New method for recycling ammonia distillation wastewater discharged during production of soda ash by virtue of ammonia-soda process

Abstract

The invention belongs to the technical field of wastewater treatment and provides a new method for recycling ammonia distillation wastewater discharged during production of soda ash by virtue of an ammonia-soda process. The new method comprises the following steps: clarifying the ammonia distillation wastewater, and filtering, so that clarified liquor and solid waste residue are obtained; adding excessive lime milk into the clarified liquor, carrying out causticizing reaction, and obtaining magnesium hydroxide floating on liquid surface and slurry after the causticizing reaction is finished; respectively adding the slurry and excessive refined mirabilite aqueous solution into a gypsum reactor, fully reacting, filtering products, and washing, so that a dehydrate gypsum filter cake and turbid liquid containing sodium chloride and calcium hydroxide are obtained; carrying out dust removal and desulfurization purification treatment on carbon dioxide waste gas, introducing into a carbonization tower, carrying out carbonation reaction with calcium hydroxide in the turbid liquid, settling, and filtering, so that a light calcium carbonate filter cake and sodium chloride clear liquid are obtained; and applying the sodium chloride clear liquid to an alkali making system, so that sodium chloride in the clear liquid is recycled. The new method provided by the invention solves the technical problem that waste produced in a soda ash production process by virtue of the ammonia-soda process in the prior art cannot be comprehensively utilized.

Description

technical field [0001] The invention belongs to the technical field of waste water treatment, and relates to a new method for recycling ammonia distillation waste water discharged from the production of soda ash by an ammonia-soda method. Background technique [0002] In 2016, the total output of soda ash in my country was 25.883 million tons. The soda ash production process has formed a production pattern dominated by ammonia-soda method and combined soda method, supplemented by natural soda method. The output of ammonia-soda method is slightly larger than that of combined soda method, accounting for about Half of the output, that is, the soda ash produced by the ammonia-soda method was close to 13 million tons in 2016. The ammonia-soda method has a long history of producing soda ash, mature technology, large-scale continuous production, high degree of mechanization and automation, high product purity, and good quality. It has great advantages in the coastal and salt lake are...

AI Technical Summary

Problems solved by technology

[0002] In 2016, the total output of soda ash in my country was 25.883 million tons. The soda ash production process has formed a production pattern dominated by ammonia-soda method and combined soda method, supplemented by natural soda method. The output of ammonia-soda method is slightly larger than that of combined soda method, accounting for about Half of the output, that is, the soda ash produced by the ammonia-soda method was close to 13 million tons in 2016. The ammonia-soda method has a long history of producing soda ash, mature technology, large-scale continuous production, high degree of mechanization and automation, high product purity, and good quality. It has great advantages in the coastal and salt lake areas of our country, but the huge amount of waste liquid, waste residue, and carbon dioxide waste gas produced by the ammonia-soda method of producing soda ash not only caused a huge waste of resources and energy, but also brought serious hidden dangers to the environment. and pressure, which is an important reason why the development of soda ash produced by the ammonia-soda method is severely restricted

[0004] Therefore, during the production of soda ash by the ammonia-soda method, wastes such as ammonia distillation waste liquid, Glauber's salt waste liquid, milk of lime and carbon dioxide waste gas are produced, and these wastes are directly treated and discharged. Not only the waste treatment process will consume a lot of manpower and material resources, but also Calcium, magnesium, and sodium are also wasted in vain. Therefore, actively exploring new processing methods to make comprehensive utilization of resources has become an important and urgent task for enterprises and R&D institutions.

Images