Treatment of arsenic-containing polluted acid with no or less slag production
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The treatment of arsenic-containing polluted acid is generally carried out by the lime iron salt method, which has good results. But the disadvantage is that the amount of slag is large and the management cost of the slag yard is high. I would like to ask you if there is any way to prevent or reduce slag. It would be better if arsenic could be extracted in the form of white arsenic. The specific data are as follows:: 5~10g/L Si: 1~5g/LFe: 1~5g/L This post was last edited by Welcome on 2009-2-11 16:46 ]
In order to reduce the amount of slag discharge, it is enough to use waste alkali instead of lime and add calcium ions for treatment.
I disagree with the second floor in my opinion. If waste alkali is used as a neutralizing agent, although no waste residue will be produced, the water will contain a large amount of sodium sulfate and sodium sulfite, and the discharge is not allowed. In addition, the cost is definitely higher than the lime method.
Arsenic can be removed in the form of arsenic pentasulfide precipitation using agents containing sulfur ions.
In order to reduce the amount of slag discharge, it is enough to use waste alkali instead of lime and add calcium ions for treatment.
The solution of neutralizing with waste alkali and adding calcium ions is used for pretreatment. If the discharge water contains sulfate ions or sulfite ions, it is easier to handle. The subsequent process is anaerobic, and the sulfate and sulfite are reduced to sulfide ions, which react with iron ions in the water to form a precipitate, which can be properly treated through liquid return separation. There are no strict regulations and requirements for the conductivity of wastewater discharge.
A new process for recycling arsenic-containing wastewater. Shandong Tiancheng Bio-Gold Co., Ltd. (formerly Laizhou Gold Smelting Plant), after successfully introducing a foreign advanced bacterial oxidation pretreatment arsenic-containing gold concentrate project, has carried out technical transformation of the post-treatment process of the introduced arsenic-containing wastewater, realizing the complete recycling of arsenic-containing wastewater in the oxidation system after neutralization. On June 17, 2003, the project successfully passed the environmental protection engineering acceptance. The company was founded in 1987. In the early stage of production, due to the lack of supporting cyanide wastewater treatment facilities, the environmental pollution problem remained unresolved for a long time. After that, the company invested 1.35 million yuan in technological transformation and finally achieved * * stipulated emission standards. However, meeting the discharge standards does not mean that there is no pollution. Therefore, the research topic of "zero discharge of cyanide-containing wastewater" is proposed to completely eradicate the pollution hazards. The company invested 700,000 yuan in venture capital and cooperated with Tsinghua University to tackle key problems. After more than two years of hard work, in 1997, it successfully developed a "new process for solvent extraction to treat cyanide-leached gold lean liquid" and became the first gold company in the country to achieve zero discharge of cyanide-containing wastewater. This process is * * The State Environmental Protection Administration confirmed that“ * * Key Environmental Protection Practical Technology (Category A) Project”. In recent years, in view of the large resource reserves of refractory arsenic-containing gold concentrate and the lack of successful domestic process technology, the company took environmental protection as the theme and fully investigated and demonstrated known arsenic-containing refractory treatment options at home and abroad, and resolutely abandoned the process technology that caused serious pollution to the environment. In March 2003, the internationally advanced biological gold extraction process and technology was introduced from South Africa and Australia to build a refractory arsenic-containing gold concentrate project. At the same time, it also introduced a post-treatment process for arsenic-containing wastewater, and successfully tested it in May 2003. The total arsenic content in the water after neutralization of the arsenic-containing wastewater was less than 0.5×10-6. * * Industrial emission standards. Since 2002, the arsenic-containing wastewater post-treatment process has been undergoing technical transformation. Process experiments have been conducted, the technical transformation plan has been determined, and a series of work has been carried out such as infrastructure construction, equipment procurement, and process debugging. By mid-April, all arsenic-containing wastewater has been neutralized and recycled in the oxidation system. In this way, based on saving 500m0 of water per day, 150,000m0 of water can be saved throughout the year, with obvious economic and social benefits.