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Method for recovering sodium sulfate by utilizing sodium sulfate containing waste salt residue

A technology containing sodium sulfate and sodium sulfate, which is applied in the field of hazardous waste resource treatment, can solve the problems of high operation requirements, low product recovery rate, high treatment cost, etc., and achieve good environmental and social benefits, high product recovery rate, The effect of low running cost

Inactive Publication Date: 2019-05-03
ZHEJIANG SHENLIAN ENVIRONMENTAL PROTECTION GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It mainly solves the following problems currently existing: (1) It is difficult or incomplete to remove toxic impurities in waste salt slag containing sodium sulfate by conventional methods, and the by-products are difficult to reach industrial-grade product standards; (2) The technology is not mature enough, and the treatment The cost is high and it is not easy to promote; (3) The product recovery rate is low, the operation requirements are relatively high, and the stability needs to be improved

Method used

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  • Method for recovering sodium sulfate by utilizing sodium sulfate containing waste salt residue
  • Method for recovering sodium sulfate by utilizing sodium sulfate containing waste salt residue
  • Method for recovering sodium sulfate by utilizing sodium sulfate containing waste salt residue

Examples

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Effect test

Embodiment 1

[0023] Get 131t of waste cooking agent residue in the pulp production process of a paper mill, after analyzing the sodium sulfate content in the raw material residue is about 81.05% (wt%), the sodium chloride content is about 1.15% (wt%), and the organic matter content is about 10.67% (wt%) , the water content is about 5.17% (wt%), and metal impurities such as calcium and magnesium are 1.13% (wt%). Choose heat treatment-dissolving water washing-multi-stage purification and impurity removal-thermal evaporation, concentration and crystallization combined system process route for treatment.

[0024] After heat treatment (treatment temperature 300°C), after the decomposition of organic matter is completed, the liquid-solid ratio (v / w) of 8:1 is used for dissolution and water washing, and the solution is purified, impurity-removed and multi-stage filtered, evaporated, concentrated and crystallized to obtain about 104.1 tons of sulfuric acid The sodium product has reached the first-...

Embodiment 2

[0026] Get 357t of the waste coagulant residue of a certain textile factory, after analyzing the sodium sulfate content in the raw material residue is about 78.86% (wt%), the sodium chloride content is about 0.89% (wt%), the organic content is about 6.84% (wt%), and the moisture content is about 78.86% (wt%). About 9.90% (wt%), metal impurities such as calcium and magnesium 2.17% (wt%). Choose heat treatment-dissolving water washing-multi-stage purification and impurity removal-thermal evaporation, concentration and crystallization combined system process route for treatment.

[0027]After heat treatment (treatment temperature 650°C), after the decomposition of organic matter is completed, the liquid-solid ratio (v / w) of 3:1 is used for dissolution and water washing, and the solution is purified, impurity-removed and multi-stage filtered, evaporated, concentrated and crystallized to obtain about 276 tons of sulfuric acid The sodium product has reached the first-class product o...

Embodiment 3

[0029] Get 413t of waste coagulant residues from a certain dyestuff production enterprise. After analyzing the sodium sulfate content in the raw material residues is about 83.57% (wt%), the sodium chloride content is about 0.46% (wt%), and the organic content is about 7.15% (wt%). The content is about 8.10% (wt%), and metal impurities such as calcium and magnesium are 0.72% (wt%). Choose heat treatment-dissolving water washing-multi-stage purification and impurity removal-thermal evaporation, concentration and crystallization combined system process route for treatment.

[0030] After heat treatment (treatment temperature 500°C), after the organic matter is decomposed, it is dissolved and washed with a liquid-solid ratio (v / w) of 5:1. After the solution is purified, impurity-removed and multi-stage filtered, it is evaporated, concentrated and crystallized to obtain about 335 tons of sulfuric acid. The sodium product has reached the first-class product of category III in the st...

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Abstract

The invention discloses a method for recovering sodium sulfate by utilizing sodium sulfate containing waste salt residue. According to the invention, a combined process of heat treatment, dissolutionand water-washing, multistage purification and impurity removal, and thermal evaporation concentration and crystallization is adopted to treat waste salt residue with a main component of sodium sulfate. Through heat treatment, organic components in the sodium sulfate containing waste salt residue are completely degraded and decomposed under the condition of a high temperature; through dissolutionand water-washing treatment, waste salt components in the sodium sulfate containing waste salt residue are completely dissolved, and residual carbon black residue is removed through solid-liquid separation; through purification and impurity removal treatment, impurity components like metal ions in a salt solution are removed by adoption of technologies like chemical precipitation and filtration; and through thermal evaporation concentration and crystallization treatment, a clean salt solution is treated by adoption of a steam heating evaporation technology to obtain a sodium sulfate product. In the whole process, harmless treatment and resourceful utilization of the sodium sulfate containing waste salt residue are realized; the sodium sulfate product produced by using the process providedby the invention reaches the standards (GB / T6009-2014) of an industrial-grade anhydrous sodium sulfate product; economic benefits are improved; and environmental pollution is avoided.

Description

technical field [0001] The invention belongs to the technical field of hazardous waste resource treatment, and in particular relates to a method for recovering sodium sulfate by utilizing waste salt residue containing sodium sulfate. Background technique [0002] The amount of industrial waste salt generated by industrial production is about 1.2 million tons per year, and the total amount of industrial waste salt in the country is expected to reach more than 10 million tons. The main inorganic components in the by-product salt slag of chemical production are sodium chloride, sodium sulfate or their mixture, and also contain a small amount of organic matter. Wherein a kind of common salt residue is exactly waste sodium sulfate waste salt residue, and sodium sulfate content is not less than 70% (wt%), and this sodium sulfate waste salt residue contains part organic matter (2%~15% (wt%)), also There are some other inorganic impurities, phosphate, chloride, etc., and the organi...

Claims

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Application Information

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IPC IPC(8): C01D5/16
Inventor 王治军廖元双曾辉叶标彭秋燕郑细东
Owner ZHEJIANG SHENLIAN ENVIRONMENTAL PROTECTION GRP CO LTD
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