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

A mineral polymer, feso4·7h2o technology, applied in the direction of protection against harmful chemicals, etc., can solve the problem of difficult to inhibit acid-soluble Cr leaching, etc., to achieve good durability, high curing rate, no secondary pollution. Effect

Active Publication Date: 2011-09-28
中部知光技术转移有限公司
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  • Summary
  • Abstract
  • Description
  • 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] A method that utilizes the addition of FeSO 4 ·7H 2 O metakaolin-based mineral polymer detoxification and solidification Cr (Ⅵ) method, it comprises the following steps:

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

[0024] 2) Then 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 well;

[0025] 3) The solution obtained in step 2) was poured into a mold of 20×20×20 mm, cured at 60°C, demoulded, sealed with a polyethylene film, and cured at 60°C for 1 hour to obtain a mineral polymer with Cr immobilized.

[0026] According to the U.S. EPA-TCLP method, the leaching concentration of total chromium is measured. The specific method is: the above-mentioned obtained Cr-fixed mineral polymer is crushed to below 9mm, and the leaching solutio...

Embodiment 2

[0033] A method that utilizes the addition of FeSO 4 ·7H 2 O metakaolin-based mineral polymer detoxification and solidification Cr (Ⅵ) method, it comprises the following steps:

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

[0035] 2) Then add 0.0848g K in sequence 2 Cr 2 o 7 and 0.6g FeSO 4 ·7H 2 O to the mixed solution obtained in step 1) and mix well;

[0036] 3) The solution obtained in step 2) was poured into a mold of 20×20×20 mm, cured at 60°C, demoulded, sealed with a polyethylene film, and cured at 60°C for 1 hour to obtain a mineral polymer with Cr immobilized.

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

Embodiment 3

[0039] A method that utilizes the addition of FeSO 4 ·7H 2 O metakaolin-based mineral polymer detoxification and solidification Cr (Ⅵ) method, it comprises the following steps:

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

[0041] 2) Then add 0.170g K in sequence 2 Cr 2 o 7 and 1.2g FeSO 4 ·7H 2 O to the mixed solution obtained in step 1) and mix well;

[0042] 3) The solution obtained in step 2) was poured into a mold of 20×20×20 mm, cured at 60°C, demoulded, sealed with a polyethylene film, and cured at 60°C for 1 hour to obtain a mineral polymer with Cr immobilized.

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

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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 invention belongs to the pollution control method of Cr(Ⅵ), in particular to a method of using FeSO 4 ·7H 2 O. Metakaolin-based mineral polymers for detoxification and solidification of Cr(VI). Background technique [0002] Chromium salt is an important chemical basic raw material. The production of chromium salt adopts high-temperature roasting-water immersion-multi-stage evaporation crystallization process, the conversion rate of chromium is 75%, and the residue is discharged as chromium slag. About 1.7-4.2 tons of highly toxic chromium slag is discharged for every 1 ton of sodium chromate produced, and about 7 tons of chromium slag is discharged for every 1 ton of metal 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 stockpiles, and less than 2 million tons have been disposed of. The main chemical components of ...

Claims

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Application Information

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Patent Type & Authority Applications(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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