Method for producing ammonium sulfate by using calcium sulfate waste residues produced in lactic acid production

Abstract

The invention discloses a method for producing ammonium sulfate by using calcium sulfate waste residues produced in lactic acid production, which comprises the following steps of (1) preparing raw materials of water, the calcium sulfate waste residues and ammonium bicarbonate, enabling ratio of amount of substance of the calcium sulfate (counting according to calcium sulfate content in the calcium sulfate waste residues, and the same below) and the ammonium bicarbonate to be 1: (0.9-1.2), and enabling granularity of the calcium sulfate waste residues to be larger than or equal to 80 meshes; (2) adding the water and the ammonium bicarbonate in an agitated reactor, stirring to enable the ammonium bicarbonate to be completely dissolved, and enabling mass fraction of the ammonium bicarbonate in the solution to be 20%-30%; and (3) controlling the temperature of the solution in the agitated reactor to be 20-30 DEG C, adding the calcium sulfate waste residues during stirring and reacting for 0.5-3 hours; adding ammonia water continuously in a reaction process to adjust the potential of hydrogen (pH) of the solution in the agitated reactor to be 8-10, and keeping until the reaction is ended. The method can reduce ammonia water use level, improve percent conversion of the calcium sulfate in the calcium sulfate waste residues and yield coefficient of ammonium sulfate, and be applicable to production of the ammonium sulfate of manufacture enterprises by comprehensively using the calcium sulfate waste residues.

Description

Technical field [0001] The invention relates to the conversion and utilization of calcium sulfate waste residue produced in the production of lactic acid, and particularly relates to a method for producing ammonium sulfate by using the calcium sulfate waste residue produced in the production of lactic acid. Background technique [0002] In the prior art, a large amount of calcium sulfate waste slag is generated in the production of lactic acid, and the calcium sulfate waste slag is usually sold directly (for example, to a cement plant), but the price is lower. Chinese patent document CN101284676B discloses the ammonium sulfate manufacturing process, which uses calcium sulfate as a raw material; however, there are the following technical defects in actual industrial production: 1. For lactic acid manufacturers, it is necessary to purchase ammonia and carbon dioxide as raw materials, and the storage of ammonia And transportation are very inconvenient; 2. The conversion rate of calc...

AI Technical Summary

Problems solved by technology

Chinese patent document CN101284676B discloses ammonium sulfate manufacturing process, which adopts calcium sulfate as raw material; but there are following technical defects in actual industrial production: 1, for lactic acid production enterprises, need to buy ammonia and carbon dioxide as raw materials, and the storage of ammonia 2. The conversion rate of calcium sulfate is low, resulting in low yield of ammonium sulfate. 3. A large amount of calcium sulfate is often trapped in the calcium carbonate produced by the reaction. volume increase