A kind of regeneration method of heavy metal chromium in chrome tanning sludge
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A technology for heavy metals and sludge, applied in sludge treatment, chemical instruments and methods, water/sludge/sewage treatment, etc. Inexpensive effect
Inactive Publication Date: 2016-10-05
ZHEJIANG GONGSHANG UNIVERSITY
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However, the above method still has the problem of low chromium recycling rate, especially for chromium-rich chrome tanned sludge, how to improve the chromium recycling rate in sludge still needs to be studied and solved
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Embodiment 1
[0044] A method for regenerating heavy metal chromium in chrome tanned sludge, comprising:
[0045] (1) Add chrome tanning sludge to hydrochloric acid with a concentration of 5mol / L, so that the solid-liquid ratio of chrome tanning sludge to hydrochloric acid is 10g / L, and react with stirring at 500rpm for 1.5h at 50°C, and the obtained The mixed solution is filtered through a 0.22 μm filter membrane to obtain a leaching solution, and the above steps are repeated for a second leaching;
[0046] (2) Using sodium bisulfite as a reducing agent, the Cr in the leaching solution 6+ reduced to Cr 3+ , sodium bisulfite and Cr 6+ The mass ratio is 5:1;
[0047] (3) Dilute the Cr containing Cr in step (2) with deionized water 3+ leaching solution, take 30mL containing Cr 3+ Add 0.7g of 732 sodium cation exchange resin to the leach solution with a concentration of 500mg / L for adsorption, and shake at 200rpm for 60min at 30°C;
[0048] (4) get 30mL mass concentration and be 8% hydro...
Embodiment 2
[0052] A method for regenerating heavy metal chromium in chrome tanned sludge, comprising:
[0053] (1) Add the chrome tanned sludge to hydrochloric acid with a concentration of 1mol / L, so that the solid-liquid ratio of the chrome tanned sludge to hydrochloric acid is 5g / L, and react with stirring at 500rpm for 1h at 40°C, and the obtained The mixed solution was filtered through a 0.22 μm filter membrane to obtain the leaching solution;
[0054] (2) Using sodium bisulfite as a reducing agent, the Cr in the leaching solution 6+ reduced to Cr 3+ , sodium bisulfite and Cr 6+ The mass ratio is 4:1;
[0055] (3) Dilute the Cr containing Cr in step (2) with deionized water 3+ leaching solution, take 30mL containing Cr 3+ Add 0.6g of 732 sodium cation exchange resin to the leachate with a concentration of 500mg / L for adsorption, and shake at 200rpm for 60min at 30°C;
[0056] (4) get 30mL mass concentration and be the sulfuric acid of 8% and load Cr in step (3) 3+ The resins w...
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Abstract
The invention discloses a chrome tanning sludge heavy metal chromium regeneration method, and the method includes extraction of chrome tanning sludge with hydrochloric acid, reduction of Cr<6 +> in the leaching solution by use of sodium bisulfate, adsorption of Cr<3 +> by use of 732 sodium type cation exchange resin, and desorption of the Cr<3 +> on the resin by use of hydrochloric acid or sulfuric acid. According to the method, the hydrochloric acid as an acid leaching extraction agent is cheap, and can effectively leach metal chromium in the chrome tanning sludge, the chromium efficiency is more than 80%; the sodium 732 type cation exchange resin as an adsorbent can preferentially adsorb the Cr<3 +> in the leaching solution, the adsorption and recovery rate can reach up to 96.1%, and the efficient chromium separation and purification can be realized. At the same time, the resin can be recycled by regeneration, the processing cost can be effectively reduced; by desorption of the Cr<3 +> by use of hydrochloric acid or sulfuric acid, corresponding chromium chloride solution and chromic sulfate solution products can be obtained, and the chromium chloride solution and chromic sulfate solution products can be can used in trivalent chromium electroplating industry.
Description
technical field [0001] The invention relates to the technical field of environmental protection, in particular to a method for regenerating heavy metal chromium in chrome tanning sludge. Background technique [0002] The tanning process is mainly divided into pre-tanning preparation section, tanning section and wet processing section, among which leather tanning is the main operation step in the tanning process, which has the characteristics of effectively avoiding environmental factors, such as microbial degradation, heat and moisture, etc. The quality of leather has an important impact, and a large amount of trivalent chromium salt, namely basic chromium sulfate, is the most important raw material in the leather tanning process. Chrome tanning sludge is the sludge formed by alkali precipitation of wastewater produced in the leather tanning process, and the absorption rate of chrome tanning agent to raw hides during the tanning process is usually only about 55%, and the res...
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