Method for recycling ammonium sulphate from waste mineral slag of electrolytic manganese metal

Abstract

The invention discloses a method for recycling ammonium sulphate from waste mineral slag of electrolytic manganese metal. The method comprises the following steps of: carrying out heating reaction, iron removal, heavy metal removal, neutralization and filter pressing on the waste mineral slag slurry in the production of the electrolytic manganese metal to obtain 160 g/L to 200 g/L manganese sulphate solution, pumping the manganese sulphate solution accounting for 80% of the total volume of a crystallizing boiler, and carrying out the crystallization and purification on the manganese sulphate solution, wherein the crystallization and purification comprises the processes of crystallization, solid-liquid separation, dissolution, filter pressing and the like, recycling the excess heat by an auxiliary crystallization tower, reducing the temperature of the drained waste water from 210 DEG C to 80-85 DEG C, and then feeding the waste water to a waste water treatment tank; under a certain force of stirring, adding lime cream slurry and carrying out the replacement reaction on ammonium sulphate in the waste water and lime cream slurry to generate calcium sulphate and exhaust ammonia gas, and introducing ammonia gas to an ammonia spray tower to prepare ammonia. The invention adopts the method for recycling ammonium sulphate from waste mineral slag of electrolytic manganese metal, not only reduces the cost of production, but also improves the quality of product and has low energy consumption and no pollution to environment; and the three wastes discharge meets the national discharge standard of environmental protection.

Description

technical field [0001] The invention relates to a method for producing manganese sulfate, in particular to a method for recycling ammonium sulfate by electrolyzing metal manganese waste slag. Background technique [0002] The annual production capacity of electrolytic manganese metal in my country has reached 2 million tons. In 2007, the actual annual output was 1.2 million tons, and there were at least 10.2 million tons of manganese slag per year. The manganese sulfate solution is 2.55 million tons, the average manganese sulfate content in the solution is calculated as 110g / L (Mn40g / L), the average ammonium sulfate content is calculated as 120g / L, and the annual loss of manganese sulfate in the slag reaches 280,500 tons, (equivalent to manganese The amount of metal is 102,000 tons, which is equivalent to 680,000 tons of manganese carbonate with a Mn content of 15%. Ammonium sulfate is 306,000 tons. Ammonium sulfate cannot be recycled directly for the time being, only liquid ...

AI Technical Summary

Problems solved by technology

The production cost of each ton of manganese sulfate plant is calculated at 4,600 yuan, and the market price of per ton of liquid ammonia is calculated at 2,500 yuan, with an annual loss of 1.48 billion yuan and serious pollution to the environment.

Moreover, the production is restricted by the content of manganese ore: it is necessary to use high-grade manganese ore with a manganese content of more than 34% to produce products with a manganese content of 98-99%. Produce products with a manganese content below 96%; high production costs and high energy consumption: 1.2-1.5 tons of coal is required to produce 1 ton of manganese sulfate