US 2011 O2623.43A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2011/0262343 A1 Hojjatie et al. (43) Pub. Date: Oct. 27, 2011 (54) PROCESS FOR PREPARATION OF CALCIUM Publication Classification THIOSULFATE LIQUID SOLUTION FROM (51) Int. Cl. LIME, SULFUR, AND SULFUR DIOXIDE COB I7/64 (2006.01) (52) U.S. Cl. ........................................................ 423/514 (75) Inventors: Michael Massoud Hojjatie, Tucson, AZ (US); Yelena Feinstein, (57) ABSTRACT Tucson, AZ (US); Constance Lynn An efficient batch or semi-continuous method of production Frank Lockhart, Tucson, AZ (US) of relative high concentration, low byproduct-containing, cal cium thiosulfate (CaSO) from lime, sulfur or calcium (73) Assignee: TESSENDERLO KERLEY, INC., polysulfide, and sulfur dioxide under elevated reaction tem perature conditions is described. The product is an emulsion Phoenix, AZ (US) of liquid calcium thiosulfate and solid byproducts. Under the conditions of the art, including the mole ratios of lime to (21) Appl. No.: 12/764,843 sulfur, the temperature of the reaction process and the sulfur dioxide reaction conditions, including rate and duration, the (22) Filed: Apr. 21, 2010 byproducts are reduced to about 2% by weight. Recycled Sulfur Calcium Thiosulfate ---O-G)-GED-G-G) Patent Application Publication Oct. 27, 2011 Sheet 1 of 4 US 2011/0262343 A1 PROCESS KINETICS FORCATS PREPARATION FROM "TRUE CALCUM POLYSULFIDE" AND SO2 PHASA FUNCTION OF TIME l2 pro- p- --------------------- ... ------ --- -- - - -- m-- --- 3. 8 . se: ... "aggers. -x x w w w x * v- w r - - - - - - - - - - - im w w w w w w w w - Y, 1 it 6 --------------------------------------- s w \r --------- ---------- ry. & : 4 - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - sex Xx ... we w w - w w w x 3.x w w w w a “r w w w is iw w w on s. v . x X w. w; w x x ro w w w x wi a 1x w w w w w m m. m. w & w w w - x x n - a $x w w w w Y, m w w w it w x x . 2 : : 3. Ol --------- l 2. 3. SO O 8O time (min) +CaPS, undiluted () CapS, diluted is: CapS + Cats Figure 1 Patent Application Publication Oct. 27, 2011 Sheet 2 of 4 US 2011/0262343 A1 Fitration Recycled Sulfur Calcium Thiosulfate ---O-G). GED-G-G) Figure 2 Patent Application Publication Oct. 27, 2011 Sheet 3 of 4 US 2011/0262343 A1 H2O SULFUR Air H2S, SO2, N2 R-1 CALCIUMPOLYSULFIDE+ WENT CA.CUMTHOSULFA H2S, SO2 Scrubber SO2, N2 Figure 3 25% CALCIUM THiosulfate Patent Application Publication Oct. 27, 2011 Sheet 4 of 4 US 2011/0262343 A1 Acid & FlocCulant Sulfur Water Lime Figure 4 US 2011/0262343 A1 Oct. 27, 2011 PROCESS FOR PREPARATION OF CALCUM nitrate, due to the NO, or Cl anion presence, a more envi THIOSULFATE LIQUID SOLUTION FROM ronmentally-friendly counterion such as thiosulfate (S.O.') LIME, SULFUR, AND SULFUR DIOXIDE is desirable in the application of calcium fertilizer products. Calcium thiosulfate is referred to herein as "CaTs’. CaTs is a FIELD OF INVENTION registered trademark of Tessenderlo Kerley, Inc. 0001. The present invention is directed to a process for the 0010 Although calcium thiosulfate has been known for preparation of calcium thiosulfate, a plant nutrient solution. many years and has many references in the literature, there are Another aspect of the present invention is the removal of air not many known commercial methods that employ inexpen pollutant Sulfur dioxide from industrial plants producing it, to sive raw materials to produce high purity calcium thiosulfate with a low amount of byproducts and with solid residue of convert the sulfur dioxide to calcium thio Sulfate. insoluble calcium salts which permit easy separation from the DESCRIPTION OF RELATED ART calcium thiosulfate product. 0011 “Lime-sulfur is a commonly used term for a cal 0002. The thiosulfate ion, S.O., is a structural analogue cium thiosulfate and calcium polysulfide mixture resulting of the SO, ionin which one oxygenatom is replaced by one from reaction of lime and sulfur. Preparation of “lime-sulfur S atom. However, the two sulfur atoms in SO’ are not via boiling of Sulfur sludge from Sulfuric acid plant and lime equivalent. One of the Satoms is a sulfide-like sulfur atom is described by P. Sivaprasad (India Pat. No. 163510, May that gives the thiosulfate its reducing properties and complex 1987). ing abilities. (0012 U.S. Pat. No. 4,976,937 (Lee) describes a method for sulfur dioxide removal from flue gases with sulfite oxida tion inhibition. The presence of a small amount of thiosulfate, 0.008-0.3 wt %, in the wet scrubber inhibits the oxidation of f f sulfur dioxide to sulfates and therefore provides a scrubbing s==o K> silio system that is non-scaling for gypsum, i.e., that does not result O O in the buildup of gypsum scale. The 937 patent describes that a calcium thiosulfate and calcium polysulfide mixture results 0003. Thiosulfates are used in leather tanning, paper and from the reaction of lime and emulsified sulfur in the lime textile manufacturing, flue-gas desulfurization, cement addi slaking tank. It is mixed with Sulfites and bisulfites that origi tives, dechlorination, ozone and hydrogen peroxide quench nally formed in the wet scrubber in the recycling tank. Cal ing, coating stabilizers and so on. cium thiosulfate forms from the reaction of polysulfide, 0004. Due to these complex-forming abilities with metals, sulfites, and bisulfites at 82° C.-88° C. (180° F-190° F.) thiosulfate compounds have been used in commercial appli during 5-25 minute intervals. However, the concentration of cations such as photography, waste treatment and water treat calcium thiosulfate is only 0.3 wt %. ment applications. (0013 U.S. Pat. No. 3,644,087 (Urban) discloses a process 0005. Thiosulfates readily oxidize to tetrathionates and for the removal of sulfur dioxide (SO) from gas streams sulfates: containing SO and oxygen (O) by converting SO to the corresponding thiosulfate, whilst preventing the buildup of undesirable byproducts, e.g. Sulfates, which otherwise occurs 0006. Due to this transformation, thiosulfates are used as due to the reaction of oxygen from the input gas stream with fertilizers in combinations with cations such as ammonium, the water-soluble sulfite that is formed when the SO, is potassium, magnesium and calcium. The ammonium, alkali absorbed in the scrubbing solution. Urban's process involves metal and alkaline earth thiosulfates are soluble in water. adding a reducing agent Such as hydrogen sulfide, finely Water solubilities of thiosulfates decrease from ammonium to divided sulfur or an alkaline earth polysulfide into the gas alkali metals to alkaline earth thiosulfates, i.e. ammonium scrubbing Zone, wherein the scrubbing solution can be a thiosulfate has the highest relative water solubility and alka water-soluble alkaline earth hydroxide. Calcium hydroxide, line earth thiosulfates have relatively the lowest. which is only slightly water-soluble, is not listed as an 0007 Calcium is an essential plant nutrient. Calcium example for the scrubbing Solution. This patent does not availability is essential in the biochemistry of plants and, as relate to the production of calcium thiosulfate. recently discovered, improves the nitrogen fertilizer effi (0014 EPO 043.869A1 (Lee) discloses a process for ciency of surface-applied urea. This is not to be confused with removing SO from flue gases using an aqueous slurry of the role of important soil amendments such as lime or gypsum alkaline earth metal compounds, whereinthiosulfates are pro with the need of soluble calcium by high-value crops. Both duced and recycled for use in the process to inhibit the oxi are extremely important in soil fertility and plant nutrition and dation of sulfites (which forms undesirable byproducts that complement each other. cause buildup). Lee discusses that lime and emulsified Sulfur 0008 Calcium has been applied as a foliar agent in apple are reacted to produce calcium thiosulfate and calcium orchards as a preventive to a physiological problem known as polysulfide. One of Lee's preferred slurries of the alkaline “bitter pit” which is caused by calcium deficiency. Calcium is earth metal compounds is formed from a mixture of calcium also important to potato, tomato, lettuce, carrot, alfalfa and hydroxide and magnesium hydroxide. Lee is not concerned other fruit and vegetable production. Tomato plants with cal with producing calcium thiosulfate for recovery as a product. cium deficiency show severe infection with Fusarium (0015 U.S. Pat. No. 4,105,754 (Swaine, Jr.) describes the Oxysporum, the fungal pathogen that causes wilt and crown production of calcium thiosulfate by a metathesis reaction of rot in tomatoes. ammonium thiosulfate and calcium hydroxide or calcium 0009. Although soluble calcium could be attained from oxide. This approach requires constant removal of ammonia calcium nitrate, calcium chloride and calcium ammonium by air stripping at below the boiling point of the mixture and US 2011/0262343 A1 Oct. 27, 2011 capturing the gas. Further, not all the ammonia can be after chemical combustion processes, and (d) modification of removed by this process, and as a result, the resulting calcium chemical combustion processes. thiosulfate tends to have a lingering ammonia odor and/or 0025 Numerous methods have been developed to remove contamination with ammonia or ammonium thiosulfate. Sulfur dioxide for chemical combustion processes involving 0016 Japan Patent No. 6,039 issued in 1973 describes sulfur dioxide. The following are examples of such methods: preparation of calcium and magnesium thiosulfate by treating Absorption into dimethyl sulfoxide (DMSO, U.S. Pat. No. Sulfur and the corresponding Sulfite in an alkaline solution. 3.538,681), absorption in molten alkaline metals carbonate High yields only are obtained only with magnesium thiosul salts such as lithium, sodium, and potassium carbonate at fate. This patent also described the formation of calcium 1500° F-2000°F.