Process for recovering sulfuric acid and sulfate from waste acid generated in preparation of titanium dioxide by using sulfuric acid method

A sulfate and titanium dioxide technology, applied in the direction of iron sulfate, sulfur trioxide/sulfuric acid, sulfur compounds, etc., to achieve the effect of overcoming equipment corrosion and crystallization blockage, simple equipment, and convenient operation

Inactive Publication Date: 2012-07-04
CHONGQING UNIV
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  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a kind of process of reclaiming sulfuric acid and sulfate from the waste acid of titanium dioxide prepared by sulfuric acid method for the deficiencies of the existing method for reclaiming titanium dioxide waste acid, which can well recycle titanium dioxide waste acid Sulfuric acid recovery, so that the metal sulfate in titanium white waste acid is separated and recycled, effectively solving the problem of scale and blockage of equipment and pipelines caused by the crystallization of metal salts in the process of concentration of waste acid, prolonging the life of the equipment It has the characteristics of high acid recovery rate, high acid concentration, simple process, mature technology, conventional equipment, no pollution, and avoids environmental pollution.

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  • Process for recovering sulfuric acid and sulfate from waste acid generated in preparation of titanium dioxide by using sulfuric acid method
  • Process for recovering sulfuric acid and sulfate from waste acid generated in preparation of titanium dioxide by using sulfuric acid method

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Effect test

Embodiment 1

[0025] The titanium self-spent acid sampled by a company was analyzed. The composition of the waste acid was: sulfuric acid content 20.01%, ferrous sulfate content 15.72%, water content 62.84%, and a small amount of other impurities. Utilize the method of the invention to process the waste titanium dioxide acid of this company.

[0026] Such as figure 1 Shown, a kind of process of reclaiming sulfuric acid and vitriol from the waste acid that sulfuric acid method prepares titanium dioxide, its concrete steps are as follows:

[0027] 1) Precipitation pretreatment

[0028] The waste acid produced in the first washing process of preparing titanium dioxide by the sulfuric acid method is first sent to the inclined plate settling tank 1 through the pipeline, and the precipitation pretreatment is carried out to separate the coarse-grained sulfate. The coarse-grained sulfate precipitated in the inclined plate settling tank 1 is recovered and reused; the supernatant of the inclined pl...

Embodiment 2

[0036] A kind of specific steps of the process of reclaiming sulfuric acid and sulfate from the waste acid of titanium dioxide prepared by sulfuric acid method, same as implementation case 1, wherein:

[0037] In the 2nd) step, the absolute pressure of flash evaporation in the evaporation chamber 6 of the vacuum crystallizer is 35KPa, and crystallization is carried out at a temperature of 85° C. in the crystallization chamber 5 of the vacuum crystallizer. The first heater 9 is heated with steam at a temperature of 135°C, and the temperature of the circulating fluid reaches 120°C. After sampling and analysis, the concentration of sulfuric acid in the primary concentrated acid is 37.6%, and the amount of ferrous sulfate in the primary concentrated acid is 5.83%.

[0038] In step 3), the second heater 10 is heated with steam at a temperature of 145°C, and the temperature of the circulating acid is heated to 140°C. The absolute pressure of vacuum evaporation in the second-stage v...

Embodiment 3

[0041] A kind of specific steps of the process of reclaiming sulfuric acid and sulfate from the waste acid of titanium dioxide prepared by sulfuric acid method, same as implementation case 1, wherein:

[0042] In the 2nd) step, the absolute pressure of flash evaporation in the evaporation chamber 6 of the vacuum crystallizer is 27.5KPa, and crystallization is carried out at a temperature of 76° C. in the crystallization chamber 5 of the vacuum crystallizer. The first circulating pump 19 sends the first heater 9 to heat with steam at a temperature of 130° C., and the temperature of the circulating fluid reaches 118° C. After sampling and analysis, the concentration of sulfuric acid in the primary concentrated acid is 34.8%, and the amount of ferrous sulfate in the primary concentrated acid is 6.89%.

[0043] In step 3), the second heater 10 is heated with steam at a temperature of 135°C, and the temperature of the circulating acid is heated to 130°C. The absolute pressure of v...

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Abstract

The invention relates to a process for recovering sulfuric acid and sulfate from waste acid generated in the preparation of titanium dioxide by using a sulfuric acid method, belonging to the technical field of waste acid treatment in the industrial production. The invention recovers sulfuric acid and sulfate products from waste acid generated in the production process for preparing the titanium dioxide by using the sulfuric acid method through the sedimentation pretreatment and the simple process including the first segment of flash evaporation-crystallization, concentration and separation, the second segment of vacuum evaporation, concentration and separation and the third segment of vacuum evaporation, concentration and separation. The invention has simple process, convenience of operation, simple equipment, high performance price ratio and high yield, high concentration and less impurities of the product acid, can recycle resources without waste liquid or waste residue emission andcan be favorable to environmental protection and energy saving, and emitted exhaust mainly contains air and less vapor, is non-toxic to the environment and can effectively overcome the difficulties of fouling and clogging of the equipment. The invention can be widely applied to the recovery of waste acid in the industrial production and be particularly suitable for recovering the waste acid generated in the preparation of titanium dioxide by using the sulfuric acid method.

Description

technical field [0001] The invention belongs to the technical field of waste acid treatment in industrial production, and in particular relates to a recovery and utilization process of titanium dioxide waste acid in the production process of titanium dioxide prepared by sulfuric acid method. Background technique [0002] At present, the methods for producing titanium dioxide mainly include the chloride method and the sulfuric acid method. The main disadvantage of the chlorination method is that the requirements for raw materials are relatively harsh. Chlorine gas and titanium tetrachloride are poisonous gases at room temperature. These two gases are easy to react with water, resulting in serious process problems and corrosion problems. The sulfuric acid method has the advantages of sufficient sources of raw materials and low production costs. my country is rich in ilmenite reserves, and most enterprises use the sulfuric acid method to produce titanium dioxide. However, a l...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B17/90C01B17/88C01G49/14
Inventor 谭世语张红晶魏顺安董立春吕利平王攀陈红梅罗自萍
Owner CHONGQING UNIV
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