Method for selectively recovering heavy metals from electroplating sludge

A technology for electroplating sludge and heavy metals, applied in the direction of improving process efficiency, etc., can solve the problems of low chromium ion recovery rate, human health and environmental hazards, and large power consumption, and achieve the effect of increasing the precipitation rate of other ions

Inactive Publication Date: 2020-11-20
NANCHANG HANGKONG UNIVERSITY
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Problems solved by technology

Although the total amount of electroplating sludge is not as large as that of wastewater, electroplating sludge is a typical solid waste, mainly formed by chemical precipitation after treatment. The heavy metals contained in it are difficult to degrade. Disposal will become a potential source of environmental pollution, which is very harmful to human health and the environment.
[0003] At present, the methods for extracting heavy metals from electroplating sludge mainly include chemical method, biological treatment method, membrane separation method, solvent extraction method, electrolysis method, electrodeposition method, adsorption method, ion exchange resin method, etc., but these methods are also excellent. Disadvantages coexist, such as many factors affecting the chemical method, electrodialysis, electrodeposition, and electrolysis consume a lot of electricity when treating sludge, the cost of the ion-exchange membrane method is high, the process of the ion-exchange resin method is complicated, and the selected resin Limited capacity and capacity
[0004] Chinese patent "A method for separating iron, chromium, nickel, copper, and zinc from leaching solution of high-iron and high-chromium electroplating sludge" (CN201710150999.1) through replacement reaction, reduction treatment, nitrate chromium precipitation, zinc extraction, and concentrated crystallization to achieve heavy metal separation, but the technological process is complicated, and the purity of ferrous sulfate heptahydrate prepared is not high
Chinese patent "A Method for Selectively Recovering Copper and Nickel from Electroplating Sludge" (CN201010108054.1), the solution after acid leaching is subjected to swirling electrowinning to prepare cathode copper, and the electrowinning solution is adjusted to remove chromium, and then Electrodeposited nickel is prepared by swirl electrowinning to realize the recovery of nickel and copper, but other impurity ions in the electroplating sludge will interfere with the electrowinning process
Chinese patent "a method for selective recovery of heavy metals in electroplating sludge by chlorination and roasting" (CN201811442392.1) mixes chlorination agent with electroplating sludge, roasts and dissolves with water to obtain a solution containing heavy metal ions, but does not Separation of metal ions and poor recovery of chromium ions

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  • Method for selectively recovering heavy metals from electroplating sludge

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Effect test

Embodiment 1

[0030] Such as figure 1 As shown, a method for selective recovery of heavy metals from electroplating sludge is as follows: (1) get 10g electroplating sludge, 12g ammonium chloride, 10ml deionized water (mixing ratio is 1:1.2:1), mix After wet grinding with a ball mill for 24 hours, take it out, dry it in an oven with the drying temperature set at 70°C, and take it out after 6 hours. (2) Suction filter after adding water to dissolve, wash with deionized water 3 times. (3) Add 5.4ml of hydrogen peroxide (6% of the volume of the solution in step 2). (4) prepare nickel, copper, iron standard solution, get the solution dilution certain multiple that gets suction filtration, use atomic absorption spectrometer to measure absorbance and draw concentration, according to formula R (i)=C i ×V / m×x i Calculate the extraction rate. (5) Repeat steps (1), (2), and (3) to take (3) filtrate and place it on a magnetic stirrer at a speed of 150r / min, place the probe of the ultrasonic breaker...

Embodiment 2

[0032] Such as figure 1 As shown, a method for selective recovery of heavy metals from electroplating sludge is as follows: (1) take 8g electroplating sludge, 12g ammonium chloride, 8ml deionized water (mixing ratio is 1:1.5:1), mix Finally, it was wet-milled with a ball mill for 27 hours, then taken out, and dried in an oven at a temperature of 80°C. The product was removed after 8h. (2) Suction filter after adding water to dissolve, wash with deionized water 3 times. (3) add 8.2ml hydrogen peroxide (10% of the solution volume for step 2) Concentration, according to the formula R(i)=C i ×V / m×x i Calculate the extraction rate. (5) Repeat steps (1), (2), (3) to take (3) filtrate and place it on a magnetic stirrer at a speed of 150r / min, place the probe of the ultrasonic breaker in the solution, adjust the power to 100W, and continuously Add solid sodium carbonate to adjust the pH to 3.40, let it stand for 10 minutes, and filter with suction to get iron hydroxide precipita...

Embodiment 3

[0034] Such as figure 1As shown, a method for selective recovery of heavy metals from electroplating sludge is as follows: (1) get 20g electroplating sludge, 26g ammonium chloride, 20ml deionized water (mixing ratio is 1:1.3:1), mix After wet grinding with a ball mill for 36 hours, take it out and dry it in an oven with the drying temperature set at 90°C. The product was removed after 9 h. (2) Suction filter after adding water to dissolve, wash with deionized water 3 times. (3) Add 15 ml of hydrogen peroxide (8% of the volume of the solution in step 2). (4) prepare nickel, copper, iron standard solution, get the solution dilution certain multiple that gets suction filtration, use atomic absorption spectrometer to measure absorbance and draw concentration, according to formula R (i)=C i ×V / m×x i Calculate the extraction rate. (5) Repeat steps (1), (2), and (3) to take (3) and place the filtrate on a magnetic stirrer at a speed of 150r / min, place the probe of the ultrasonic...

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Abstract

The invention discloses a method for selectively recovering heavy metals from electroplating sludge. The method particularly comprises the steps that: step (1), the electroplating sludge, ammonium chloride and water are mixed in proportions, then wet milled with a ball mill and then taken out for drying; step (2), a product obtained in step (1) is dissolved in water, filtered with suction, and washed with deionized water; step (3), a certain amount of 30% hydrogen peroxide is added to a solution obtained in step (2), the concentration of each heavy metal element is determined after standing for a period of time, and the extraction rate is calculated; step (4), a solution in step (3) is taken and adjusted by ultrasonic under 80W-120W conditions and is added a precipitation agent to adjust the pH, so that the heavy metals in the electroplating sludge are precipitated step by step in the form of hydroxides. The method efficiently extracts the heavy metal elements in the electroplating sludge through wet ball milling, and uses the ultrasonic-assisted-step precipitation method to recover several heavy metal elements in the form of precipitation.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, in particular to a method for selectively recovering heavy metals from electroplating sludge. Background technique [0002] China is a big electroplating country. In 2017, there were about 20,000 electroplating enterprises (including electroplating workshops) above designated size in my country, with an annual output value of about 150 billion yuan and an annual output of electroplating processing of about 1.2 billion square meters. In 2018, the product processing area of ​​the electroplating industry was about 1.32 billion square meters. The electroplating industry plays an important role in the operation and development of the national economy and the entire industrial system, and promotes the rapid development of science and technology in our country. However, my country's electroplating industry discharges about 400 million tons of heavy metal wastewater every year, 5×10 4 t o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B23/00C22B15/00
CPCC22B7/006C22B15/0089C22B23/0461Y02P10/20
Inventor 李英朋王忠兵曾桂生刘春力刘畅罗秀玉周磊张捷菲姬海燕关乾
Owner NANCHANG HANGKONG UNIVERSITY
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