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

A mineral polymer, metakaolin technology, applied in the direction of protection devices against harmful chemicals, etc., can solve the problem of difficulty in inhibiting acid-soluble Cr leaching, etc., and achieve the effects of good durability, simple process flow and large solidification amount.

Active Publication Date: 2012-06-06
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 The metakaolin-based mineral polymer detoxification of O and the method for solidifying Cr, it comprises the steps:

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

[0024] 2) Then add 0.042g K in turn 2 Cr 2 o 7 and 0.6gNa 2 S·9H 2 0 to step 1) in the resulting mixed solution, and mix homogeneously;

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

[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 pulverized to less than 9mm, and the l...

Embodiment 2

[0033] One using the addition of Na 2 S·9H 2 The metakaolin-based mineral polymer detoxification of O and the method for solidifying Cr, it comprises the steps:

[0034] 1) Add 5 g of solid NaOH to 25 g of water glass solution to form an alkaline activator solution; then add 30 g of metakaolin to the above alkaline activator solution in stages, and 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 0 to step 1) in the resulting mixed solution and mix uniformly;

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

[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 treatment requirements of Cr(VI) in the US EPA-TCLP method.

Embodiment 3

[0039] One using the addition of Na 2 S·9H 2 The metakaolin-based mineral polymer detoxification of O and the method for solidifying Cr, it comprises the steps:

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

[0041] 2) Then add 0.170g K in turn 2 Cr 2 o 7 and 1.2g Na 2 S·9H 2 0 to step 1) in the resulting mixed solution and mix uniformly;

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

[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%, which meets the treatment requirement of Cr(VI) in the US EPA-TCLP method.

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PUM

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Abstract

The invention provides a method for detoxifying and solidifying Cr 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), be specifically related to a kind of method utilizing adding Na 2 S·9H 2 O's metakaolin-based mineral polymer for detoxification and solidification of Cr. 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 emitted for every 1 ton of sodium chromate produced, and about 7 tons of chromium slag is emitted 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 chemic...

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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