Treatment method of waste acid in titanium dioxide production process

A technology of production process and treatment method, which is applied in the direction of iron oxide, sulfate/bisulfate preparation, iron oxide/hydroxide, etc., which can solve the problem of high processing cost, large energy consumption, latent heat of phase change evaporation major issues

Pending Publication Date: 2021-09-03
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The method of using quicklime to neutralize waste acid produces a large amount of solid waste, which not only costs a lot of money, but also takes up a lot of land for landfill. In today's increasingly tense land resources, this development model must be changed.
For low-concentration spent acid solutions, the cost of membrane technology and evaporative concentration is relatively high, because the latent heat of phase change evaporation of water is large, and the concentration and evaporation process for a large amount of low-concentration waste acid produced every day requires a large amount of energy consumption. , which is inconsistent with the current environmental protection requirements for energy saving and carbon reduction. Therefore, the energy consumption cost of the evaporation and concentration process is very high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] In the 40 tons of 5% waste sulfuric acid produced in the rinsing process, 1.1 tons of quicklime was added, and the molar ratio of calcium oxide to sulfuric acid was 1:1. The generated calcium sulfate is precipitated and separated, and then 3.1 tons of sodium hydroxide with a mass concentration of 10% is added to the remaining solution, and the pH is about 8 at this time. The resulting precipitate was filtered, washed with tap water, and dried at 120° C. for 40 minutes to obtain 0.6 tons of magnetic ferric oxide particles.

Embodiment 2

[0009] In the 30 tons of 1% waste sulfuric acid produced in the rinsing process, 0.14 tons of quicklime was added, and the molar ratio of calcium oxide to sulfuric acid was 0.8:1. The generated calcium sulfate is precipitated and separated, and then 1.05 tons of potassium hydroxide with a mass concentration of 25% is added to the remaining solution, and the pH is about 7 at this time. The resulting precipitate was filtered, washed with tap water, and dried at 95° C. for 120 minutes to obtain 0.36 tons of magnetic iron ferric oxide particles.

Embodiment 3

[0011] In the 35 tons of 3% waste sulfuric acid produced in the rinsing process, 0.54 tons of quicklime was added, and the molar ratio of calcium oxide to sulfuric acid was 0.9:1. The generated calcium sulfate is precipitated and separated, and then 2.0 tons of sodium hydroxide with a mass concentration of 20% is added to the remaining solution, and the pH is about 7.5 at this time. The resulting precipitate was filtered, washed with tap water, and dried at 105° C. for 90 minutes to obtain 0.77 tons of magnetic ferric oxide particles.

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PUM

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Abstract

The invention relates to the field of waste treatment, in particular to a method for treating waste acid in a titanium dioxide production process. The invention aims to solve the problem that a large amount of solid waste is generated due to the fact that waste acid generated in titanium dioxide production by a sulfuric acid method is neutralized by quicklime. The implementation process of the method comprises the steps of adding quick lime into waste acid according to a certain mass ratio, uniformly mixing to generate calcium sulfate precipitate, and separating the precipitate through a settling pond; and adding a sodium hydroxide or potassium hydroxide solution with a certain concentration into the residual solution according to a certain proportion to obtain iron hydroxide precipitates, filtering the precipitates, centrifugally separating and then drying at a certain temperature to obtain magnetic ferroferric oxide, wherein the residual aqueous solution can be concentrated to prepare sodium sulfate or potassium sulfate and can also be reused in the rinsing process. The method can greatly reduce the solid waste generation amount in titanium dioxide production, can generate remarkable economic benefits, and has a wide application prospect.

Description

Technical field: [0001] The patent of the present invention relates to the field of waste treatment, in particular to a treatment method for waste acid in the production process of titanium dioxide. Background technique: [0002] Titanium dioxide is widely used in various industries, and its processing and production methods are mainly sulfuric acid method and chlorination method. For the production of titanium dioxide by the sulfuric acid method, a large amount of waste acid will be produced. The production of one ton of titanium dioxide will produce 5 to 6 tons of waste sulfuric acid of about 20-30%, and 30-6 tons of waste sulfuric acid of about 1-5% will be produced in the rinsing process. 40 tons. Usually, most manufacturers use quicklime to neutralize waste acid to generate a mixture of calcium sulfate, ferrous hydroxide and ferric hydroxide. As solid waste, these mixtures have little use in other fields, so they can only be landfilled. For the production of titanium...

Claims

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Application Information

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IPC IPC(8): C01G49/08C01D5/06
CPCC01G49/08C01D5/06
Inventor 王胜强
Owner NANKAI UNIV
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