Combined production of alkali by using waste water

Abstract

A combined soda production with waste water is carried out by: 1) totally collecting waste carbureted ammonia water produced by melamine with constant pressure ammonium catalytic circulating method, ammonia content of carbureted ammonia water > 27%, carbon dioxide content > 33%, and water content < 40%; 2) separating dicarbonate to obtain mother liquor, making mother liquor I heat exchange with mother liquor II , and cold crystallizing separating out industrial ammonium chloride; 2) salting out semi-mother liquor II , adding sodium chloride, and salting out crystallizing separating to obtain agricultural ammonium chloride. It achieves low cost and no pollution.

Description

technical field [0001] The invention relates to a new route for alkali production, in particular to a method for joint alkali production using waste water, which belongs to the technical field of chemical manufacturing technology. Background technique [0002] At present, the soda-making process in our country is relatively developed, and the total output ranks first in the world, but the process is very complicated. In summary, there are the following types: one is trona, the other is nepheline soda, the third is mirabilite soda, and the third is ammonia. Soda production by soda method, four-combination method (Hou's soda production method) soda production, and the fifth is gas-changing soda production. The above alkali-making methods except natural ones have relatively high processing costs. Taking the combined alkali method as an example, since its ammonia and carbon dioxide come from a synthetic ammonia plant, the cost of this piece is relatively high, and it needs 2 tim...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the defects of high cost, long and complicated process route and melamine production tail gas in the existing soda production process, especially the difficulty in the treatment of carbonized ammonia water and low benefit of the normal pressure full ammonia catalytic circulation method, and propose a brand-new The method of producing soda ash from melamine wastewater using the atmospheric pressure full ammonia catalytic cycle method shortens the process flow, saves electricity and steam consumption, and greatly reduces production costs

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