Gold mine wastewater is mainly composed of two parts of wastewater from mining and beneficiation processes. The water quality and volume of dichotoma vary with the nature of soil and rock in the mining area, mining methods, production volume and seasons. The main pollutants in wastewater are suspended matter composed of sand, clay, humus and grass root bark, followed by organic matter. Although this kind of wastewater has a certain degree of stability, it is not easy to settle during the discharge process. Make the natural water turbid and increase the color. At the same time, it has affected and destroyed the phytoplankton group, floating fauna group, bottom sacrificial organism group and photo group in the water ecosystem. The water quality of gold mine wastewater belongs to the multi-stage coarse dispersion system. The dispersion material is silt particles of different sizes, and the dispersion medium is water. The formed clay water inert limb group is composed of limb ridge adsorption layer and diffuse layer. Because a large number of anions are adsorbed on the surface of every ten colloidal edges, the same-same charges between micelles repel each other and it is difficult to precipitate. The composition of different wastewater is different, all wastewater is weakly alkaline, the conductivity of various water is relatively high, and the difference between water quality is relatively small. The ions in various waters are mainly calcium, magnesium cations, sulfate and bicarbonate anions, and the content of other metal ions is not high. The biggest difference in content is the turbidity and suspended solids content of wastewater.
Gold mine wastewater treatment method and Gold mine wastewater treatment polyacrylamide:
1. Coagulation sedimentation method to treat gold mine wastewater. Coagulants that can be used include lime milk, iron sulfate, aluminum sulfate, polyaluminum sulfate, polyaluminum krypton, etc. This treatment method is mainly based on the ss, COD and other contaminants in the water. The polymer state exists. Has a certain degree of stability. The purpose of adding coagulant to wastewater is mainly to reduce the cooling properties of the cavities and suspended impurities in the wastewater, so that they can quickly aggregate into coarser flocs to quickly separate them from the water. Different types of coagulation should be selected for different gold mine wastewater. The conditions for selection are that the coagulation should have a better compression and diffusion layer for the impurities in the cavity, reduce the destabilization and coagulation effect of the electromotive potential, and also have The flocculation effect of the particle bonding and bridging that desorbed to a certain degree must also be considered for economic applicability.
2. Natural precipitation method. The natural precipitation method is a method commonly used at home and abroad to treat gold mine wastewater. It is mainly based on the fact that the dispersed phase in wastewater is a large number of sediment particles, which has a sedimentation effect. Under certain circumstances, the larger the dispersed phase particles, the higher the sedimentation rate. According to different water quality, the precipitation method can be divided into single pond precipitation method, multiple pond exchange precipitation method and multiple pond series precipitation method. The natural sedimentation method mainly uses natural or slightly modified ponds, depressions, mines, etc. to settle wastewater. This method is only suitable for the treatment of certain wastewater that is easy to settle. And it requires a large water storage volume-to ensure that the wastewater has enough residence time. Make waste water pass the discharge standard.
3. Electrolysis, electrolysis technology has been widely used in the water treatment process, but has not been used in the wastewater treatment of placer gold mines. In this regard. We used the Sifangtai placer gold mine disposal technique to conduct a small test. The principle is that aluminum and iron plates are used as electrodes. AlFe ions can be dissolved in the electrolyte in an ionic state after being energized, and after hydrolysis and other reactions, an inorganic polymer electrolyte can be formed. This type of substance can be used as a coagulant to treat various water containing suspended and colloidal impurities.
4. Zinc sulfate method, zinc sulfate method is to add zinc sulfate to gold mine wastewater to precipitate cyanide in the form of zinc cyanide, and then acidify with sulfuric acid. The cyanide concentration can be reduced to less than 0.1mg/l, and the ferricyanide complex can be removed. However, the chemical cost is relatively high, and it cannot oxidize cyanate and thiocyanate.
5. Ion exchange method, which uses anion exchange resin to adsorb cyanide complex, while leaving free cyanide in solution for recycling. The adsorbed cyanide complex is eluted with an acidic solution containing an oxidant, and the absorbed HCN is recycled and reused. This method has high investment costs and can only be used for clear liquids.
6. The ozone oxidation method uses the ozone generated by air or oxygen in the high-voltage and high-frequency electric corona discharge to oxidize cyanide and thiocyanate, but can not destroy ferrocyanide and ferricyanide.
7. Activated sludge method. The decyanation of gold mine wastewater in this system is divided into two stages: firstly, the cyanide and thiocyanate are removed in the rotating bioreactor; the second stage is the nitrification stage, using common nitrosative bacteria and Nitrobacter converts ammonia (NH3) into nitrite and then into nitrate. This method can almost completely remove thiocyanate and ferricyanide complex.
In the treatment of gold mine wastewater by the coagulation precipitation method, the above method mainly relies on the flocculation principle of Gold mine wastewater treatment polyacrylamide, polyaluminum chloride, aluminum sulfate, polyferric sulfate, lime milk and other chemicals, which can reduce the suspension in the wastewater. The turbidity matter makes the substances dispersed in the wastewater pass through adsorption, bridging, and agglomerate into random colloidal particles, and finally form a precipitate. In the process of polyacrylamide treatment of gold mine wastewater, according to the water quality characteristics of gold mine wastewater, anionic polyacrylamide is mostly selected. When anionic polyacrylamide is used for treatment, they can not only accelerate the sedimentation of pollutants and pulp in wastewater, and provide treatment efficiency, but also can make the treated wastewater clear to facilitate later recycling.