succeeded in making it . Boyle had the idea of using resided not in the gelatin, nor in the calcium, but in phosphorus as a light for underwater divers. A century the phosphoric acid. Thus he confirmed what Nicolas later, instant lights were sold with molten phosphorus Théodore de Saussure (1767-1845) had said in 1804 as the igniter, but they proved cumbersome and “we have no reason to believe” that plants can exist unreliable. Because white phosphorus is highly without phosphorus53. One hundred years after the poisonous, an active development of the use in discovery of cold light, the presence of phosphorus in matches had to wait until the conversion of the white plants and animals was ascertained, and its form was form into the red one had been studied by Émile Kopp established as a compound of phosphoric acid. This 50 (1817-1875) , Johann Wilhelm Hittorf (1824- knowledge had little practical effect until the nature of 51 1914) , and in its practical application, by Schröetter, the acid in its various forms, was explained through as explained before. the work of Graham2. By the middle of the nineteenth From the early beginning, the most exciting early century, the source of phosphorus in natural use, however, was in medicine. It is not surprising phosphates and the chemistry of its oxidation products that such a use was sought at that time. We have had been established. The main difficulty that had to already mentioned that Kunckel, shortly after he be overcome was that these oxidation products existed found how to prepare phosphorus, introduced it as a in so many forms, not only several stages of oxidation medicine capable alleviating a wide variey of but, in addition, aggregations and condensation of the ailments, from apoplexy to antidote against many phosphoric acids. Once the fundamental chemistry of poisons. His initiative was promptly followed by these acids was elucidated, the attention of chemists others. Phosphorus was prescribed in liniments with and physiologists turned to the task of finding the fatty oils or as solution in alcohol and ether, for actual state in which phosphorus compounds were external and internal application; it was recommended present in the organisms. Unknowingly at first, the for the treatment of epilepsy and melancholia, against farmer had supplied this element by means of the cramps, etc. organic fertilizers he used: manure, excrements, Louis Charles Derosne (1780-1846) invented the bones, and horns. Now, with the value of phosphorus first phosphorus-containing striking matches in 1812 known, a search began for mineral phosphates to be 2 and in 1842 John Bennett Lawes, (1814-1900) and applied as fertilizers . James Murray (1788-1871) took patents for the In 1808 some field trials of vitriolized bones were manufacture of phosphorus from sulphuric acid and made near Belfast, and it is recorded that this bones. By the end of the century matches and treatment yielded luxuriant crop. At first, to promote 120 INDIAN J. CHEM. TECHNOL., JANUARY 2005

the absorption of bones by vegetation they were By the 1870s Lawes was manufacturing some crushed or ground into a coarse meal, but by about 40,000 tons annually47. 1840 Liebig suggested that they might be rendered In the United States active developments of more soluble by treatment with sulphuric acid36. phosphate mining and treating started in South Liebig’s idea was not entirely new, since 1832 a Carolina in 1867 and in Florida in 1888. production of a superphosphate from bones and World production of white phosphorus increased sulphuric acid had been in progress in Prague. Imports from a few thousand tons at the end of the 1900s to into England rose and far exceeded those into France. 105 tons by 1939. By 1974, the year of maximum Between 1857 and 1867, about 50,000 tons were world production, this had increased to near 8.2×105 annually received2. tons. The reason for this large increase was the Superphosphate came into general use in the latter demand for tetrasodium phosphate and especially half of the nineteenth century. The first to try to make it pentasodium phosphate, used principally in the commercially was Murray. In 1835 he pointed out that manufacture of detergents. Increased use of phosphate superphosphate could be prepared by treating with detergents led to the suspicion that their residues were sulphuric acid not only bones but mineral phosphate leading to eutrophication of inland water. Beginning rock. Murray’s method of manufacturing superphos- in 1969, a movement to restrict and then legally ban phate, patented in 1842, consisted in mixing mineral the use of phosphates in detergents led to the closing phosphate with an equal weight of sulphuric acid in an of significant amounts of plant capacity. earthenware vessel, and well agitating the mixture for In 2002, world production of white phosphorus was two or three days. At the end of this time, it was mixed 650,000 tons, of which about 83% was used in the with some absorbent material, such as bran or sawdust, production of phosphoric acid, and of this about 50% yielding a dry, powdery fertilizer, easy to use. Murray's was used to manufacture phosphates for detergents. factory was closed after commercial failure. The remaining 50% of the phosphoric acid was used to make phosphates for foodstuffs, pharmaceuticals, The following attempt to manufacture and test and animal feeds. The remaining 17% of the superphosphate using Liebig’s proposal was that of phosphorus produced was used in the manufacture of Lawes in 1840 and 1841, with very satisfactory field phosphorus halides, red phosphorus, P2O5, and and commercial results. As a result, in 1842 he took metallic phosphides26. out a patent for the manufacture of superphosphate. In 1843 he started to make it in a factory at Deptford, The classical uses for red phosphorus are in the whence the manufacture spread throughout the world. striking surface of match boxes and pyrotechnics. A Lawes experimented with bones at his farm, treated continuously increased application is in the them with acid and discovered that his crop of turnips manufacture of various flame proofing preparations. more than doubled that produced by using untreated A considerable proportion is converted to metal bones. The following is part of Lawes' patent: phosphides, used in pest control agents. High-purity “Whereas bones, bone ash, and bone dust and other red phosphorus produced by distillation of PCl3, phosphoritic substances have been heretofore reduction to white phosphorus, and conversion to the employed as manures, but always, to the best of my red form, is important in the manufacture of semiconductors, especially gallium phosphide (for knowledge, in a chemically undecomposed state, 26 whereby their action on the soils to which they have laser diodes) . been applied has been tardy and imperfect… And it is World production of red phosphorus in 2002 was in particular well-known that the application of bone about 6500 tons. dust is of no utility… on account of the slow A considerable demand for phosphorus arose in the decomposition of the bone dust in the soil… Now, the first half of the nineteenth century for the making of first of my said improvements consists in matches. Preparation of phosphorus from bones in decomposing the said bones, bone ash, bone dust, and 1775 led to the invention of a phosphoric taper about other phosphoritic substances… I mix with the bones, 1781 and a briquet phosphoric by 1786. While neither bone ash, or bone dust, or with apatite or phosphorite safe nor satisfactory these instantaneous light a quantity of sulphuric acid, just sufficient to set free nevertheless remained in use for upwards of forty as much phosphoric acid as will hold in solution the years, being joined by Jean Chancel’s (he was an undecomposed phosphate of lime. :” assistant of Thenard) chemical matches (based on a EDUCATOR 121

mixture of potassium chlorate and sugar ignited by Table 2⎯Phosphate rock world production (103 metric tons)25 sulphuric acid) in 1805. The first friction match was invented by John Walker, who discovered that a 1998 1999 2000 2001 2002 mixture of antimony sulphide, potassium chlorate, Algeria 1,155 1,096 877 896 741 gum, and starch could be ignited by striking it against Brazil 4,421 4,344 4,725 4,805 4,850 any rough surface. Various forms of these matches China 25,000 20,000 19,400 21,000 23,000 appeared in the market under names such as Egypt 1,076 1,018 1,096 972 1,500 prometheans, lucifers, and congreves. These matches India 1,730 1,262 1,136 1,200 1,250 Iraq 1,000 1,000 650 300 300 had a number of problems: the flame was unsteady, Israel 4,067 4,128 4,110 3,511 3,500 the initial reaction was usually violent, and the odour Jordan 5,925 6,014 5,526 5,843 7,179 produced by the burning match unpleasant. Morocco 23,587 22,163 21,463 21,983 23,000 Phosphorus-containing matches are said to have been Russia 10,100 11,400 11,100 10,500 10,700 invented by Charles Sauria (1812-1895) who Senegal 1,478 1,814 1,739 1,708 1,500 South Africa 2,739 2,957 2,796 2,420 2,913 discovered that the unpleasant smell could be Syria 2,496 2,084 2,166 2,043 2,400 eliminated by additing phosphorus to the igniting Togo 2,230 1,600 1,400 1,060 1,281 mixture. For a time yellow phosphorus was used, but Tunisia 7,901 8,006 8,339 8,114 7,750 after Schrötter’s discovery of red phosphorus in 1847 United States 44,200 40,600 38,600 31,900 36,100 Others 4,895 4,514 6,867 7,745 5,536 Rudolph Böttger (1806-1881) reintroduced phosphorus-free match heads. The manufacture of Total 144,000 134,000 132,000 126,000 135,000 phosphorus for making matches was primarily 47,54 established in France and Germany . Morocco, each at 17% of the total (Table 2). The Although white phosphorus was prohibited in U.S. also accounted for nearly 8% of world reserves. matches in early 1900s because of its toxicity, U.S. phosphate rock production increased from 18 consumption continued to increase. The amount of million metric tons in 1960 to 35 million metric ton in phosphate rock used in electrothermal production of 1970 and peaked at 54 million metric ton in 1980. elemental phosphorus has decreased. In 1959, ca. Consumption in 2002 was 36.1 million metric tons. 11% was used, in 1977 ca 6%, and in 2002 ca. 4%. Increasing tonnage of phosphate rock is used to The reason is the increasing use for fertilizers. produce phosphatic fertilizers for the export market. Nowadays, the biggest part of white phosphorus The supply of phosphate rock is forecast to decline in production is converted to phosphate compounds. the U.S., as existing mines in Florida are mined out Sodium phosphate accounts for 47% and calcium, and unfavourable economics discourage new mine development. It is believed that world supply will be potassium and ammonium phosphates account for 25 17%. Final applications include home laundry and maintained from quality deposits in North Africa . automatic dishwater detergents, industrial and The U.S. share of total world production has institutional cleaners, food and beverages, metal decreased steadily. In 1959 it was 44%, in 41% in cleaning and treatment, potable water and wastewater 1977, and 27% in 2002. In 2002 more than 90% of treatment, antifreeze, and electronics. The remaining phosphate rock consumed in the U.S. was used to 15% of the elemental white phosphorus is used in manufacture wet process phosphoric acid make phosphorus-dependent applications, which require the chemical fertilizers and animal feed; the remainder element as a direct participant. The principal products going to production of elemental phosphorus and industrial phosphates55. include P2S5, PCl3 and POCl3, P2O5, and hypophosphite. Final applications include flame Epilogue retardants, lubricant additives, insecticides, As quoted by Threlfall56, Charles Reade (1814- herbicides, water treatment, cleaning compounds, 1884) allows himself a novelist's licence in his book plasticizers, and semiconductors30. The Cloister and the Hearth57 to discover a use of World production of phosphate rock was 135 phosphorus in the second half of the fifteenth century: million tons in 2002, with the U.S., China, Jordan, "While thus employed, Gerard was busy about the and Morocco having the largest tonnage increases. In seated corpse, and, to his amazement, Denys saw a that year the U.S. was the top producer, accounting luminous glow spreading rapidly over the white face. for 27% of world production, followed by China and Gerard blew out the candle. And the corpse's face 122 INDIAN J. CHEM. TECHNOL., JANUARY 2005

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