Method for purifying titanium white wastewater

Abstract

The invention relates to a method for purifying titanium white wastewater, which is characterized by comprising the following steps of: adding excess lime milk or carbide slag slurry, performing a neutralization reaction with stirring to obtain precipitate-containing wastewater, wherein the pH value of the wastewater is between 9 and 12; performing solid-liquid separation on the obtained precipitate-containing wastewater, adding sodium carbonate into filter liquor to perform a reaction for 30 to 50 minutes, and adding trisodium phosphate to perform a reaction, and decalcifying; adding sulfuric acid into the decalcified wastewater for reverse neutralization, and regulating the pH value to be between 6 and 9 to obtain purified water. The method has the characteristics of simple flow, no specific requirement on equipment, low consumption of raw materials and the like; and by the method, the treated wastewater can reach the technical standard of national recycling water, so that the wastewater is recycled to production departments, and for a large amount of the generated titanium white wastewater, the method solves the problem of high treatment cost, and has the technical and economic feasibility of industrial application.

Description

technical field [0001] The invention relates to a wastewater treatment method, in particular to a treatment and purification method for sulfuric acid process titanium dioxide wastewater. Background technique [0002] The sulfuric acid titanium dioxide production process is a widely used production method, but it has the problems of large discharge of three wastes such as waste residue, waste water and waste gas, and serious pollution. It needs to discharge a large amount of waste water during the production process, and the discharge of acid waste water alone reaches 100 ~150 tons / ton of titanium dioxide, mainly including washing wastewater generated in the washing step, tail gas washing water generated in the calcination step, tail gas washing water generated in the acidolysis step, equipment and workshop washing water, etc. The impurity components of titanium white acidic wastewater are mainly: iron ions, ferrous ions, metatitanic acid, manganese ions, copper ions, zinc io...

AI Technical Summary

Problems solved by technology

[0004] 1. It is difficult to control the pH value of the treated wastewater within the qualified range, because the neutralization reaction of impurities in the milk of lime and titanium dioxide wastewater is at a mutation point in the pH range of 6-9, and it is required to strictly control the pH value of the second If the amount of lime milk is slightly excessive, the pH value of the mixture will quickly reach more than 10, and it is difficult to use manual or automatic control methods to stably adjust the pH value between 6 and 9;

[0005] 2. The above method is difficult to ensure that the ferrous (iron) ions and other metal ions in the wastewater can be effectively removed and meet the relevant standards;

[0006] Therefore, the wastewater treated by the above method usually only reaches the discharge standard, and has not yet reached the more stringent standard for the reuse of titanium dioxide production, and has not achieved the purpose of recycling titanium dioxide wastewater, and further improvement is needed

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