Co-treatment method for 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: 2021-08-20
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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  • Co-treatment method for chromium slag and acidic arsenic-containing wastewater
  • Co-treatment method for chromium slag and acidic arsenic-containing wastewater
  • Co-treatment method for chromium slag and acidic arsenic-containing wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] No. I chromium slag (taken from a chromium salt factory in Changsha, Hunan) and No. I arsenic-containing wastewater (taken from a sulfuric acid plant in Daye, Hubei) were co-treated. The components of the treated objects are shown in Table 1 and Table 2. The XRD spectrum 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 (masonite, periclase, wollastonite) and environmental impact during the storage process. Minerals formed by weathering (brucite, calcite, hydrocalumite, hydrotalcite, ettringite), among which metal oxides such as chromite and layered minerals such as hydrocalumite, hydrotalcite, and ettringite have potential arsenic adsorption capacity.

[0063] Weigh 10g of chromium slag sample, add 150mL of waste water sample according to the solid-to-liquid ratio of 0.67:10, stir for 24 hours to obtain the first suspension, and the pH of its su...

Embodiment 2

[0070] In order to compare the difference in chemical dosage and cost between co-treatment and separate treatment, No. I chromium slag and No. I arsenic-containing wastewater were treated separately. The required sulfuric acid consumption of processing No. I chromium slag alone is 750g / kg, and the required ferrous sulfate heptahydrate consumption is 380g / kg, and the Cr(VI) leaching concentration of chromium residue after processing is less than 0.1mg / L, reaches " chromium residue pollution Governance Environmental Protection Technical Specifications (HJ / T 301-2007) "requirements. To treat No. I arsenic-containing wastewater separately, the required lime consumption is 60kg / m 3 , the required ferrous sulfate heptahydrate is 36kg / m 3 , the pH of the treated wastewater is 8.5, and the concentration of As is 0.3mg / L, meeting the requirements of the "Integrated Wastewater Discharge Standard (GB8978-1996)". And as described in embodiment 1, No. I chromium slag and No. I arsenic-co...

Embodiment 3

[0072] The No. II chromium slag sample (taken from a chromium salt factory in Jinan, Shandong) and the No. II arsenic-containing wastewater sample (taken from a sulfuric acid plant in Daye, Hubei) were co-treated. The components of the treated objects are shown in Table 3 and Table 4. Weigh 10g of chromium slag sample, add 1200mL of waste water sample according to the solid-to-liquid ratio of 0.083:10, stir for 24 hours to obtain the first suspension, and the pH of the supernatant is 6.8; then press 3.1kg / m 3 Add ferrous chloride tetrahydrate, stir and react for 24 hours to obtain the second suspension; then press 0.6kg / m 3 Add milk of lime and react with oxygen for 12 hours to obtain the third suspension, the pH of the supernatant is 7.5. The third suspension is filtered to separate the solid and liquid phases to obtain treated chromium residue and waste water. The leaching toxicity test results of the treated chromium slag show that the leaching concentration of Cr(VI) is 0...

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Abstract

The invention belongs to the technical field of harmless treatment of chromium slag and arsenic-containing wastewater, and relates to a co-treatment method of chromium slag and acidic arsenic-containing wastewater. According to the co-treatment method for the chromium slag and the acidic arsenic-containing wastewater, the inherent characteristics and complementarity of the chromium slag and the acidic arsenic-containing wastewater are fully utilized, and neutralization of alkali in the chromium slag, reduction/stabilization of hexavalent chromium, neutralization of acid in the acidic arsenic-containing wastewater and removal of arsenic are synchronously realized; the treatment cost of the chromium slag and the acidic arsenic-containing wastewater is reduced through the thought of treating waste with waste. A large number of strong acid substances exist in the acidic arsenic-containing wastewater, mineral occurrence state Cr (VI) in the chromium slag can be effectively converted into water-soluble state Cr (VI), and mass transfer limitation in the reduction and stabilization process of the Cr (VI) is reduced; and meanwhile, a large amount of mineral components with arsenic adsorption capacity exist in the chromium slag, so that arsenic in the wastewater can be effectively fixed, and the use and treatment cost of chemicals is greatly reduced.

Description

technical field [0001] 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. Background technique [0002] Chromium slag is a highly alkaline industrial waste residue containing hexavalent chromium (Cr(VI)) produced during the production of chromium salts using chromite ore as raw material. Because hexavalent chromium is highly toxic and oxidatively corrosive, and is an internationally recognized carcinogen, chromium slag has been 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 a beautiful China. Wet detoxification is an effective method ...

Claims

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Application Information

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Patent Type & Authority Applications(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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