Treatment process of sodium chlorate chromium-containing salt mud

Abstract

The invention discloses a treatment process of sodium chlorate chromium-containing salt mud. The method comprises the following steps of (1) dissolving the chromium-containing salt mud; (2) detoxifying a chromium mud solution; (3) cleaning and performing solid-liquid separation; (4) re-dissolving a filter cake and performing solid-liquid separation; and (5) detecting solid waste residues. The method has the advantages that (1) chromium in the chromium-containing salt mud can be recovered only by adding raw material hydrochloric acid required by a sodium chlorate production system, and the recovered chromium returns to the sodium chlorate production system for recycling because no new impurity is introduced; (2) the process steps are simple, the control is facilitated, excessive equipment does not need to be arranged additionally, and the equipment investment cost is reduced; (3) recycling of hexavalent chromium and washing water in the chromium-containing salt mud can be realized whiletreating the chromium mud; and (4) solid waste residues generated after the treatment meet the solid waste filling standard, and the secondary pollution to the environment is avoided.

Description

Technical field: [0001] The invention relates to a treatment process of chromium-containing salt mud, in particular to a treatment process of sodium chlorate-containing chromium salt mud. Background technique: [0002] In the production process of sodium chlorate, in order to catalyze the main reaction, reduce the amount of oxygen generated, and control the pH value in the electrolytic cell, it is necessary to add sodium dichromate to the system; every ton of sodium chlorate needs to add sodium dichromate about 0.118 kg. At the same time, in the production process of sodium chlorate, in order to remove calcium ions, magnesium ions and sulfate ions in the raw salt, it is necessary to add sodium hydroxide, sodium carbonate, calcium chloride to the production system, and remove calcium ions, magnesium ions and sulfate ions Ion precipitation; during this process, the chromium ions added in the production system in the form of sodium dichromate and calcium chromate enter the cla...

AI Technical Summary

Problems solved by technology

However, due to the various forms of chromium ions in waste salt mud, including free, adsorbed, and wrapped, simple washing can only remove free chromium ions, but cannot remove chromium that exists in the form of adsorption and wrapping. ions; if the chromium ions in the form of adsorption and encapsulation are not treated, the residual Cr in the waste salt mud 3+ It will be oxidized to Cr as the environment changes 6+ , resulting in the difficulty of detoxifying chromium ions in waste salt mud and the problem that it cannot be completely removed, causing continuous pollution to the surrounding ecological environment, and causing great harm to the ecological environment and people's health

[0004] Patent CN201710765313.X discloses the treatment process and system of waste salt mud in the production of sodium chlorate. Although a good treatment effect is achieved, the treatment process needs to grind the salt mud particles, and at the same time, it needs to add an oxidant to reduce Cr 3+ Oxidized to Cr 6+ , and then add dissolution agent, the Cr 6+ Dissolve in solution, then add reducing agent to Cr 6+ Converted to chromium hydroxide for recycling, the whole process is complicated and the operation process is not easy to control; at the same time, there are many types of chemicals that need to be added, which increases the cost of chemicals and equipment input costs

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