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(1) Gold mine pollution sources and pollutants 1. Pollution sources In the whole process of gold production, including mining, mineral processing , smelting, equipment transportation, transportation, each process, various components contained in the ore, process flow Adding a variety of pharmaceutical agents, the production site, people's lives constitute an industrial pollution source and a source of domestic pollution.
2. Contaminants For gold mines, the main pollutants can be divided into: water-type pollutants, gas-type pollutants, slag-type pollutants and other (such as: waste water, waste gas, waste residue, etc.). The environmental hazards are: cyanide, arsenic , mercury, flotation reagents, suspended solids, heavy metals, corrosive gases, dust, tailings, waste rock, noise and radioactive materials. The most prominent pollutants in gold mines are mercury and cyanide.
(II) Prevention and treatment principles and technical policies 1. Combination of prevention and control, prevention, and comprehensive management In the process of planning and design, attention should be paid to preventing pollution and damage. The site selection and design of new projects should fully consider the natural environment characteristics and society of the region. Environmental characteristics. Conduct environmental impact assessment in advance, and strive to unify environmental and economic benefits through comprehensive analysis. The location and design of large-scale projects should be based on environmental impact assessment. The design should have “environmental protection articlesâ€. It is necessary to fully consider the requirements for protection, prevention of pollution and damage, and implement “three simultaneous†environmental protection.
Eliminate or reduce pollution during production. Actively experiment with new agents and new processes that use no pollution and reduce pollution. Rationally organize production, strengthen industrial environmental management, achieve closed loops of pollutants as much as possible, reduce pollutant discharge, and improve resource utilization. Actively design and produce new products without pollution or low pollution to prevent pollution caused during processing and transportation.
2. Reasonable use of environmental self-purification ability Combining artificial treatment with natural purification, comprehensive planning, rational layout, and rational use of environmental self-purification ability. According to the characteristics of the region, the natural purification capacity of the atmosphere, water system and soil, determine the economic emission standards and emission methods. Ecological engineering and technical engineering are combined.
3. Combination of decentralized treatment and regional prevention and control Industrial pollution control is mainly based on prevention and control within the plant, but it must be combined with regional prevention and control. Regional pollution prevention and control is mainly based on decentralized prevention and control of each plant.
4. The main ways of combining comprehensive utilization with harmless treatment are: improving resource utilization and reducing pollutant loss; industrial “three wastes†and other waste resources, making full use of combustible gas and waste heat discharged from industrial production. Secondary energy.
5. Adapting to local conditions, combining environmental and economic benefits (III) Main treatment methods for gold mines In the production process of gold mines in China, the pollutants with outstanding hazards include cyanide, mercury, arsenic, flotation reagents, heavy metal ions, waste gas, waste residue, etc. The main governance measures are:
1. Treatment of cyanide-containing wastewater In China, the cyanide-based gold extraction process must be treated for cyanide-containing pollution. The commonly used methods are: alkali chloride method, acid chloride method, Inco SO 2 ˉ air method, acidification-volatilization- Neutralization recovery method, recycling back to use method, tailings natural degradation method, etc. Many cyanide plants in China's gold mines use the lean liquid return cycle method, and the general cycle rate is 50% to 60%. For the absence of tailings ponds, it can be degraded by natural purification such as sunlight, air, and microorganisms.
2. Mercury pollution control Mercury pollution includes pollution of mercury-containing wastewater and mercury vapor. Our current gold mines using amalgamation coarse gold recovery is common, mercury-containing wastewater treatment method relating to the lot, boron, sodium reduction, metal reduction, sulfide precipitation, adsorption and ion exchange method. In the production of gold mines, mercury vapor is a serious pollution. Mainly due to the amalgamation operation. Its concentration can reach 0.9mg/m 3 , generally 0.1mg/m 3 , which has exceeded the workshop hygiene standard (0.01mg/m 3 ) 10 times. Therefore, purification and protective measures such as condensation-adsorption method, permanganic acid must be taken. Potassium adsorption and other methods. According to the survey, gold mines using amalgamation operations (such as Erdaogou Gold Mine) have not experienced mercury poisoning in recent years due to enhanced operational management and protective measures and the use of operator rotation.
3. Treatment of arsenic pollution The arsenic-containing wastewater comes from industrially emitted trivalent arsenite, arsenate, arsenic dust and arsenic oxides. Containing wastewater treatment method are more commonly used are: lime method, Fe, Mn method, a curing method, and a method of soft manganese comprehensive recovery method.
Hunan, China is one of the main mining areas for the production of arsenic-bearing minerals. The Golden Cave Gold Mine uses rotary kiln roasting to remove arsenic and recover white peony (AsO 2 O 3 ), but due to inadequate equipment, management and operation, flue gas, The smoke and dust leakage are relatively serious, so it is necessary to continue to renovate and improve.
In addition to the above-mentioned method for removing arsenic from a large number of arsenic-containing gold mines that need to be developed and utilized, it is necessary to actively explore and study some new technologies for wet arsenic removal, and introduce new methods that have achieved good results abroad, and how to use Xinnuo process.
Golden environmental protection
With the development of gold business, science and technology advances, the gold production process of continuous improvement, the use of large-scale mechanized production methods, use a lot of chemicals to extract gold ore, such as mercury, cyanide and flotation reagents. Therefore, waste water, waste gas and waste residue will seriously pollute the environment, destroy the ecological balance and endanger people's health. Environmental protection and gold production have the same important status, and the state attaches great importance to it. For this reason, prevention and development principles and technical policies have been formulated to strengthen environmental protection.