Method for detoxifying and solidifying Cr(VI) by utilizing metakaolin base mineral polymer added with Na2S.9H2O

A technology of mineral polymer and metakaolin, which is applied in the protection device against harmful chemical agents, etc., can solve the problem of difficulty in inhibiting the leaching of acid-soluble Cr, and achieve the effect of good durability, high curing rate and large curing amount

Active Publication Date: 2011-09-14
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] One using the addition of Na 2 S·9H 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 0.6 gNa 2 S·9H 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 solution is an acetic ...

Embodiment 2

[0033] One using the addition of Na 2 S·9H 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 0.170g K in turn 2 Cr 2 o 7 and 1.05g Na 2 S·9H 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 0.13mg / L, and the solidification rate of chromium is 99.73%, which meets the Cr(VI) treatment requirements of the US EPA-TCLP law.

Embodiment 3

[0039] One using the addition of Na 2 S·9H 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 Na 2 S·9H 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 0.10 mg / L, and the solidification rate of chromium is 99.80%, meeting the Cr(VI) treatment requirements of the US EPA-TCLP law.

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PUM

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Abstract

The invention provides a method for detoxifying and solidifying Cr(VI) by utilizing a metakaolin base mineral polymer added with Na2S.9H2O, comprising the following steps: (1) adding metakaolin into an alkaline exciting agent solution at different times, and stirring evenly to obtain a mixed solution; (2) then successively adding Cr(VI) and Na2S.9H2O into the mixed solution obtained in the step (1), and evenly mixing, wherein the addition of the Cr(VI) is less than or equal to 1.2wt% of the mixed solution obtained in the step (1), the addition of the Na2S.9H2O is less than or equal to 21wt% of the mixed solution obtained in the step (1), and the mass ratio of the Na2S.9H2O to the Cr(VI) is more than or equal to 17.5; and (3) successively putting the solution obtained in step (2) into a die, solidifying, demoulding and curing to obtain the mineral polymer fixed with Cr. The method is environmentally-friendly, ensures high chromium solidification rate and is 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 2 S·9H 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 chromium slag are Ca...

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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