The production methods of ammonium sulfate mainly include:
1. Neutralization method: ammonia and sulfuric acid react in a saturated crystallizer (under vacuum or normal pressure) to generate ammonium sulfate crystals, which are separated by a centrifuge, the filter cake is dried to obtain the product, and the mother liquor is returned to the saturated crystallizer. The reaction is strongly exothermic, and the heat of reaction is used to evaporate water brought in by sulfuric acid or intentionally added to control the temperature. In the atmospheric saturated crystallizer, a large amount of air can be blown into the reaction mass to remove the heat of reaction. The method of preparing ammonium sulfate by washing ammonia in coke oven gas or coal gas with sulfuric acid also belongs to the neutralization method.
2. Gypsum method: natural gypsum or by-product gypsum reacts with ammonium carbonate solution to generate calcium carbonate precipitation and ammonium sulfate solution, and the calcium carbonate is separated by filtration. The ammonium sulfate solution is evaporated and crystallized, filtered with a centrifuge, the filter cake is dried to obtain the product, and the mother liquor is returned to the evaporator. In areas lacking sulfur resources but with natural or by-product gypsum resources, this method can solve the sulfur resource in the production of ammonium sulfate, and the by-product calcium carbonate can be used to produce cement, etc. The disadvantage is the high energy consumption. If the mother liquor of ammonium sulfate produced by production such as caprolactam needs to be made into a solid product, the method is the same as that of the latter stage of the method.
3. Recover sulfur dioxide to ammonium sulfate from the tail gas of sulfuric acid production: wash the tail gas containing sulfur dioxide with ammonia water to generate ammonium sulfite and ammonium hydrogen sulfite solution, then acidify this solution with sulfuric acid, and the released sulfur dioxide is liquefied to produce liquid sulfur dioxide product, or return to the sulfuric acid plant to make acid, and the remaining concentrated ammonium sulfate solution is evaporated, crystallized and dried to obtain the product.
Contact Person: Miss. Jessic
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