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Building material and method for preparing calcium sulfate hemihydrates from titanium white waste sulfuric acid

A technology of calcium sulfate hemihydrate and building materials, which is applied in the field of building materials and the preparation of calcium sulfate hemihydrate by using titanium dioxide waste sulfuric acid, can solve the problems of waste of sulfuric acid resources, high processing cost, complicated process, etc., and achieves environmental protection and operability. Strong and economical effect

Inactive Publication Date: 2011-10-12
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is: a large amount of solid waste is produced, mainly containing calcium sulfate, ferric hydroxide and various slag particles, and it causes waste of sulfuric acid resources
The main disadvantages of this method are: complicated process, high energy consumption and high processing cost
Therefore, few titanium dioxide enterprises have successfully applied concentrated treatment to recover waste sulfuric acid

Method used

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  • Building material and method for preparing calcium sulfate hemihydrates from titanium white waste sulfuric acid
  • Building material and method for preparing calcium sulfate hemihydrates from titanium white waste sulfuric acid
  • Building material and method for preparing calcium sulfate hemihydrates from titanium white waste sulfuric acid

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Experimental program
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Effect test

Embodiment 1

[0037] Such as figure 2 As shown, the jacketed reaction tank used is provided with a circulating water inlet and outlet b on the upper and lower parts of the outer wall of the tank a, one end of the stirring shaft c is connected to the external motor of the tank, and the other end extends into the tank , a stirring blade d is installed on the stirring shaft c in the tank body, four baffles e are fixedly installed on the inner wall of the tank body, and a dripping nozzle f, a thermometer socket g, and a pH meter socket h are opened on the upper part of the tank body .

[0038] Process flow of the present invention such as figure 1 As shown, the specific process includes the following steps:

[0039] 1) Add limestone or slaked lime to titanium white waste acid (sulfuric acid with a concentration of 2-10%), stir to let it completely react with sulfuric acid to form calcium sulfate precipitate, and control the pH value to 0.5 to convert the main impurities such as Fe into fine ...

Embodiment 2

[0044] The jacketed reaction tank used in Example 1 was utilized.

[0045] 1) Add limestone or slaked lime to titanium white waste acid (sulfuric acid with a concentration of 2-10%), stir to let it completely react with sulfuric acid to form calcium sulfate precipitate, and control the pH value to 4.5 to convert Fe and other main impurities into fine particles hydroxide precipitation;

[0046] 2) The slurry obtained in step 1) is subjected to solid-liquid separation, the solid phase calcium sulfate dihydrate will be further processed to prepare calcium sulfate hemihydrate, a small amount of lime is added to the liquid phase and natural sedimentation is harmless, and a small amount of solid impurities are piled up to realize calcium sulfate cleaning;

[0047] 3) Add calcium sulfate dihydrate obtained in step 2) into a jacketed reactor, feed circulating water into the jacket of the jacketed reactor, adjust the temperature to 70°C, and add calcium chloride solution , make the mol...

Embodiment 3

[0050] The jacketed reaction tank used in Example 1 was utilized.

[0051] 1) Add limestone or slaked lime to titanium white waste acid (sulfuric acid with a concentration of 2-10%), stir to let it completely react with sulfuric acid to form calcium sulfate precipitate, and control the pH value to 3.0 to convert Fe and other main impurities into fine particles hydroxide precipitation;

[0052] 2) The slurry obtained in step 1) is subjected to solid-liquid separation, the solid phase calcium sulfate dihydrate will be further processed to prepare calcium sulfate hemihydrate, a small amount of lime is added to the liquid phase and natural sedimentation is harmless, and a small amount of solid impurities are stacked to realize calcium sulfate cleaning;

[0053] 3) Add calcium sulfate dihydrate obtained in step 2) into a jacketed reactor, feed circulating water into the jacket of the jacketed reactor, adjust the temperature to 50°C, and add calcium chloride solution , make the mo...

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Abstract

The invention relates to the field of inorganic chemical industry, and particularly relates to a building material and a method for preparing calcium sulfate hemihydrates from titanium white waste sulfuric acid. The method comprises the following steps of: 1) adding limestone or slaked lime into the titanium white waste sulfuric acid, adjusting the pH and reacting to generate precipitates of calcium sulfate in slurry; 2) performing solid-liquid separation to obtain solid of calcium sulphate dehydrate and filtrate; 3) adding calcium chloride solution into the solid of calcium sulphate dehydrate obtained in the step 2), wherein the molar ratio of the calcium chloride to the calcium sulphate dehydrate is 1:(1-2.5), adjusting the concentration of H<+>, stirring and reacting at the temperature of between 30 and 90 DEG C to separate calcium sulphate dehydrate crystal out; and 4) ageing the calcium sulphate dehydrate which is obtained in the step 3), and performing solid-liquid separation to obtain calcium sulphate dehydrate and the calcium chloride solution. The method is used for producing the calcium sulphate dehydrate for building, has good economic benefit and is environment-friendly; and the provided method has high operability and industrialization is easy to realize by the method.

Description

technical field [0001] The invention relates to the field of inorganic chemical industry, in particular, the invention relates to a building material and a method for preparing calcium sulfate hemihydrate by utilizing titanium white waste sulfuric acid. Background technique [0002] In 2010, my country's titanium dioxide output reached 1.47 million tons, and most domestic titanium dioxide factories use sulfuric acid process. In the process of producing titanium dioxide by this method, 20 to 30 tons of waste sulfuric acid of 2% to 10% must be discharged for every 1 ton of titanium dioxide produced. According to rough calculations, the national titanium dioxide enterprises produce at least 20 million tons of waste acid every year. The biggest development problem facing the production of titanium dioxide by the sulfuric acid method is that a large amount of waste acid produced in the production process cannot be comprehensively and efficiently utilized, thereby causing pollutio...

Claims

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Application Information

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IPC IPC(8): C01F11/46C04B11/26
Inventor 李志宝孙顺平
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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