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Sodium Carbonate--From Natural Resources to Leblanc and Back

Sodium Carbonate--From Natural Resources to Leblanc and Back

Educator Indian Journal of Chemical Technology Vol. 10. January 2003. pp. 99-112

Sodium carbonate--From natural resources to Leblanc and back

Jaime Wisniak Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel 84105

The development of carbonate as a major commodity is intimately attached to the chemical revolution that took place in the eighteenth and nineteenth century. Strong politiclil and economical reasons led to the search of synthetic procedures to replace the natural sources of soda that were available by the seventeenth century. Eventually developed a synthetic process that used qommoQ salt as raw material. lmplfmentation of Leblanc's procedure led to such serious environmental problems, e.g., rain, that the first laws for environmental protection were enacted in England. Treatment of the obnoxious gaseous, liquid, and solid wastes of the process resulted in new processes for the manufacture of and sulphur. Leblanc's process came to an end with the development of the . Eventually, the discovery of huge fields of natural in the U.S. led to the decline of the Solvay process.

Up to the middle of the eighteenth century loom and manufactured from cotton, hemp, and linen carbonate (vegetable soda) and sodium carbonate fibres, had a grey colour and were bleached by (mineral carbonate) were obtained from natural primitive methods. The first stage involved repeated deposits or from the ashes of certain and washes with stale urine, , sour buttermilk, or seaweed. Ashes were produced from (potash or sulphuric acid, and the cloth was then laid out on th e pearl ash) imported from Eastern and the sunlight for three to sixth months. The process was Colonies; from seaweeds () growing in Scotland, very lengthy, depended on the weather and utilized Ireland, Norway, and Northern , and from vast areas of land that could not be cultivated. By the soda (barilla) , a salty growing in the end of the eighteenth century notable improvements Mediterranean coast of Spain. The two carbonates of the bleaching process came into being with the were an essential raw material for three growing discovery of the bleaching properties of chlorine by industries: it was used in the textile processing as an Claude-Louis Berthollet (1748-1822), and the alkaline scour in the bleaching of linen and cotton manufacture of bleaching powder. Later on, it was cloth; in glassmaking as a fluxing ingredient to lower discovered that sulphuric acid could be used to the melting point of soda lime glass compositions; mordant indigo on wool. Indigo, one of the most and in -making. Development of synthetic popular dyes of all times had previously been methods for manufacturing sodium carbonate may be colourfast only on cotton and linen (Note I). considered as the catalyst led to the chemical Nevertheless, the limited amounts of sulphuric acid revolution. Synthetic methods provided the answer to and chlorine available and their relatively high values the economic bottleneck created by limited supplies did not allow use of these techniques for the mass of the traditional raw materials. In the beginning, production of white clothes. increased imports provided partial release to the Leblanc's development of the synthesis of sodium scarcity problem, but the political situation and carbonate from common salt led eventually to a expanding economy of Europe made this alternative substantial decrease in the price of soda and chlorine. short-lived. the latter obtained from the by-product hydrogen A good example of the problems involved is that of chloride. Not only that, the synthesis released the the bleaching processes employed by the textile industrialized countries from the need to import the industry before the synthesis of sodium carbonate was chemical and be a servant of other countries. achieved. The different fabrics coming out from the Development of sodium carbonate as a major chemical commodity is interesting because of the *For correspondence: wi sniak @bgumail.bgu.ac.il stages it went through; first, exploitation of natural Educator Indian J. Chern . Techno!., January 20m

resources, followed by chemical synthesis, and a between Alexandria and Rosetta, he "saw here and return to the use of natural resources in the twentieth there a few unhusbanded Palmes, Capers, and a weed century. called Kall by the Arabs. This they use for fuel and We will now describe these three stages and the then collect the ashes which crusht together th ey sell social, political, economical, and industrial events that in great quantities to the Venetians; who equall y accompanied it. mixing the same with stones make thereof their crystalline glasses". Natural resources When the Arabs settled in Spain about the seventh Natural deposits of sodium carbonate have been century, they substituted the soda resources available known and used from ancient times. In Book XXXVI in northern Africa by the cultivation of a sea shore of hi s "Natural History", Pliny writes about the plant, to which they gave the name kali or , discovery of glass by a "mercaturum nitri" (merchants probably derived from the Hebrew root meaning to 2 of nitre): "There is a story that once a ship belonging burn . After expulsion of the Arabs, th e Spaniards to some traders in natural soda put in here and that changed the name of the plant to bariglia in the XV II they scattered along the shore to prepare a meal. century and to barilla in the XVIII century. 2 Since, however, no stones suitable for supporting their According to Patterson , it is reasonable to assume cauldrons were forthcoming, they rested them on that the Arabs also manufactured alkali by charring lumps of soda from their cargo. When these became the argol or tartar (potassium hydrogen tartrate) that heated and were completely mingled with the sand on precipitated in wine casks. the beach, a strange translucent liquid flowed forth in In the old days, the words natrum, kali, and soda streams; and this it is said, was the origin of glass'". were used without distinction. In the thirteenth According to Patterson2 in the north of Africa, century the name sal nitri came to be used for south of Tripoli , there are vast deposits of a double potassium nitrate, in place of sal petrosum, and thi s sal t of sodium carbonate and , was shortened into nitrum and ultimately became Na1COJ.2 NaHC03.2H20 , not being commercialised nitre, in English; but the words kal i and today. The Egyptians probably knew of them, and continued to be used indiscriminately for potassium 2 also the Israelites, who called it nether. According to carbonate or sodjum carbonate . the Encyclopaedia Biblica3 the material was called Sodium carbonate and became neteru by th e Accadians, nitri by the Egyptians, and differentiated clearly only in th e seventeenth century vtrpov (nitron) by the Greeks. Later on, the Arabs after Henri Louis Duhamel du Manceau ( 1700- 178 1) call ed it natron, which became shortened to tron and and Andreas Sigmund Marggraff ( 1709- 1782) trona. All th e different names were simply vanations determined their properties. of the Egypti an name meaning clean, real. Old We will now discuss the different natural sources 1 Egypti an documents from the 18 h dynasty indicate in more detail. th at nitri was present in natural fields located in Wadi Natural deposits- Soda forms part of the elements Natrun, next to Naukratis in the Delta, and near EI­ of a large number of mineral sources. It is present in Kab, in Upper Egypt. The ancient Egyptians exported the mineral of Karl sbad, Burtscheid, and the salt to many countries and the beli evers used it to Vichy; in the of geysers in Iceland ; as clean their mouth by chewing it wet, as a component efflorescence in volcanic rocks, trasoite and egneys of the incense , and also as a component of (such as Bilin in Bohemi a). In Hungary sodium mummifying materials. carbonate effloresces during the hot season in the 5 The word nether is mentioned twice in the Bible, in form of a crystalline crust, called Szekso • both cases in relation to its cleansing properties Efflorescences or crusts originate during periods of (Note 2). hot weather from the partial or total evaporation of The ancients also knew that the ashes obtained by lakes without outlets, or from evaporation of the soil bu rn ing seaweed and land plants had properties very humidity that ascends to the surface by capill ary similar to those of the natural material. Plant ashes forces. The sodium carbonate present in salt lakes were at one time produced in Egypt and other probably originates from the reaction between sodium 4 countries. As quoted by Lucas and Harris , the chloride and . It is likely that the explorer G. Sandys wrote in 1610 that when travelling initial stage is the reduction of sodium sulphate to

100 Wi sniak: Sodium carbonate Educator sodium sulphide, under the influence of organic developed a system for accumulating water to avoid substances. The sulphide is then transformed into the decrease in osmotic potential caused by the carbonate under the action of dioxide increased salt concentration. dissolved in water. When these waters accumulate in Plants resistant to high salinity belong mainly to lakes without outlets and having a large rate of the genus Salsola, Salicornia, Atriplex, Statice. evaporation, they may produce a crust containing Chenopodium, and Fucus. The predominant species in sodium carbonate, particularly as sesquicarbonate, Spain is , and are usually called barillas. Na2C03.2NaHC03.2H20. In France the corresponding variety belong to the The oldest and best-known natural fields of sodium genus Salicomia and the product is called soda of carbonate are those located in the basin of Wadi salicor or Blanquette. Natrun, in Lower Egypt. The water of the eleven lakes Wagner5 has classified the ashes of the plants and located in the area is strongly alkaline, containing seaweeds used to manufacture sodium carbonate, , sulphate, and carbonate with a total according to the countries and methods of concentration of about 30%. The water level of the preparation, as follows: lakes reaches a maximum in the month of April and in (a) Barilla: soda from Alicante, Cartagena, Malaga, extremely hot summer several parts of the lake dry and Canaries Islands. It was extracted from barilla totally producing a saline crust 40 to 50 em deep, (Salsola soda), which was cultivated in the shores of containing about four percent sodium carbonate and Spain. The ashes contained twenty-five to thirty twenty-five percent sodium bicarbonate. In ancient percent sodium carbonate. times this crust was broken and carried in baskets on (b) Salicornia or soda of Narbonne, obtained by the boats sailing the Nile towards Alexandria. From there of Salicornia annua, which was planted it was exported mostly to the glass factories located in by seeding and collected after the grains had matured. Venice, to the tune of 2,500 ton/year. The soda The ashes contain about fourteen percent of sodium originating from Egypt was called Tro Na (from carbonate. where comes the word natron\ (c) Blanqueta, or soda from Aigues Mortes. It was Sodium carbonate was also known to exist in prepared from the seaweeds that grow between Aguas Mexico, where it was called tequixquitl, tequisquilit 6 Muertas and Frontignan: Salicornia europea, Sa/sola or tequesquite. According to Femandez in pre­ tragus, Salsola kali, Statice limonium, and Atriplex Colombian times it was used for food seasoning; after portuladoides. The ashes contain between three to the Spanish conquest it began to be used in the eight percent of carbonate. manufacture of glass and soap. In Colombia, there is a (d) Soda of Araxe: was used extensively in salty lake in Lagunillas, near Merida where soda southern and had the same commercial value (called urao) crystallizes in its bottom at a depth of as blanqueta. It was manufactured in Armenia, three meters from there divers collected it. Gathering Scarus, and Araxe. lasted about two months and yielded about eighty tons (e) Varek soda: it was prepared in Normandy and of sodium carbonate. Jean-Baptiste Boussingault Brittany from different seaweed species, particularly ( 1802-1887) described the operation at Lagunillas. from Fucus vesiculus (goemon). It was less valuable During the Spanish conquest, urao was used to than the previous item. prepare a thick tobacco juice. (f) Kelp: had the same value as varek and was Seaweed and plants--Plants growing in land manufactured in the west coast of England (Scotland, absorb potassium from the ground and their ashes Ireland, and the Orkneys) from different species of contain the element in the form of potassium Salsolaceas and algae (Fucus serraturs, Fucus carbonate. Plants growing near or in the sea contain nodosus, and Laminaria digitata), and in Jersey large amounts of magnesium and sodium soluble Island from Zostera marina. salts; the latter appears in their ashes as sodium The seaweeds and plants were processed as carbonate. High soil salinity is deleterious to normal follows: plants; the ones that survive have done it by developing several physiological features. For (a) Seaweeds 7 example, their leaves have foliar glands that excrete The name varech is generally given to all the plants the salts in an active manner; they have also that live in the sea at a low depth and are left on the

101 Educator Indian J. Chern. Techno!., January 2003

shore by the low tide. The word has many that dissolved the soluble components. The lixiviates explanations, for example, a derivation from an old were concentrated and evaporated; sodium chloride Norman word that originated from the English wrack precipitated first, followed by potassium chloride and or wreck (sea wreck). For others, it originated from a sulphate. At this point the mother liquor had a density Scandinavian expression meaning literally thrown by of about 55°Be and contained the iodides of sodium the sea. The difference between both explanations is and potassium, the sodium chloride that had not marked, but the sense remains the same. The crystallized, sodium sulphate and carbonate, , orthography of the word has changed. When Bernard polysulphides, as well as the sulphites and Courtois (1777-1838) started using seaweed for hyposulfites that originated during the increased manufacturing iodine it was written either vareck or reduction of the sulphates during the calcination varec. The term varec was also used to design the process. soda that was prepared from it. Today, the word is The reader interested in a detailed description of used to describe certain phanerogams, among them the varech industry is directed to the works of Clow8 9 Zostera marina L. , used for the manufacture of and Clow and Clow . vegetable fibers for packaging and upholstering. For a better understanding of the utilization of The plants used for producing varech were brown materials like kelp it is necessary to consider that algae, particularly of the focus variety; the goemons several European countries had established a salt (seaweed) included various species of Fucus and duty, which varied depending on the region and the Laminaria, depending on the sea depth from which source of the salt (marine or mined). The waste they were collected. The soda processors gathered products of the soap, glass, and bleaching industries particularly the black goemon formed by the Fucus were particularly valued as they contained hi gh and the Ascophyllum (Fucus nodosus) varieties. All percentages of salt, which went generally untaxed. the algae species contained, after calcination and Kelp is a mixture of sodium carbonate, sodium treatment, the carbonates, chlorides, sulphates, chloride, sodium sulphate, magnesium sulphate, bromides and iodides of sodium, potassium, magnesium chloride, and other minor constituents. In magnesium, and calcium. those days, some of these components were as In France and in England collection of the various valuable as sodium carbonate, hence more intrinsic goemons was subject to very severe administrative value per unit weight. For example, some samples of regulations because of accusations that it affected the kelp contained up to 25% of sodium chloride, an income of fishermen as well as created serious essential ingredient for manufacturing soap that could pollution problems. be had without pay~ng the salt excise. Similarly, The production procedure was very simple. The glassmakers were not taxed by the presence of salt algae that were carried inland at the time of low tide unless a very high percentage was present. Even the were dried on the beach, incinerated at the collection insoluble residue of kelp was valued as manure. pl ace and the ashes sent to the factory to be lixiviated. Soap makers used kelp to manufacture caustic The incineration was done in a longitudinal pit soda. First it was ground to a fine powder, and then excavated on the ground of the shore; the bottom of dissolved in water, the solution treated with calcium the pit was covered with flat stones and to this were , after which it was well stirred and filtered: added the algae that had been dried before. Fire was . . . ( I ) started with furze, little by little, to assure the combustion of the whole batch. The temperature had The soap maker was clearly interested in kelp to be high enough to insure the fusion of the ashes. having the highest alkali content si nce it was usually The fused mass present at the end of the process was sold independent of its composition. More alkali broken by throwing water into it. The kelp thus meant less expense in labor and equipment. produced was a vitreous grey conglomerate, similar to Processing of kelp is mentioned in Scottish iron slag, caJled raw soda or soda ash. Sodas of good writings as early as 1694, but it was not until about quality contained between three and thirty percent 1730 that production records started to be kept. 10 weight of carbonates and 0.8 to I percent of iodine. According to Stanford , at the height of the industry Lixiviation was done at the production site. The the maximum British production was about 28.000 blocks of ashes were subjected to the action of water tons per year. At that time twenty-four tons of algae

102 Wisniak: Sodium carbonate Educator were required to produce one ton of kelp containing to powder. For this reason they were thrown into a 6 25 to 50 kilograms of sodium carbonate. In spite of new pit and re-processed with the next batch . this small yield, the extraction of kelp occupied in the There are few data regarding Spanish barilla Orkneys about 20,000 persons. production and its export although at its peak it was Kelp production declined substantially after custom probably near 4,000 ton/year. taxes were eliminated on barilla imports, subsequently The soda ash obtained from plants and seaweed it became important again after Bernard Courtois was a low-percentage material; e.g., Spanish barilla (1777 -1838) discovered iodine in it. The immense contained 25 to 30% Na2C03, varec from Normandy value of iodine in medicine and photography gave a 3 to 8%, and Scottish kelp 10 to 15%. The soda ash second impulse to the manufacture of kelp. produced from plants was very expensive, and the processes used were labour intensive and too (b) Barilla primitive for mass production and consumed vast In the eighteenth century the high sodium quantities of vegetation. carbonate of Spanish barilla (Salsola soda L., Chenopodiadeae) made it the preferred raw material; Early synthetic processes unfortunately the many wars between Spain and As mentioned before, by the end of the eighteenth Britain made its supply uncertain, with the result that century the difference between the two fixed , Britain and France took steps to augment domestic sodium and potassium carbonates, was already supplies of soda from other sources. known. The sodium salt, barilla, wa<; largely made Salsola soda is an erect glabruous annual, 50 to 80 from ashes of seashore plants and seaweeds while the em high, with succulent leaves. It is a very tough potassium carbonate salt, potash, was made from the plant, resistant to environmental stress, needing only ashes of land plants. Of the two alkalis, potash was periodic watering and weeding. It is spread in South the most important because it was cheaper and more Europe, particularly in marginal areas near the coast. readily available than barilla. European countries. Barilla plants were also cultivated to reclaim brackish particularly France and England, satisfied their swamps. For many years it was an important cultivar demands by importing barilla from Spain and ash since it was possible to develop it in those salty lands made from pine trees grown in the cool, temperate where no other crops would give a good yield or in regions of continental Europe. those areas where irrigation was possible only with It was a time of vigorous industrial development salty water. The yield of barilla was about 0.6 ton per Many chemical industries, such as the mining, hectare. metallurgical, metalworking, glass manufacturing, In the middle of the XVlll century barilla was soap boiling, textile trades, etc., were demanding cultivated in Spain in Granada, Seville, Aragon, and a increasing amounts of wood and vegetable soda. large part of La Mancha. The seeds were collected in Since vegetable soda was also produced from wood September and planted between October and January. ashes, a timber shortage started developing, helped by The plants were dried in the sun and then burnt by a the many wars that were taking place at the time and procedure similar to that used for seaweeds. Round by producing countries protecting their resources pits of one to two meters diameter and 0.7 to 0.9 m (Note 3). In addition, barilla supply was erratic, not deep were made in the ground of the fields were the only because it came only from Spain but also plants were grown. The capacity of these pits varied because of war blockades. The net result was demand between one to three tons of dry plants. During the growing more rapidly than supply. burning stage the contents were mixed every so often By 1750, the demand for soda ash and potash to assure a homogeneous operation. The resulting exceeded the industrial capacity for producing it from product was a solid block of ash, of a blue gray color, the traditional sources. The inelasticity of this natural that in addition to sodium carbonate contained sodium supply, combined with obvious mercantil ist nitrate, sand, and the ashes of foreign plants. The considerations, created the incentive to meet the block was usually broken into pieces weighing growing demand with a practical method for between 200 to 300 kg each. The smaller pieces were converting salt from seawater directly in to not commercialized because in contact with the commercial soda. It was well-understood that if a atmosphere they started efflorescing and then reduced means could be found of preparing sodium carbonate

!OJ Educator Indian J. Chern. Technol., January 2003 readily from sodium chloride, alkali supply problems 1783 Louis-Bernard Guyton de Morveau (1737 -1816) 11 14 would be solved . • implemented a modified version of this process that The French government recognized this difficulty remained in operation until 1794. In Guyton de in 1775 when the King Louis XVI offered a 2,400 Morveau's procedure marine salt was with moistened livres prize through the Academie des Sciences for a slaked (jme and the mixture allowed to stand for some practical process for making of artificial soda from time, after which the alkaline efflorescence was common salt. The offer stimulated research not only laboriously scrapped by hand. in France, but also in England and other countries. Another important contribution to the problem was The prize was proposed during several years but no that of Duhamel who converted common salt into entry was judged good enough. Glauber's salt by heating it with sulphuric acid and Many processes were proposed before and after the then converted the sodium sulphate into sulphide Academie decided on a prize award. (hepar sulphuris) by heating it with . In 1658, Johann Rudolf Glauber (1604-1668}, in According to Duhamel he had thus "rompu en partie hi s book De Natura salinum, described the Sal !'union de l'acide vitriolique avec Ia du set Mirabili Glauberi (Na2S04.10H20}, the residual marin, parce que dans cet etat Ia force del' acide product in the preparation of , a salt vitriolique se trouva partagee entre Ia matiere that was regarded as miraculous, partly because it had inflammable et le Sel alkali" (I have broken apart the medicinal properties, and partly because it was union between vitriolic acid and the base marine salt supposed to dissolve carbon, since strongly heated because in this state the force of the acid is di stributed 18 1 with carbon, the product, carbon disulphide, was between the flammable part and the alkaline salt) · 'J. sol ubl e in water. Afterwards, Duhamel treated the sodium sulphide According to Henrik Theophilus Scheffer15 (1710- with vinegar to convert it into sodium acetate and 1759}, about 1770 Carl Wilhelm Scheele (1742-1786) evaporated the solution to dryness, without isolating had proposed preparing by reacting the salt. Strong heating of the solid yielded a fetid oi I sodium chloride with lead oxide. Powdered litharge distillate. According to Duhamel the residue left was (PbO) was percolated in a funnel with a marine salt "sel alkali fixe car en effet que pourroit il m'etre reste solution to produce a solution of caustic soda autre chose" (fixed alkali salt because it could not be something else). 2NaCL + PbO + H 0 ~ 2NaOH + PbC/ (2) 2 2 Duhamel's procedure involved the following 2NaCl + PbO + H 2 0 ~ 2NaOH + PbC/2 (3) reactions: The caustic soda thus produced could be 2NaCL + H S0 ~ Na S0 + 2HCL (5) carbonated by exposure to air. In 1782 Richard 2 4 2 4 2C ~ 2C0 (6) Kirwan (1733-1812) in England made an Na2 S04 + Na 2 S + 2 unsuccessful attempt to work this process on a Na 2 S + 2CH 3 COOH ~ 2CH 3 COONa + H 2 S (7) manufacturing scale. CH 3COONa ~ Na2 C03 + (CH 3 h CO (8) As will be described below, Pere Malherbe modified Scheele's method by substituting sodium Guyton de Morveau wrote that Marggraf and sulphate for , iron filings for litharge, and by Duhamel had in a way exhausted the resources of adding or charcoal to the mixture. without reaching success in attempts to find 16 Torbern Olof Bergman ( 1735-1784) wrote that an economical w;Iy for making soda from common 20 Scheele obtained soda from common salt by the salt . action of iron in the presence of air and water; Baud2 1 has built an interesting timetable describing afterwards sodium carbonate was formed as the events that took place from the moment the efflorescence. Academie requested proposal s for converting common salt into sodium carbonate and Leblanc' s 2NaCl + 4Fe + 6H 0 + 30 ~ 12NaOH + 4FeCl2 2 2 procedure: ... (4) (a) 1776: Establishment of a prize by the Academi c In 1779 Scheele proposed an alternative route for to reward the author of an industrial process "en vue manufacturing sodium hydroxide, based on reacting d'extraire I' alkali pur du sel marin, sans que Ia valeur 17 sodium chloride with lime in the presence of iron • In de cet alkali mineral excedat le prix de celui qu'on

104 Wisniak: Sodium carbonate Educator tire des meilleures soudes etrangeres". (to extract the following months Leblanc performed additional alkali pure from marine salt such that the price of it experiments and started the construction hi s industry . will not exceed that paid for the best foreign sodas). These events will now be discribed in detail. (b) 1779: Experiments of Athenas at Port de The earliest practicable process presented to the Croisic, August 16, in the presence of Pierre-Clement Academie, was developed by a Benedictine abbe. Grignon ( 1723- 1784 ), after verification during 1778 Pere Malherbe, who in 1777 succeeded in converting and 1779 of the experiments of Pere Malherbe by sodium sulphate into soda using charcoal and iron Pierre Joseph Macquer (1718-1784) and de Montigny. scrap. Malherbe' s method was based on the reduction (c) 1782: Memoir sent by Guyton de Morveau on of sodium sulphate to sulphide by fluxing with February 16 to the Controleur Gerzeral des Finances. charcoal in a reverberatory furnace. Iron scrap was A fifteen-year privilege granted to Athenas and added then and the final mixture consisted of a mass associates (Jourdan and La Bernardiere) to establish a of ferrous sulphide and caustic soda, formed by the factory for the manufacture of artificial soda near action of oxygen in the fire gases. The solid residue Nantes. was cooled, exposed to the air until it crumbled and (d) 1783: Establishment by Louis XYl of the Alkali then lixiviated to extract the soda. The solution was Prize to be awarded that same year in Saint-Martin. A sold as such or evaporated to produce impure sodium fifteen-year privilege granted on September 23, to carbonate. In order to commercialise hi s process Hollenweger conditioned to hi s installing his industry Malherbe entered in association with an entrepreneur near Nantes, and chemical artisan named Athenas, probably from (e) 1784: First experiments by Nicolas Leblanc, Le Croisic, who performed additional research and former surgeon and chemist, assigned by the Due de found that the iron scrap could be replaced by iron Chartres to give at the Royal Palace a course on ores, brought directly from the mines, or by vitriol chemistry applied to industry martial (copperas or ferrous sulphate) obtained from (f) 1788: Decree of August 23, revoking the the peat bogs of Brittany. Replacement of the scrap by privileges granted to Athenas, Guyton de Morveau, ores had the advantage of eliminating the need for and Hollenweger, because they had failed to establish sulphuric acid, which was both expensive and likely their industry within the time allotted for this purpose. to be unobtainable whenever the supply of saltpetre 11 Granting of a new privilege to Guyton de Morveau was pre-empted by military requirements . and the Marquis de Bullion to establish artificial soda Athenas' procedure was based on heating ferrous manufacturing facilities in Brittany, Poitou, Aunis, sulphate to a red heat, adding sodium chloride, and Saintonge, and maritime Flanders. continuing the heating process until hydrogen (g) 1789: Publication of a preliminary speech by chloride was liberated and sodium chloride converted Jean-Claude La Metherie (1743-1817) and deposition into sodium sulphate. Charcoal was now added and in the hands of Amedee-Barthelemy Berthollet (1748- the mass heated further until fusion. In Darcet's 1822), on March 4, of a memoir by Jean-Antoine words: "\'oxide de fer repasse a l'etat metallique et se Carny ( 1751-1830) and Geraud de Fontmartin recombine avec le soufre," (Iron oxide converts into describing two manufacturing processes, in addition the metal and then combines with sulphur). to Leblanc's experiments, repeated at the request of Afterwards, the mass was withdrawn from the furnace the Due d'Orleans, at the chemistry laboratory of the and the soda obtained as in the original Malherbe 11 22 College de France, under the supervision of Jean method ' • Darcet ( 1725- 180 l) and Jerome Dize. Malherbe's association with Athenas was (h) 1790: On March 27, a month after the signature unsuccessful and Athenas proceeded ahead alone: by of an first agreement in front of Jacques Lutherland, a 1794 he was already manufacturing small amounts of notary, where the Due d' Orleans was staying soda. In addition to Athenas' , two other factories were after the October events. Leblanc deposited in the also producing soda by similar procedures. One was hands of the notary Brichard a package containing the located at the Compagnie de Saint Gobain and the description of two new procedures, one for the other at Javelle. The Javelle facility, which was conversion of marine salt to soda and the second a directed by Alban, not only produced sodium personal letter to Dize, for the manufacture of lead carbonate but also sold the hydrogen chloride to the white (together with a favourable report by Darcet). In bleaching industry as a source of .

105 Educator Indian J. Chem. Tec hno!. , January 2003

About 1777 Jean Claude de Ia Methiere ( 1743- gradually developed on the surface. According to 18 17) proposed to fu se sodium sulphate with coal, Guyton de Morveau their method dupli cated that extract the carbonate from the product, and use the employed by nature in producing an efflorescence of su lehur dioxide released to manufacture sulphuric soda on the surface of mortar in certain cell ars ac id for converting the sodium chloride into sulphate. and in the dried residue of saline lakes and springs. In De Ia Metheri e's process was a theoreti cal one, which this process quicklime was slaked in water and th en Loui s-Jacques Thenard ( 1777-1857) et al. described mixed with a saturated brine solution. The mi xture 23 as fo ll ows : "There is a sure way of reali zing the was concentrated to a paste and left exposed to the air decomposition of marine salt although it may be in some closed and humid pl ace, preferabl y a cell ar. expensive. It will be done in equipment appropriate Sodium carbonate would th en form on the surface of fo r pouring sulphuric acid on marine salt, th e marine the mass. When it was removed another layer would acid (HCI) will be released and coll ected whi le the form and the process would be repeated until th e residue will be sodium sulphate of Glauber's salt. materials were exhausted. For this process Guyton de 11 1 This salt will be decomposed by calcinati ons with Morveau received a privilege dated June 3, 1783 c . charcoal. Sulphuric acid will be released as sulphur Another privilege was granted to Ho ll enweger. a dioxide and the residual material will be pure sodium former arti san at the royal glass factory. carbonate. It will be di ssolved in water and then Hollenweger's process first converted G lauber's salt crystalli zed. The sulphuric dioxide may be into sodium sulphide by incineration with powdered reconverted into sulphuric acid. It is possible that charcoal and then deri ved soda from th e sulphide. sulphuric ac id will not be transformed into sulphur Throughout the 1780's the Bureau du Commerce diox id e at aiL part of it will be transformed into under Jean-Fram;ois Tolozan's ( 1722- 1802) sulphur, which will fo rm a hepar (the name given by administration had sought to bring about such alchemi sts to an alkali sulphide). or any developments. In 1790, a year before Leblanc vegetable acid will decompose this hepar yi elding received his patent, Tolozan wrote 11 that ''Ia sodium acetate. Heating the latter will yield sodium fabrication de Ia soude avec le sel marin n 'est pas un carbonate in a pure form, but this will mean the loss secret aujord'hui," (Nowadays, the manufacture of of th e vegetabl e acid" . soda from marine salt is not a secret). It is 23 On the report written by Thenard et a/. it is said nevertheless, doubtful whether those that succeeded that if de Ia Methiere had tried the experi ence he did so as a result of this official encouragement. proposed he would have found that the reaction One of the larger producers of arti fic ial soda was between sodium sulphate and carbon did not yield Jean-Antoine Chaptal ( 1756-1 832), who in his sulphur di oxid e and pure sodium carbonate, the chemical factory at Montpelli er exploi ted th e reacti on sulphate was actuall y converted into a sulphide. In of salt and litharge (lead oxide). The method was very addi ti on, th e vegetable acid he recommended as a simple, but because of the cost of litharge, it was also puri fy ing agent would be indispensable for the total very expensive. A brine solution was poured into the soda to be obtained because the sodium sulphide litharge in great earthen contain ers, in suffi cient produced could be converted economi call y into amount to form a paste. The mass was stirred and sodium carbonate onl y with the help of carbon additional brine was added from time to time for dioxide. twenty-four hours. The products were lead In 178 1 Bryan Hi ggins (1737-1 8 18) patented in oxychl oride and causti c soda, which was separated by London a process similar to that of Malherbe, where li xiviation, re-crystallized and allowed to take up he first melted sodium sulphate with charcoal and from the atmosphere. The lead then mi xed it with iron or other metals. A day after oxychl oride could be used for pi gment, either directl y Hi ggi ns' patent, A. Fordyce proposed a similar as yell ow lead, or, converted in to lead sulphate by process. but suggested that iron oxide, the calx of dilute sulphuric acid, as white lead. This method had iron, be used instead of metallic iron. been used for some time in England where it was Guyton de Morveau and Carny erected a factory worked for yellow lead rather than soda as the . . I d 1114 for making soda by a process based on Scheele's pn nctpa pro uct . observation that when a mixture of common salt and In practice, none of the plants buiit for the lime was exposed to air, an effl orescence of soda application of the variot: s processes were successful.

106 Wisniak: Sodium carbonate Educator nor there were in a position to produce soda ash at a Leblanc deposited a sealed description of his price that could compete with potash. Their operating process with a notary on March 27, 1790, and was cost was very high and attempts to cheapen the awarded a patent on September 25, 1791. The product by replacing salt with sodium sulphate, soap essential features described in the patent were as leys, or kelp liquors (both of which had a high salt follows: One part of Glauber salt, one-half part of content) could only be justified on the basis of lower , and one-quart part of charcoal were taxes or no taxes at all. In addition, they were crushed and mixed between iron rollers. The mixture inappropriate for large-scale manufacture, they were was then spread out in a reverberatory furnace, the hard to operate, their yield was low, generated much working holes closed, fire was applied, and the waste of difficult disposal, and the end product was of mixture heated until fusion. The reaction took place re Iat1ve . Iy Iow qua I"1ty II ·14 . only after the mixture had acquired a semi-paste Leblanc's process, though only partly original, consistency; after that the rate was very fast. The overcame most of these defects and became the first mixture began to froth releasing a flammable gas, and really efficient artificial-soda process. finally became converted into soda. During all th ese processes it was necessary to stir the mass frequentl y. The operation was considered completed when gas Leblanc's process release stopped. The final fused material was called La Methiere's impractical process suggested to black ash it had a complex composition that changed Nicholas Leblanc, about 1787, the real solution of the rapidly in contact with air. The black ash was problem. The process he developed consisted of a first lixiviated with water yielding a solid residue and a step for producing sodium sulphate by the reaction solution of sodium carbonate. On the basis of 100 kg between sodium chloride and sulphuric acid. per part, each batch produced about !50 kg of soda. Afterwards, the sulphate was reduced with coal to the The main components of black ash were, approxi­ sulphide, which in turn was reacted with chalk or lime mately 41.6% weight sodium carbonate; 29.8% to form soda and calcium sulphide. The pertinent calcium sulphide, 11.6% calcium carbonate, and 4.4% chemical reactions are: coke. In the beginning of the implementation of the 2NaCl + H S04 ~ Na S0 + 2HCI ... (9) 2 2 4 process the black ash was sold as such directly to soap Na S0 ~ Na S (10) 2 4 + 4C 2 + 4CO boilers and other users. Na 2 S + CaC03 ~ Na 2C03 +CaS .. . (11) The reactant proportions given in Leblanc's patent were based on a series of wrong assumptions; it was Successive descriptions of Leblanc's procedure assumed that they represented the actual number of make it possible to follow the development of his molecules taking place in the reaction making process in three well-defined steps from the abstraction of the facts that the charge did not melt laboratory to the industrial stage. In the beginning totally and that it was well mixed. In addition, it was Leblanc carried out the transformation of sodium assumed that calcium sulphide is totally soluble in sulphate to soda in crucibles because he had not found water and that the ashes contained calcium yet the best proportions of sulphate, limestone, and oxysulphide, assumed to be in soluble in water. charcoal; and had not made any progress with the The reactions occurring during the process were preliminary conversion of sodium chloride to sodium interpreted in different ways. The original proportion sulphate. By the time he applied for a patent on July between the reacting compounds was based on the 15, 1791, he had already perfected a reverberatory false hypothesis that one of the products, calcium furnace for the second reaction, converting sulphate to sulphide, was soluble in water (it was mistaken with soda, and he had come very close to determining the calcium hydrosulphide) and that the ashes contained a optimum proportions between the reactants. It should calcium oxysulphide, 2CaS.CaO. Jean Baptiste Andre be remembered that Leblanc's invention, strictly Dumas (1800-1884) first attempted to explain the speaking, is limited to this second reaction, which in reaction in the black-ash furnace starting from the the parlance of the industry came to be called the wrong assumption that calcium sulphide was readily black-ash process. He had also been working in the soluble in water. This assumption was based on the 1 4 first reaction, later called the salt-cake process 1.1 • observation that neither hydrogen sulphide nor

107 Educator Indian J. Chern. Techno!., January 2003 ammon1um sulphide were capable of causing Although Leblanc was not deprived of his patent, he precipitation in a solution of . He lost the privilege of keeping it secret. As a then argued that if calcium sulphide were present in consequence, it began to be used by others in France black ash, th e subsequent lixiviation with water would and abroad, without licensing fees. set up a reaction between the calcium sulphide and Leblanc spent nearly eight years suing for sodium carbonate: ownership of his plant and pet1t1oning for reimbursement for the losses he had incurred. He 0 00 (12) finall y regained control of the plant in 180 I, but was From thi s fact Dumas inferred that the actual unable to raise the money to operate effectively. He in soluble salt was calcium oxysulphide, 2CaS.CaO. went into debt, grew depressed, and committed This calcium oxysulphide was assumed to be suicide in 1806. insoluble in water to account for the retention of Following the publication of Leblanc's process. sulphur by the insoluble residue and the non­ other alkali works were opened in , Di euse, appearance of sodium sulphide in the water used for Chauny, Marseilles, and other French cities. These lixiviation. Dumas represented the initial and final works prospered and while war lasted, the secret was stages of the reaction according to: held in France. After the peace of 1802, William S. Lash, of Walker-on Tyne, Englan~ l3jsited France. 2No 2 S04 + 3CaC03 + 9C ~ 2Na 2 C03 + Ca0.2CaS learned the details of the and in 181 4 +lOCO 000 (13) used the process to make small quantities of soda in Eventu<'tlly it was shown that calcium sulphide is England. (1793-1886), who was actually insoluble in water and that the residue left making prussiate of potash, , and solvents in after lixiviation was a mixture of calcium Dublin and afterwards in , hired in 1828 J. monosulphide and carbonate. In this manner, it C. Gamble (1776-1848), a Glasgow-trained chemist, become understood that the froth produced during the and began making soda on a large-scale plant in reaction was due to the release of carbon monoxide Liverpool. Though Muspratt was able to produce and that this gas burned with a yellow flame because good-grade material at a competitive price hi s sales of the sodium present. were almost nil at first. Soap makers accustomed to The three main reactions are considered to be: working with barilla, distrusted the new product and would have nothing to with it. Muspratt , therefore. (14) Na 2 S04 + 2C ~ Na 2 S + 2CO had to give away his soda free at first to convince

Na 2 S + CaC03 ~ Na 2 C03 +CaS (15) buyers of its quality. Once the prejudice had been overcome, and soap making recipes had been adapted Na 2S + CaC03 + C ~ CaO + 2CO ( 16) to the new material, demand for Leblanc soda rose 3 14 The action of water on black ash during lixiviation quickl/ ' . involves a series of complex reactions, of which the In 1825, ( 1768- 1838), a 111a1n IS: manufacturer of bleaching powder, initiated the manufacture of Leblanc alkali at Glasgow.

2CaS + 2H 0 ~ Ca(SH) + Ca(OH) 00 0 ( 17) 2 2 2 Initially, expansion of the industry in Britain was !n the same year that Leblanc was granted a patent, greatly hindered by the high revenue tax of thirty and after Darcet had made a favourable report in pounds charged on every ton of common salt used 1790, a plant was built at Saint-Denis in France, under (Salt Act). Abolition of this tax thirty years later. led the patronage of the Due d ' Orleans (1747-1793). England to be the world leader in soda production. the Leblanc's plant did well until 1793, when the Due industry grew steadily and by the middle of the d'Orleans was guillotined in the revolution and the eighteenth century it occupied a strategic position in plant confiscated and sold piecemeal by public the economy. In 1862 it consumed nearly two million auction. The total production of Leblanc's factory tons of raw materials, produced about 280,000 tons of amounted to only 15 tons of soda. finished product and occupied about 19,000 people . I . d' I J? 14 In 1794, a government commission published and d1rect y or 111 1rect y -· . publicized a report on all the available methods of The location of alkali manufacture was determined making so d a, me0 I u d'mg L e bl anc ' s process II ·23 . partly the location of the main users of its products

108 Wisniak: Sodium carbonate Educator and partly by a need to minimize the heavy transport basic chemistry remained the same: common salt, costs associated with bulky raw material inputs in the sulphuric acid, charcoal, and limestone were used to form of salt, pyrites, coal, chalk, and limestone. produce cheap sodium carbonate. The process Germany followed soon afterwards with the first required large amounts of material; in order to Leblanc factory at Schonebeck, near Magdeburg produce one ton of carbonate six tons of raw material making 200 tons/year by 1843, and another small were required and produced thirteen tons of solid, plant built near Cassel soon afterwards. Numerous liquid, and gaseous refuse, all of which had to be alkali plants were erected in other parts of Germany at disposed of in some way. Two of the by-products a later date, while in Austria, by 1856, three large were particularly harmful and contaminating: one plants were operating in Moravia, Silesia, and Aussig. gaseous (hydrogen chloride) and one solid (calcium It took more than a generation for Leblanc's sulphide). Production of one ton of sodium carbonate di scovery to change the situation of the soda market generated about 0.75 tons of HCI and two tons of si tuation. Fifty years after Leblanc's suicide, his sulphide. procedure had been adopted by all the European soda Other important disadvantages of the process were manufacturers and had produced about 300,000 related to waste of valuable chemicals: sulphur from ton/year of different alkalis. the sulphuric acid was confined in the calcium 24 Dumas wrote on this respect''- : "Depuis le sulphide and lost along the unreacted coal and commencement du siecle, toute I' industrie des limestone. The initial implementation of Leblanc's produits chimiques pivote autour des manufactures de process was also accompanied by the loss of most of soude artificialle et s'empare de leurs procedes our de the hydrogen chloride; a small fraction of it wa<; leurs produits" (After the beginning of the century, all recovered for the production of bleaching powder. It the chemistry industry pivoted around the fabrication took more than sixty years and stringent of artificial soda and took shelter on its procedures or environmental laws to increase the recovery to almost its products). one hundred percent. 2 1 Baud has remarked that an interesting economic Soon the owners of the land and forests and the aspect of the French facilities is that from 1810 on, farmers, started complaining about the damage; their the great soda factories of Ansel me Payen ( 1795- complain was strictly economical and not based on 1871) at Grenelle, of Pelletaz at Rauen, of Chaptal at social or environmental motives. Their main source of Ternes, La Folie, and Plan-d' Aren, of Carny at income was being affected negatively with the Dieuse, of Pluvinet at Rassuen, and of the Compagnie corresponding decrease in income. The main result de Saint Gobain at Charles-Fontaine, presented all the was to put the two classes, the traditional agricultural characteristics of the large capitalistic industries: one (represented in the House of Lords) in conflict technical and financial concentration. Two units were with the new one, formed by the new emerging class grouped together into one conglomerate: the glass of industry men (represented in the House of industry that received sulphur and salt and 14 25 Commons) ' • manufactured sulphuric acid and alkaline sulphate, In the beginning hydrogen chloride wa<; simply and the soda one proper that transformed the sulphate discharged into the atmosphere causing serious into carbonate. Sometimes the by-product of the glass environmental damage to humans, animals, industry, hydrogen chloride, was collected and employed in a third factory for the production of vegetation, forests, and buildings. Here the gas was chlorine for bleaching agents such as eau de Javel. susceptible to prevailing climatic conditions for in the The location of the industries was on the one hand presence of moisture it got converted rapidly into acid determined by the desire of obtaining a good price for rain. When the atmosphere was dry, the gas remained the raw materials and, on the other, of finding a at high altitudes and travelled great distance, but when regular outlet for the manufactured products. it was damp or foggy, it descended more rapidly to the ground. It soon became clear that these discharges 2 13 25 26 Environmental problem/ • • • were affecting plants, crops, and trees. The longevity Leblanc's process remained viable during 80 years of trees resulted in their continuous contact with acid until the advent of Solvay's process in 1863. During rain, until they became affected too. Buildings were this period it went through many improvements but its also affected and deteriorated.

109 Educator Indian J. Chem. Technol. , January 20()]

Several measures were taken to reduce environ­ The measures taken by the manufacturers to solve mental pollution, for example building very high the problem of obnoxious gases turned to their chimneys (150 meters tall) to disperse the gas at high benefit. Gaseous hydrogen chloride was transformed altitudes. Although this solution diluted the effluent, it into a liquid solution that not only could be used as worsened the problem because it dispersed the gases such it also became a source of chlorine, which was over a much larger area. Attempts were then made to extensively required for the textile, , water conduct the gas into underground channels and treatment, and other industries as bleaching powder. cisterns, absorb it in water, and then discharge it into Way before chemists were aware that hydrogen the near river. This solution transformed a gaseous chloride could be reacted with oxygen and pollutant into a liquid one. transformed into chlorine. Scheele had already The problem of disposal of hydrogen chloride was suggested a procedure based on the oxidation with 19 eventually solved in 1836 by William 's dioxide • Between 1869-1870 Walter (I 799- I 877) invention of absorption towers in which Weldon (1832-1885) implemented the oxidation of the gas was absorbed in a stream of water flowing HCI using manganese dioxide. Weldon's process counter-current to the gas (this was the first practical transformed manganese oxide into manganese absorption tower). By using coke or other porous chloride, from which the dioxide could not easi ly be material the device was subsequently improved to the regenerated. point where emissions of gas could be virtually The manufacture of chlorine by this method may eliminated. be considered as one of the first exampl es of a 26 The public outcry was so strong that in I 862 it technical innovation produced by an ecological law . moved the House of Lord and then the House of Solution of the caused by the gaseous Commons to approve the first important law of effluents left still the problem of pollution by the solid environment protection, the Alkali Act that imposed effluent. As mentioned above, production of one to n on the manufacturers the obligation of reducing by at of soda left roughly two tons of residual mud least 95% the emission of hydrogen chloride into the containing calcium sulphide, calcium hydroxide, and atmosphere. Inspectors were appointed by the Board considerable amounts of small coal. Part of this solid of Trade and given rights of access. The law also residue was used to fill in ditches and marshes and called for the establishment of an organism for construct railroad embankments, but eventually it was controlling the carbonate manufacturing industry, heaped wherever spare land could be found and carrying the pertinent analyses, etc., a historical first increasingly came to dominate the landscape. Rain institution for pollution abatement. Although in gave place to hydrogen sulphide release giving very today's terms the Alkali law protected the inhabitants unpleasant smells. In the summer months, the solid and the environment, it was actually an economical residues released large amounts of hydrogen sulphide, measure intended to protect the property of with the corresponding noxious effect in the landowners, particularly that of large, wealthy neighbouring areas. In addition, during the rainy 26 landowners • season, the water wash of these residues generated The first Inspector was Robert Angus Smith (1817- large amounts of a yellow liquid that contained 1884), a sanitary chemist and pioneer of the scienti fie sulphur and calcium polysulphide th at leaked into the 20 analysis of air pollution, who did systematic analyses water sources and contaminated them . of the atmosphere and provided with valuable Dumping of the solid residue meant not only an information regarding rain acidity (Angus was the ecological problem but also the loss of all the sulphur first to use the term acid rain). An early difficulty was used in the Leblanc process. This was a serious the lack of an accurate, self-acting measuring economical drawback since sulphur was an expensive instrument to determine the amount of gas eliminated. raw material, imported mainly form Sicily, and Smith solved this problem and by 1864 the average essential for the fabrication of sulphuric acid. In or

110 Wisniak: Sodium carbonate Educator

different chemical processes developed were based on CaC03 ~ Ca0+C02 (25) the same principles: to transform the sulphur present CaO+ 2NH 4 Cl ~ NH +CaC/2 + H 2 0 (26) in the calcium sulphide slag (insoluble) into soluble 3 compounds. This was done by oxidation with Overall sodium utilization averages 70%. atmospheric oxygen, followed by lixiviation and A first inspection of the above reactions shows that using hydrogen chloride to precipitate the sulphur in Solvay's process is free of many of the practical the form of polysulphide and hyposulphite. problems posed by the Leblanc process. It uses In 1862 (1839-1909) devised a , lime and salt as raw materials and produces process that allowed recovering about one-third of the sodium carbonate and calcium chloride as products. su lphur. Mond's process was improved by A. Chance Although the by-product calcium chloride has not a and C. F. Claus between 1882-1927, and was used for very large market, it is not noxious as the wa-;te many years to obtain sulphur from natural acid gases, products of the Leblanc process and so the pollution rich in hydrogen sulphide. The basis reactions of the problem is minimal. In addition, the Solvay process Chance-Claus process are: requires less than half as much fuel ac;; the Leblanc process does. CaS +CO? + H 20 ~ CaC03 + H 2S (18) Although the Solvay process is clearly more CaS+ H S ~ Ca(SH) (19) 2 2 efficient than Leblanc's, its invention did not mean Ca(SH) 2 + C02 + H 20 ~ CnC03 + 2H 2S (20) the immediate demise of the latter. Full

2H 2S+02 ~ H 20+2S (21) implementation of Solvay's process took many years and in this period the Leblanc process continued to be The last reaction was performed in the presence of improved and transform the waste problem into a aluminium or ferric oxide as catalyst. The process profitable enterprise. In time, the profits from chlorine waste contained essentially no sulphur and consisted sales exceeded those from the sale of sodium almost wholly of calcium carbonate. carbonate. All these improvements did not avoid the The Chance-Claus process was totally dependent downfall of Leblanc's process and by 1915 sodium on the waste of Leblanc's process; hence it ceased to carbonate was being manufactured almost exclusively be viable after the Leblanc' plants were closed. by the Solvay process. Leblanc's procedure suffered from other problems: Today, soda ash continues to be manufactured by soda was recuperated from a very diluted solution the Solvay process in Europe. But in the U.S., mining because of the limited solubility of sodium carbonate of trona ore in Wyoming began increasing from 1960 in water. In addition to the high energy required to and has all but eliminated domestic production of concentrate the solution, the solid phase was not pure Solvay soda ash (see below). sodium carbonate, but its decahydrate (Na2C03. With the coming of large-scale electrical power I OH20). In other words, purchase of one ton of generation in the 1890's, the chloro-alkali industry sodium carbonate implied the simultaneous purchase was born. From this point on, the Leblanc-Deacon of 1.7 tons of crystallization water. In addition, the process became a major producer of chlorine used as carbonate carried sodium chloride as an impurity. bleach in the paper and textile industries. All these disadvantages encouraged ( 1838-1922) to develop and commercialize a Return to natural resources 27 procedure using ammonia to produce soda ash from Natural sodium carbonate deposits (trona, sodium salt and limestone. The first plant using the Solvay sesquicarbonate), were discovered in the U.S., near process was built in 1863; this process or variations of 51 Independent Rock, Wyoming, in 1835. Mormon it are in use in much of the world of the 21 century. pioneers used the salt of these deposits as early as The Solvay process is based on the fo llowing 1849 for laundry and medicinal purposes. Scdium reactions: carbonate brine was discovered in wells near Green River, Wyoming, in 1907. Eventually. the Wyoming NaCl + NH 3 ~ammoniated brine (22) trona deposits were shown to be the largest in the ammoniated brine + C0 ~ NaHC0 + NH Cl 2 3 4 world; it is estimated that about 47 billion tons of (23) identified soda resources can be recovered from them. _ __, 2NaHC03 Na 2 C03 + C02 + H 20 (24) The first large-scale mining operations began in 1953.

II I Educator Indian J. Chern. Technol., January 2003 with an annual capacity of about 270,000 ton. Large 6 Fernandez J, Revista Espaiiola de Historia de las Ciencias de sodium carbonate deposits have also been identified La Naturaleza y de La Tecnologia, 4, articulo n° I. 1998. 7 Wisniak 1, Indian J Chem Techno[, 8 (200 I) 518. in Sealers Lake, California. 8 Clow·A, The Chemical Revolution; A Contribution to Social More than sixty-two natural sodium carbonate Technology, chapter III, (Gordon and Breach. London). deposits have been identified in other countries, some 1992,65. of which have been quantified but are still utilized in 9 Clow A & ClowN L, Ann Sci, 5 (1947) 297. very small amounts. I 0 Stanford E C C, J Soc Arts, (1862) 185. II Gillispie C C, Isis, 48 ( 1957) 152. In California, sodium bicarbonate, sodium 12 Hardie D W F & Dav idson Pratt J, A History of Modem sulphate, potassium chloride, potassium sulphate, British Chemica/Industry (Pergamon Press, Oxford), 1966. borax, and other minerals are produced as co-products 13 Matthews M H, Ann Sci, 33 ( 1976) 371 . from sodium carbonate. In Wyoming, the co-products 14 Reilly D, Isis, 42 (1951) 287. 15 Scheffer H T, Ann Chemie (Liebig), 2 ( 1796) 91. are sodium bicarbonate, sodium sulphite, sodium 16 Bergman T, Ann Chemie (Liebig). II ( 1796) 43. tripolyphosphate, and chemical caustic soda. 17 Scheele C, Kong/ Vetenskaps Acad Handlingar, XI (1779). To understand the significance of the return to 158. natural sources of sodium carbonate, it can be 18 Duhamel H, Memoires de Ia Academie Royale des Sciences. mentioned that in the year 2000 the total world 233 ( 1767) 239. 19 Mellor J W, A Comprehensive Treatise on In organic and production of this commodity was 34,000 million Theoretical Chemistry, Vol II, 728 (Longmans, Green and tons, of which 23,500 million tons (68.7%) were Co, London), 1922. manufactured by synthetic methods. The U.S. 20 Guyton de Morveau, L B, Elements de Chymie, Theorique et produces 95.3% of the world natural sodium Pratique, dans 1111 Novel Ordre, d'Apres les Decouvertes Modemes Pour Servir aux Cours Publics de /'Acadbnie de carbonate output. Dijon, Dijon, Vol Ill, 197. In 1998, in terms of production, soda ash was the 21 Baud P, Revue Historique, 174 ( 1934) I. 1 ll h largest inorganic chemical of all domestic U.S. 22 Darcel J, Giroud A, Lelievre & Pelletier B, Ann Chim. 19 inorganic and organic chemicals, excluding (1797) 58. petrochemical feed stocks. Although soda ash 23 Thenard L J, Chevreul M E. Pelouze T J, Regnault V. Balas A & Dumas J B. Compt Rendu, 42 ( 1856) 553. represented only 2% of the total $39 billion U. S. non­ 24 Dumas J B, Compt Rendu, 42 ( 1856) 558. fuel mineral industry, its use in many diversified 25 Haber L F, The During the Nin eteelllh products contributed substantially to the gross Century (Clarendon Press, Oxford), 19.'i8. domestic product of the United States. In the year 26 Dingle A E, The Economic History Rev, 35 ( 1982) 529. 27 US Geological Survey, Soda Ash, Mineral Commoditv 2000 the U.S. distribution of soda ash by end use was Summaries, Wash ington, DC, January 2002. glass 50%; chemicals 27%; soap and detergents II%; distributors 6%; flue gas desulphurisation 2%; paper Notes 2%; water treatment I%; and miscellaneous uses I%. In 1746, John Roebuck ( 171 8-1 794) pioneered the lead chamber process for the manufacture of cheap sulphuric acid References in several ton quantities. Pliny, Natural History, Book XXXVI, English translation by 2 Jeremiah 2: 22: "For though wash thee with nitre. and take Eichholz DE (William Heinemann, London), 1942, 151. thee much sope, yet thine iniquity is marked before me. sa ith 2 Patterson T S, Proc Royal Phil Soc, Glasgow, 53 (1924) 113. the Lord". 3 Stem E in Encyclopaedia Biblica, edited by Mazar B, Tur 3 Proverbs 25:20: "As he that taketh away a garment in cold Sinai N H, Yeivin S, Vol 5, 9~9. Bialik Institute, Jerusalem, weather, and as vinegar upon nitre, so is the he that sin geth 1968. songs to an heavy heart". Here the writer is probably 4 Lucas A & Harris J R, Ancient Egyptian Material and referring to the neutralizing action of vi negar upon a clean Industries, Histories & Misteries of Man, Ltd, London, 1989. subject. • 5 Wagner R, Quimica Industrial y Agricola, edited by Roma J 4 Abraham Darby (1677-1717) resolved the fuel problem of (Barcelona) 1889: Translated from German by Nacente Y the metallurgical and allied industries replacing coal for Soler F. wood, and later on, by transforming coal into coke.

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