Process for recycling products from mother liquid containing ammonium chloride, sodium chloride, ammonium hydrogen carbonate and sodium hydrogen carbonate through thermal method

Abstract

The invention provides a process for recycling products from mother liquid containing ammonium chloride, sodium chloride, ammonium hydrogen carbonate and sodium hydrogen carbonate through a thermal method. The process comprises a method for recycling gas generated after deaminizing the mother liquid. The method for recycling the gas generated after deaminizing the mother liquid comnprises the following steps: preheating the mother liquid, then feeding the mother liquid into an ammonia still for deaminizing, feeding carbon dioxide and ammonia gas generated after deaminizing into an ammonia absorption tower for generating carbon-containing ammonia water, adding carbon dioxide into the carbon-containing ammonia water, enabling carbon dioxide in the carbon-containing ammonia water to be excessive and generate ammonium hydrogen carbonate. The process also comprises a method for recycling the deaminized mother liquid and obtaining ammonium chloride and sodium chloride. The method for recycling the deaminized mother liquid and obtaining ammonium chloride and sodium chloride comprises the following steps: carrying out five-effect cross-flow evaporation to obtain sodium chloride, carrying out four-effect flash evaporation and crystallization to obtain ammonium chloride, feeding salt thickener overflowing liquid and salt centrifugal machine post-throwing liquid into a V-effect evaporation tank and enabling the salt thickener overflowing liquid and the salt centrifugal machine post-throwing liquid to participate in circulation again; feeding ammonium thickener overflowing liquid and ammonium centrifugal machine post-throwing liquid into an IV-effect flash evaporation and crystallization tank by using a pump, and enabling the ammonium thickener overflowing liquid and the ammonium centrifugal machine post-throwing liquid to participate in production circulation again. The process is capable of simultaneously recycling to obtain ammonium chloride and sodium chloride; meanwhile, the recycling rate is extremely high; the process is also capable of effectively increasing the heat utilization rate.

Description

technical field [0001] The invention relates to the technical field of recovery of mixed mother liquor, in particular to a process for thermally recovering products from mother liquor containing ammonium chloride, sodium chloride, ammonium bicarbonate and sodium bicarbonate. Background technique [0002] Using brine and ammonium bicarbonate as raw materials to produce baking soda by metathesis reaction, in the production process, a large amount of mother liquor containing ammonium chloride, sodium chloride, ammonium bicarbonate, and sodium bicarbonate will be produced. In addition, the soda ash production process is obtained Heavy alkali filtration mother liquor (usually called soda ash production mother liquor) also contains the above four components, and its component content is slightly different from the mother liquor obtained after the above-mentioned metathesis production of baking soda (usually called baking soda production mother liquor) . [0003] At present, the a...

AI Technical Summary

Problems solved by technology

There are many disadvantages in this patent: 1. The ammonia water obtained by condensing the tail gas after deamination has low concentration and large equivalent, and the ammonia water contains a large amount of carbon dioxide, which has little practical value; 3. After the high-temperature mother liquor enters the final effect, the temperature drops rapidly, and the secondary steam generated cannot be reused, and the heat utilization rate is not high; 4. Multi-stage pre-heating is adopted in the process. The heat exchange of the heat exchanger, especially the condensate water preheater, has a limited effect, but it will increase the frequency of mother liquor clogging, which is not feasible in the actual industrial production process