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Recovery and treatment method for alkali residues produced in soda ash production

A technology for recycling and processing alkali residues, applied in chemical instruments and methods, preparation/separation of ammonia, removal of solid waste, etc. It can solve the problems of high processing cost, poor quality and low added value of products, and reduce steam consumption , the effect of reducing the production load

Active Publication Date: 2018-09-04
山东海天生物化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of treatment idea can achieve the purpose of waste utilization, but these processes are generally difficult to implement, with complicated process steps, high treatment costs, low purity and poor quality of the prepared products, which can only be used for engineering purposes, and the added value of products is low.

Method used

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  • Recovery and treatment method for alkali residues produced in soda ash production

Examples

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Comparison scheme
Effect test

Embodiment 1

[0037] The alkali slag is centrifugally separated and dehydrated by a centrifuge until the water content is 45wt%, and the ammonia distillation reaction is carried out with the hot mother liquor at a temperature of 79°C in the ammonia distillation tower. The ammonium chloride content in the hot mother liquor is 3.0mol / l, and each mother liquor Add alkali slag to a dry basis of 0.10t, control the pH value of the liquid in the ammonia distillation tower to 8.5, and keep the excess ammonium chloride in the mother liquor; the bottom pressure of the ammonia distillation tower is 12kPa; the outlet pressure is -12kPa; the tower bottom temperature It is 100°C; the outlet gas temperature at the top of the tower is 78°C; the first mother liquor ammonia distillation time is 8 minutes; the ammonium chloride content in the semi-ammonium mother liquor after the mother liquor ammonia distillation is completed is 1.0mol / l.

[0038] The half-ammonium mother liquor after the mother liquor has be...

Embodiment 2

[0041] The alkali slag is dehydrated by centrifugal separation and dehydration until the water content is 50wt%, and the ammonia distillation reaction is carried out with the hot mother liquor at a temperature of 80°C in the ammonia distillation tower. The ammonium chloride content in the hot mother liquor is 3.2mol / l, and each mother liquor Add alkali slag to a dry basis of 0.11t, control the pH value of the liquid in the ammonia distillation tower to 8.5, and keep the excess ammonium chloride in the mother liquor; the bottom pressure of the ammonia distillation tower is 15kPa; the gas outlet pressure is -12.5kPa; The temperature is 102°C; the outlet gas temperature at the top of the tower is 80°C; the first mother liquor ammonia distillation time is 6 minutes; the ammonium chloride content in the semi-ammonium mother liquor after the mother liquor ammonia distillation is completed is 1.2mol / l.

[0042] Transfer the ammonium semi-ammonium mother liquor after ammonia distillati...

Embodiment 3

[0045] The alkali slag is centrifugally separated and dehydrated by a centrifuge until the water content is 55wt%, and the ammonia distillation reaction is carried out with the hot mother liquor at a temperature of 82°C in the ammonia distillation tower. The ammonium chloride content in the hot mother liquor is 3.5mol / l, and each mother liquor Add alkali slag to a dry basis of 0.12t, control the pH value of the liquid in the ammonia distillation tower to 9.0, and keep the excess ammonium chloride in the mother liquor; the bottom pressure of the ammonia distillation tower is 16kPa; the outlet pressure is -13kPa; the tower bottom temperature It is 104 DEG C; the tower top outlet gas temperature is 82 DEG C; the first mother liquor ammonia distillation time is 5 minutes; the ammonium chloride content in the semi-ammonium mother liquor after the mother liquor ammonia distillation is finished is 1.45mol / l.

[0046] Transfer the ammonium semi-ammonium mother liquor after ammonia dist...

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Abstract

The invention discloses a recovery and treatment method for alkali residues produced in soda ash production. The recovery and treatment method comprises the following steps: (1) subjecting alkali residues to separation and dehydration, then subjecting the alkali residues and hot mother liquor to an ammonia distilling reaction in an ammonia distilling tower, controlling the pH value of liquid in the ammonia distilling tower to be 9.0 or below, and maintaining excess ammonium chloride in the mother liquor; (2) conveying semi-ammonium mother liquor obtained after ammonia distillation of the mother liquor in the step (1) to another ammonia distilling tower, and adding lime milk for ammonia distillation, wherein 0.13-0.19 m<3> of the lime milk is added into each cubic meter of the semi-ammoniummother liquor, and ammonia distillation is continued until the ammonia index of waste liquid in the tower is less than 50 mg / l; and (3) subjecting the waste liquid of secondary ammonia distillation to solid-liquid separation, dehydrating the alkali residues and conveying ammonia gas distilled from the tops of the ammonia distilling towers in two ammonia distillation operations to an ammonia absorption tower for recovery. According to the treatment method for the alkali residues in the invention, after the alkali residues are subjected to the secondary ammonia distillation reaction, about 80-85% of the solid has been involved in the chemical reaction; and after dehydration, the amount of the solid (wet basis) is reduced to less than 12.3% of the amount of the solid before ammonia distillation.

Description

technical field [0001] The invention relates to the technical field of treatment of three wastes in chemical production, in particular to the treatment technology of alkali slag in soda ash production. Background technique [0002] In the production of soda ash by the ammonia-soda method, a large amount of ammonia distillation waste liquid is produced in the ammonia recovery process, and the waste liquid carries a large amount of alkali slag. At present, there is no economical and effective treatment method for alkali slag in the world. Most of the known technologies use the method of transporting the waste liquid to the slag yard, natural settlement of the alkali slag, and stacking for storage. Because the solid particles of the alkali slag are extremely small, with an average particle size of 10 μm, it is determined that the alkali slag will naturally settle down to 80% of the water content, and will not continue to settle. Therefore, this treatment method occupies a larg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01C1/02B09B3/00C01B33/18C01F11/46
CPCC01B33/18C01C1/026C01F11/46B09B3/80B09B3/40
Inventor 王笑镭张元德徐德升
Owner 山东海天生物化工有限公司
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