how to make ammonium thiosulfate

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Advantageously, calcium thiosulfate can be prepared from inexpensive raw materials, such as calcium oxide, sulfur, and oxygen. Sodium thiosulfate and calcium chloride were used in the Spanish Patent 245,171. 94.7 Due to complex-forming abilities with metals, thiosulfate compounds have also been used in commercial applications such as photography, waste treatment, and water treatment applications. The dry lime can also consist primarily of calcium hydroxide, also known as hydrated lime, which can be mixed with water to produce a lime slurry. The study provides: Details regarding latest innovations and development in Ammonium Thiosulfate Market and how it is gaining customer traction during the forecast period. 0000005247 00000 n The contained sulfur corresponds to two times the stoichiometric amount of calcium to correspond to about 25% calcium thiosulfate—this is about 10.5% S. The optimum reaction conditions of time and temperature for the production of lime-sulfur slurry were investigated. 24 grams of sulfur is charged into the stirred, slacked slurry prepared in Example 1. This indicated that the polysulfide was present in large excess throughout the reaction up to near the end of the reaction and oxygen is the rate-limiting agent. Smaller quantities were successfully produced in a laboratory autoclave under similar conditions of temperature, pressure and gas contact area to liquid volume ratios but with the capability of exploring higher pressures. The process steps can be accommodated in a single reaction vessel with the appropriate auxiliary equipment (pumps, piping, valves, heat exchangers, filters, controls, etc.) 9.0 This must ultimately be determined experimentally. In the next reaction step, the lime-sulfur slurry is oxidized to produce the calcium thiosulfate product. Citric acid and acetic acid are preferred. 0000004613 00000 n Slaking of CaO alone increases temperature of the initial raw materials to about 50–60° C. The Ca++ concentration stabilized after about 135 to 190 minutes at about 90–92° C. The next step of the process involves oxidation of lime-sulfur to the desired calcium thiosulfate. The oxygen used for the purpose of oxidizing can be supplied by atmospheric air or by an enriched oxygen supply source. 94.3 Long-term stability calcium thiosulfate was addressed. The reaction mixture will consume no more oxygen and no further heat is generated. 22.34 Evaluation of calcium thiosulfate slurries treated with an anionic flocculent, AE874, and slurries not treated were performed at pH values ranging from 6.0 to 10.5. Virtually all the polysulfide is oxidized to thiosulfate. Generally, the best performance was achieved when about 50–70 μg/g of flocculant-to-slurry was used. 92.9 Flocculants and coagulants have been used in conjunction with filter aids for hard to filter slurries. If this interface area is not adequate, the reaction will be slow leading to larger amounts of undesirable byproducts. The formulated amount of sulfur is added to the contactor/reactor 60 through line 3. Metal sulfides can form as a result of metal oxide impurities in the calcium oxide. This is advantageous in maintaining heat exchange efficiency and in avoiding or reducing the need to clean internal surfaces of the process equipment. It was found that increasing the temperature enhanced the filtration rate. 0000001330 00000 n 14.88 The reaction is exothermic and causes the temperature of the lime slurry to rise. Oxidation temperatures above 75° C. should be avoided when producing calcium thiosulfate solutions of 24% because of calcium thiosulfate decomposition losses. The reaction rate was found to be equivalent to that of pure oxygen when the partial pressure of the contained oxygen component was the same as the total pressure for pure oxygen. Publication Date: 08/18/1970 . Ammonium thiosulfate is a preferred source of sulfur in clear solution fertilizers because it allows for much higher nutrient analysis in finished blends than ammonium sulfate. Temperatures closer to 90° C. result in better reaction rates; however, higher temperatures result in increased formation of insoluble calcium sulfite resulting from decomposition of the calcium thiosulfate. The data is evaluated in Table 1 and further plotted in FIGS. It has been found that under controlled oxidation reaction conditions, as described herein, that this precipitated sulfur further reacts with the available unreacted calcium hydroxide to continue the lime-sulfur reaction during the oxidation reaction.

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