Method for detoxifying and curing Cr(VI) by utilizing metakaolin-based geopolymer added with FeSO4.7H2O

A mineral polymer, feso4·7h2o technology, used in the protection device against harmful chemicals, etc., can solve the problem of difficult to inhibit acid-soluble Cr leaching and other problems, achieve good durability, no secondary pollution, good impermeability Effect

Active Publication Date: 2012-05-30
中部知光技术转移有限公司
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the materials involved in the solidification method in the prior art are mainly cement and mineral polymers, and the limitations of cement itself make it difficult to inhibit the leaching of acid-soluble Cr(VI)
However, there is no effective method for curing Cr(VI) with mineral polymers.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] One way to use FeSO 4 ·7H 2 The method of O-based metakaolin-based mineral polymer detoxification and solidification of Cr(VI) includes the following steps:

[0023] 1) Add 5g of solid NaOH to 25g of water glass solution to prepare an alkaline activator solution; then add 30g of metakaolin to the above alkaline activator solution in portions, stir evenly to obtain a mixed solution;

[0024] 2) Add 0.042g K in turn 2 Cr 2 O 7 And 0.6g FeSO 4 ·7H 2 O to the mixed solution obtained in step 1) and mix evenly;

[0025] 3) Pour the solution obtained in step 2) into a 20×20×20mm mold, after curing at 60°C, demold, seal with a polyethylene film, and cure at 60°C for 1 hour to obtain a mineral polymer with fixed Cr.

[0026] The leaching concentration of total chromium is determined according to the US EPA-TCLP method. The specific method is: pulverize the above-obtained Cr-immobilized mineral polymer to below 9mm, the leaching liquid is an acetic acid solution with a pH of 2.88, and the...

Embodiment 2

[0033] One way to use FeSO 4 ·7H 2 The method of O-based metakaolin-based mineral polymer detoxification and solidification of Cr(VI) includes the following steps:

[0034] 1) Add 5g of solid NaOH to 25g of water glass solution to prepare an alkaline activator solution; then add 30g of metakaolin to the above alkaline activator solution in portions, stir evenly to obtain a mixed solution;

[0035] 2) Add 0.0848g K in turn 2 Cr 2 O 7 And 0.6g FeSO 4 ·7H 2 O to step 1) in the mixed solution obtained and mixed evenly;

[0036] 3) Pour the solution obtained in step 2) into a 20×20×20mm mold, after curing at 60°C, demold, seal with a polyethylene film, and cure at 60°C for 1 hour to obtain a mineral polymer with fixed Cr.

[0037] The leaching concentration of the total chromium obtained in Example 2 is 0.17 mg / L, and the curing rate of chromium is 99.30%, which meets the requirements of the US EPA-TCLP method for Cr (VI) treatment.

Embodiment 3

[0039] One way to use FeSO 4 ·7H 2 The method of O-based metakaolin-based mineral polymer detoxification and solidification of Cr(VI) includes the following steps:

[0040] 1) Add 5g of solid NaOH to 25g of water glass solution to prepare an alkaline activator solution; then add 30g of metakaolin to the above alkaline activator solution in portions, stir evenly to obtain a mixed solution;

[0041] 2) Add 0.170g K in turn 2 Cr 2 O 7 And 1.2g FeSO 4 ·7H 2 O to step 1) in the mixed solution obtained and mixed evenly;

[0042] 3) Pour the solution obtained in step 2) into a 20×20×20mm mold, after curing at 60°C, demold, seal with a polyethylene film, and cure at 60°C for 1 hour to obtain a mineral polymer with fixed Cr.

[0043] The leaching concentration of total chromium obtained in Example 3 is 0.515 mg / L, and the curing rate of chromium is 99%, which meets the requirements of the US EPA-TCLP method for Cr(VI) treatment.

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PUM

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Abstract

The invention provides a method for detoxifying and curing Cr(VI) by utilizing metakaolin-based geopolymer added with FeSO4.7H2O, which comprises the following steps of: 1) adding metakaolin into a solution of an alkali activator in batches, and uniformly stirring to obtain a mixed solution; 2) adding Cr(VI) and FeSO4.7H2O into the mixed solution which is obtained in the step 1) in turn and uniformly mixing, wherein the addition of the Cr(VI) is less than or equal to 0.8 percent of the mass of the mixed solution which is obtained in the step 1), the addition of the FeSO4.7H2O is less than or equal to 16 percent of the mass of the mixed solution which is obtained in the step 1), and the mass ratio of the FeSO4.7H2O to the Cr(VI) is more than or equal to 20; and 3) molding the solution obtained in the step 2), curing, demolding and maintaining in turn to obtain the geopolymer fixed with Cr. The method is environment-friendly, high in chromium curing rate and suitable for controlling acid-soluble Cr.

Description

Technical field [0001] The present invention belongs to a Cr(VI) pollution control method, and specifically relates to a method of using FeSO 4 ·7H 2 Method for detoxification of metakaolin-based mineral polymer of O and solidification of Cr(Ⅵ). Background technique [0002] Chromium salt is an important chemical basic raw material. The production of chromium salt adopts a high-temperature roasting-water immersion-multi-stage evaporation crystallization process, the chromium conversion rate is 75%, and the residue is discharged as chromium residue. About 1.7-4.2 tons of highly toxic chromium slag is discharged for every 1 ton of sodium chromate product produced, and about 7 tons of chromium slag is discharged every 1 ton of metallic chromium produced. According to statistics, since the production of chromium salts in the 1950s, more than 20 cities in my country have accumulated 6 million tons of chromium slag and processed less than 2 million tons. The main chemical components ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A62D3/33A62D101/43
Inventor 陈洁渝王焰新王洪权严春杰朱小燕
Owner 中部知光技术转移有限公司
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