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Method for purifying thiocyanate ions in cyanide-containing wastewater by means of flocculation and sedimentation

A technology for thiocyanate and cyanide wastewater, which is applied in chemical instruments and methods, precipitation treatment, water pollutants, etc., can solve the problems of high treatment cost, increase the dosage of chemicals, limit the application of oxidation process, etc., and achieves simple process and chemical consumption. less effect

Inactive Publication Date: 2019-03-22
BACKFILL ENG LAB SHANDONG GOLD MINING TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] In actual production, in order to ensure the complete oxidation of cyanide, the amount of oxidant added in production is usually 1.5 to 2 times the theoretical amount, resulting in a large consumption of chemicals in this process and high processing costs
In addition, because the stability of thiocyanate is much higher than that of cyanide, if it is oxidized, the dosage of chemicals must be increased, resulting in increased production costs; thus limiting the application of oxidation technology in the treatment of thiocyanate wastewater

Method used

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  • Method for purifying thiocyanate ions in cyanide-containing wastewater by means of flocculation and sedimentation
  • Method for purifying thiocyanate ions in cyanide-containing wastewater by means of flocculation and sedimentation

Examples

Experimental program
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Effect test

Embodiment 1

[0032] Weigh 2L of cyanidation leaching gold-removal lean liquid, the concentration of thiocyanate in the liquid is 4.23g / L, add concentrated sulfuric acid to adjust the pH value of the solution to about 2.5, aeration stripping for 1h, the carrier gas is adsorbed by lye and then regenerated cyanide sodium. After acidification, 1.5 L of the filtrate was collected by liquid filtration, 12 g of solid ferric sulfate was added, and the mixture was stirred for 30 min and filtered. Take 1L of the filtrate and add lime milk to adjust the pH value to about 7.5, add 6g of solid polymerized ferric sulfate, add 300g of waste mineral powder with -400 mesh accounting for more than 80% after full stirring, stir and flocculate and settle until the solution red disappears, and the treatment process is completed after filtration . After treatment, the concentration of thiocyanate in the tail liquor was 0.68g / L, and the theoretical removal rate reached 83.9%.

Embodiment 2

[0034] Weigh 2L of cyanidation leaching gold removal lean liquid, the concentration of thiocyanate in the liquid is 5.81g / L, add concentrated sulfuric acid to adjust the pH value of the solution to about 2.2, aeration and stripping for 1h, the carrier gas is adsorbed by lye and then regenerated cyanide sodium. After acidification, 1.5 L of the filtrate was collected by liquid filtration, 15 g of solid ferric sulfate was added, and the mixture was stirred for 30 min and then filtered. Take 1L of the filtrate and add lime milk to adjust the pH value to about 8.3, add 8g of solid polymerized ferric sulfate, add 400g of -400 mesh waste mineral powder accounting for more than 80% after full stirring, stir and flocculate and settle until the solution red disappears, and the treatment process is completed after filtration . After treatment, the concentration of thiocyanate in the tail liquor was 0.77g / L, and the theoretical removal rate reached 86.7%.

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Abstract

The invention relates to a method for purifying thiocyanate ions in cyanide-containing wastewater by means of flocculation and sedimentation. By means of research on a purification process of the cyanide-containing wastewater with different concentrations, the process parameters such as solution pH values and the consumption of ferric sulfate and polyferric sulfate are determined; the cyanide-containing wastewater is acidified, and cyanide is recovered; then, the residual cyanide is filtered and removed by means of by precipitation of the ferric sulfate; lime milk is added into the filtrate for adjusting the pH, and the thiocyanate ions are removed by means of flocculation and precipitation of the polyferric sulfate. The method solves the problem that due to the accumulation of the thiocyanate ions in the gold cyanide smelting wastewater, barren liquor can not be reused normally, and the normal smelting process is further influenced; the method guarantees the normal proceeding of goldcyanide leaching and subsequent absorption and replacement processes, and effective improves the smelting recovery rate.

Description

technical field [0001] The invention relates to a method for precipitation and purification of thiocyanate ions in cyanide-containing wastewater, and belongs to the technical field of industrial wastewater treatment. Background technique [0002] At present, gold is mainly extracted directly from gold-bearing minerals by hydrometallurgical processes, and only a small part is obtained from non-ferrous metal by-products of pyrometallurgy. Due to the advantages of low production cost, high recovery rate and strong adaptability to ore, cyanide leaching process is currently the main method of gold production and will still occupy a dominant position for a long time. [0003] Although there are many advantages to extract gold by cyanidation, this process will produce a large amount of gold-removing lean liquid during the production process. Although it can be recycled by returning the lean solution to the leaching process, since most of the gold ore contains sulfide minerals, dur...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F101/18
CPCC02F1/001C02F1/5236C02F1/66C02F9/00C02F2001/007C02F2101/18
Inventor 黄发波
Owner BACKFILL ENG LAB SHANDONG GOLD MINING TECH CO LTD
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