A co-treatment method of chromium slag and acidic arsenic-containing wastewater

A technology for co-processing and chromium slag is applied in the field of co-processing of chromium slag and acidic arsenic-containing wastewater, which can solve the problems of consuming a large amount of acid and consuming a large amount of alkaline chemicals, and achieves the promotion of detoxification, reduction of the use of chemicals and treatment costs, and reduction of The effect of mass transfer limitation

Active Publication Date: 2022-04-08
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Aiming at the defects of the prior art, the object of the present invention is to provide a simple and low-cost method for detoxifying chromium slag and discharging arsenic-containing wastewater up to standard, aiming to solve the problem of consuming a large amount of acid, Technical problems such as the need to consume a large amount of alkaline chemicals when treating arsenic-containing wastewater alone

Method used

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  • A co-treatment method of chromium slag and acidic arsenic-containing wastewater
  • A co-treatment method of chromium slag and acidic arsenic-containing wastewater
  • A co-treatment method of chromium slag and acidic arsenic-containing wastewater

Examples

Experimental program
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Effect test

Embodiment 1

[0062] No. 1 chromium slag (taken from a chromium salt factory in Changsha, Hunan) and No. 1 arsenic-containing wastewater (taken from a sulfuric acid plant in Daye, Hubei) were co-treated. The components of the treatment objects are shown in Tables 1 and 2. The XRD pattern of chromium slag is shown in figure 2 As shown, it can be seen that the chromium slag contains unreacted raw ore (chromite), minerals formed during high-temperature roasting (ororite, periclase, tobermorite), and minerals affected by the environment during storage. Minerals formed by weathering (brucite, calcite, hydrocalumite, hydrotalcite, ettringite), of which metal oxides such as chromite and layered minerals such as hydrocalcite, hydrotalcite, and ettringite have potential arsenic adsorption capacity.

[0063] Weigh 10 g of chromium slag sample, add 150 mL of waste water sample at a solid-to-liquid ratio of 0.67:10, and stir for 24 hours to obtain a first suspension, the pH of the supernatant is 6.4;...

Embodiment 2

[0070] In order to compare the difference of chemical dosage and cost between co-treatment and single treatment, the No. 1 chromium slag and No. 1 arsenic-containing wastewater were treated separately. The amount of sulfuric acid required to treat No. 1 chromium slag alone is 750g / kg, and the required amount of ferrous sulfate heptahydrate is 380g / kg. Environmental Protection Technical Specifications (HJ / T 301-2007)”. To treat No. 1 arsenic-containing wastewater alone, the required amount of lime is 60kg / m2 3 , the required ferrous sulfate heptahydrate is 36kg / m 3 , the pH of the treated wastewater is 8.5 and the As concentration is 0.3mg / L, which meets the requirements of the "Integrated Wastewater Discharge Standard (GB8978-1996)". As described in Example 1, the co-treatment of No. 1 chromium slag and No. 1 arsenic-containing wastewater requires only 25 kg / m of ferrous sulfate heptahydrate. 3 , only need lime milk 3kg / m 3 , greatly reducing the amount of sulfuric acid, l...

Embodiment 3

[0072] The No. II chromium slag sample (taken from a chromium salt plant in Jinan, Shandong) and No. II arsenic-containing wastewater (taken from a sulfuric acid plant in Daye, Hubei) were co-treated. The components of the treatment objects are shown in Tables 3 and 4. Weigh 10 g of chromium slag sample, add 1200 mL of waste water sample at a solid-to-liquid ratio of 0.083:10, and stir for 24 hours to obtain the first suspension, and the pH of the supernatant is 6.8; then press 3.1 kg / m 3 Add ferrous chloride tetrahydrate, stir and react to obtain the second suspension after 24 hours; then press 0.6kg / m 3 Lime milk was added, and the third suspension was obtained after 12 hours of oxygen exposure reaction, and the pH of the supernatant was 7.5. The third suspension is filtered to separate the solid-liquid two phases to obtain the treated chromium slag and waste water. The leaching toxicity test results of the treated chromium slag show that the leaching concentration of Cr(VI...

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Abstract

The invention belongs to the technical field of harmless treatment of chromium slag and arsenic-containing wastewater, and more specifically relates to a method for co-processing chromium slag and acidic arsenic-containing wastewater. A method for co-processing chromium slag and acidic arsenic-containing wastewater provided by the present invention fully utilizes the inherent characteristics and complementarity of chromium slag and acidic arsenic-containing wastewater to simultaneously realize the neutralization of alkali in chromium slag and the reduction of hexavalent chromium / Stabilize and neutralize acid in acidic arsenic-containing wastewater and remove arsenic, and reduce the treatment cost of chromium slag and acidic arsenic-containing wastewater through the idea of ​​"treating waste with waste". There are a large amount of strong acid substances in the acidic arsenic-containing wastewater used in the present invention, which can effectively convert the mineral occurrence state Cr(VI) in the chromium slag into water-soluble Cr(VI), and reduce the mass transfer limitation in the process of reducing and stabilizing Cr(VI) ; At the same time, there are a large number of mineral components with arsenic adsorption capacity in the chromium slag used at the same time, which can effectively fix the arsenic in the wastewater, and greatly reduce the use of chemicals and treatment costs.

Description

technical field [0001] The invention belongs to the technical field of harmless treatment of chromium slag and arsenic-containing wastewater, and more particularly relates to a co-treatment method of chromium slag and acidic arsenic-containing wastewater. Background technique [0002] Chromium slag is a highly alkaline industrial waste slag containing hexavalent chromium (Cr(VI)) produced during the production of chromium salts using chromite as raw material. Because hexavalent chromium is highly toxic and oxidatively corrosive, and is an internationally recognized carcinogen, chromium slag is included in the "National List of Hazardous Wastes". my country's chromium salt industry discharges about one million tons of chromium slag every year. The reasonable and safe disposal of chromium slag is directly related to the healthy development of the chromium salt industry and the construction quality of Beautiful China. Wet detoxification is an effective method for the harmless ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A62D3/37A62D3/36A62D3/30C02F1/72C02F1/66C02F1/28C02F101/10
CPCA62D3/37A62D3/36A62D3/30C02F1/72C02F1/281C02F1/66C02F2101/103
Inventor 王鑫王琳玲李鸿博陈静李瑜玥戴子文张虹丽张玉超吴小龙
Owner HUAZHONG UNIV OF SCI & TECH
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