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Process for recovering chrome yellow from chrome containing sewage

A treatment method and technology for chromium wastewater, applied in water/sewage treatment, adsorption water/sewage treatment, water/sludge/sewage treatment, etc., can solve the problems of high separation cost, secondary water pollution, secondary pollution, etc. , to achieve the effect of high recovery rate, avoiding secondary pollution and low treatment cost

Inactive Publication Date: 2002-10-09
WUHAN CHEM COLLEGE
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Problems solved by technology

In the prior art, there are many methods for recovering chromium from chromium-containing wastewater to produce chrome yellow, but there are often more lead ions in the wastewater treated by these methods, causing secondary pollution to water
At present, the treatment method of reducing agent ferrous sulfate is usually used, which is to convert Cr 6+ reduced to Cr 3+ , and then make Cr under strongly alkaline conditions 3+ Hydroxide precipitation is generated, and this precipitation and the resulting Fe(OH) 3 The precipitates are all colloidal, extremely difficult to filter, and the cost of separation is high. In addition, in acidic media, Cr 3+ It will dissolve again and easily generate Cr 6+ compounds, causing secondary pollution

Method used

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  • Process for recovering chrome yellow from chrome containing sewage
  • Process for recovering chrome yellow from chrome containing sewage

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Embodiment 1: chromium-containing wastewater is prepared by potassium dichromate, the concentration of chromium is 700.0mg / l, pH=4.30, in 1000ml wastewater, adding lead ion concentration is 20.72g / l wastewater 145ml, pH=1.26, in Under the conditions of pH 1.48 and temperature 40°C, stir for 10 minutes, separate the precipitate from water, and obtain 4.298 g of chrome yellow precipitate. The concentration of chromium in the wastewater is 0.68 mg / l, and the concentration of lead is 145.98 mg / l. The recovery rate of chromium is 99.89%, and the recovery rate of lead is 94.44%. In the wastewater from which chrome yellow is separated, add activated carbon fluoroapatite at a ratio of 17.46kg / t, and stir for 2 hours at PH=5.7 and normal temperature. , Filtration, the concentrations of lead and chromium ions in the filtrate are 0.51mg / l and 0.01mg / l respectively, and the waste completely meets the national emission standard of GB8978-1996.

Embodiment 2

[0012] Embodiment 2: chromium electroplating waste water, the concentration of chromium is 37.0mg / l, in 800ml chromium-containing waste water, add lead ion concentration and be 6.5ml of lead-containing solution waste water of 27.72g / l, pH=3.5, stir under the condition of temperature 40 ℃ In 10 minutes, 0.1755g of sediment was obtained, and the content of chrome yellow in the sediment was 88.15%, and the concentration of chromium in the waste water dropped to 2.4mg / l, and the recovery rate of chromium was 93.53%; the concentration of lead was 2.45mg / l, and the recovery of lead The rate is nearly 98.53%; in the wastewater from which chrome yellow was separated, add activated carbon fluoroapatite at a ratio of 6.2kg / t, stir for 2 hours at PH=5.7 and room temperature, and filter, the lead, The concentrations of chromium ions are 0.75mg / l and 0.21mg / l respectively, and the treated wastewater fully meets the discharge standard.

Embodiment 3

[0013] Embodiment 3: chromium-containing waste water is prepared by potassium dichromate, and the concentration of chromium is 100.0mg / l, and PH=5.42, and in 1000ml waste water, adding the waste water 19.5ml that lead ion concentration is 27.72g / l, PH=21.26, Then stir for 10 minutes at pH=2.7 and temperature at 40°C to obtain 0.615g of chrome yellow precipitate, the concentration of chromium in the wastewater is 1.17mg / l, the concentration of lead is 7.19mg / l, and the recovery rate of chromium is 98.81% , the lead recovery rate is 98.19%; in the waste water that separates chrome yellow, by the proportioning of 19.6kg / t, add active carbon fluoroapatite (the active carbon fluoroapatite of 1t waste water 19.6kg), at PH=5.4 , under room temperature conditions, stirred and mixed for 2 hours, filtered, and the concentrations of lead and chromium ions in the filtrate were measured to be 0.81mg / l and 0.01mg / l respectively.

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Abstract

A process for recovering chrome yellow from the Cr-containing waste water and removing metallic ions includes adding the solution containing Pb (2+) ions to said waste water to generate PbCrO4 precipitate and reduce the Cr (6+) concentration to lower than 0.5 mg / L, solid-liquid separation, drying the solid, cooling, pulverizing to obtain chrome yellow powder, adding francolite to the liquid to adsorb Cr (6+) and Pb (2+) ions, solid-liquid separation, and draining the liquid.

Description

technical field [0001] The invention relates to a method for comprehensively treating chromium-containing wastewater, recovering chrome yellow therefrom and removing metal ions in water, belonging to the technical field of environmental protection engineering. Background technique [0002] In the production process of some industries such as pigment production, electroplating, and mechanical processing, different concentrations of Cr-containing 6+ Wastewater, since chromium is a scarce resource in our country and an important raw material in industry, the comprehensive recovery of chromium and other metals in wastewater is not only beneficial to water purification, but also has important economic value. In the prior art, there are many methods for recovering chromium from chromium-containing wastewater to produce chrome yellow, but there are often more lead ions in the wastewater treated by these methods, causing secondary pollution to water. At present, the treatment metho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/14C02F1/28C02F1/62C09C1/34
Inventor 钟康年刘羽罗惠华
Owner WUHAN CHEM COLLEGE
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