Method for extracting NaSCN from thiocyanate-containing wastewater solution

A technology containing thiocyanate and aqueous solution, applied in thiocyanate, chemical instruments and methods, water/sewage multi-stage treatment, etc., can solve the problem of low adsorption efficiency of weakly basic anion exchange resin, high cost of reverse osmosis membrane, Shortened service life and other problems, to achieve the effect of wide industrial application, low cost and low production cost

Inactive Publication Date: 2011-02-09
WUHAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantage of this method is that in addition to thiocyanate, the improved ADA desulfurization waste liquid also contains thiosulfate, sulfate, cyanide and other ions, which reduce the adsorption efficiency of weakly basic anion exchange resins.
Although this method can obtain high-purity sodium thiocyanate, the cost of reverse osmosis membrane is high, and it is easy to cause membrane fouling during operation, resulting in shortened service life

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A method for extracting NaSCN from a thiocyanate-containing wastewater solution. Firstly, the aqueous solution containing thiocyanate is adsorbed by activated carbon and filtered to obtain a primary filtrate; then, under normal pressure and 10°C-20°C, a dissolving agent is added to the primary filtrate, and the amount of the dissolving agent added is one time 1 to 2 times the volume of the filtrate, the adding rate of the eluting agent is 50mL / h~150mL / h, stirring at a stirring speed of 100r / min~200r / min during the addition of the eluting agent; Stand still for 15-20 minutes, and filter with suction to obtain the secondary filtrate; then evaporate and crystallize the secondary filtrate to obtain NaSCN crystal product with a purity of 87.61-91.23%.

[0025] The eluent is a mixed solvent of ethanol and acetone; the volume ratio of ethanol to acetone is (0.25-0.5):1.

Embodiment 2

[0027] A method for extracting NaSCN from a thiocyanate-containing wastewater solution. First, the aqueous solution containing thiocyanate is adsorbed by activated carbon and filtered to obtain a primary filtrate; then, under normal pressure and 15°C to 25°C, a dissolving agent is added to the primary filtrate, and the amount of the dissolving agent added is one time 2 to 3 times the volume of the filtrate, the adding rate of the eluting agent is 150mL / h~250mL / h, and stirring at a stirring speed of 200r / min~300r / min during the addition of the eluting agent; Stand still for 20-30 minutes, filter with suction to obtain the secondary filtrate; then evaporate and crystallize the secondary filtrate to obtain NaSCN crystal product with a purity of 88.82-93.23%.

[0028] The eluent is a mixed solvent of ethanol and acetone; the volume ratio of ethanol to acetone is (0.5-1.5):1.

Embodiment 3

[0030] A method for extracting NaSCN from a thiocyanate-containing wastewater solution. Firstly, the aqueous solution containing thiocyanate is adsorbed by activated carbon and filtered to obtain a primary filtrate; then, under normal pressure and 20°C to 30°C, a dissolving agent is added to the primary filtrate, and the amount of the dissolving agent added is one time 3 to 4.5 times the volume of the filtrate, the addition rate of the dissolution agent is 250mL / h to 350mL / h, and the stirring speed is 300r / min to 400r / min during the addition of the dissolution agent; Stand still for 25-30 minutes, filter with suction to obtain the secondary filtrate; then evaporate and crystallize the secondary filtrate to obtain NaSCN crystal product with a purity of 90.17-94.25%.

[0031] The eluent is a mixed solvent of ethanol and acetone; the volume ratio of ethanol to acetone is (1.5~2):1.

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PUM

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Abstract

The invention specifically relates to a method for extracting NaSCN from thiocyanate-containing wastewater solution. The technical scheme comprises the following steps: adsorbing the thiocyanate-containing wastewater solution by active carbon and filtering to obtain primary filtrate; adding elution agent into the primary filtrate under normal pressure at 10 to 50 DEG C, wherein the volume of the added elution agent is 1 to 8 times of that of the primary volume, and the addition seed of the elution agent is 50 to 600 mL/h; stirring at a speed of 100 to 600 r/min during the addition of the elution agent; after adding the elution agent, standing for 15 to 30 min and filtering to obtain secondary filtrate; and evaporating and crystallizing the secondary filtrate to obtain the NaSCN crystal. The method has the characteristics of low cost, environmental protection and the like, and the purity of extracted NaSCN reaches 87 to 96%.

Description

technical field [0001] The invention belongs to the technical field of extracting sodium thiocyanate inorganic salt. Specifically relates to a method for extracting NaSCN from thiocyanate-containing wastewater solution. technical background [0002] Sodium thiocyanate (NaSCN) is a valuable chemical raw material with a wide range of applications. It is used in the textile industry for acrylonitrile fiber spinning, fabric dyeing and vat dyes; it is used for the separation of antibiotics in the pharmaceutical industry; In the chemical industry, it is used for rubber processing and the manufacture of artificial mustard oil, etc.; in the pesticide industry, it is used for the manufacture of insecticides and herbicides, etc. In addition, sodium thiocyanate is also needed in black nickel plating and color film manufacturing. Therefore, extracting high-purity sodium thiocyanate has high economic value. [0003] The coal material contains 0.5% to 1.2% sulfur in the coking producti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01C3/20C02F9/02
Inventor 王光辉万胜张胜兰邱江华曾丹林田永胜
Owner WUHAN UNIV OF SCI & TECH
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