In the sense of comprehensive engineering, the design of the tailings pond is not determined by the nature of the solids, but by the nature of the wastewater. Therefore, the physical properties of tailings cannot be considered alone, and the chemical properties of tailings wastewater must be fully understood so that the risk level of tailings pond engineering can be systematically clarified. Both flotation and leaching may chemically denature the ore. Various organic chemicals, such as fatty acids, oils and polymers are added in the flotation process, because they are generally low in concentration, low in toxicity, and of little pollution. Polyacrylamide for tailings treatment.
However, the pH adjustment of flotation may have a significant impact on the mineral processing wastewater and inorganic components. If acidic or alkaline leaching is implemented, this effect will be aggravated. The existing chemical-mineral composition in the ore is the most important factor that determines the chemical properties of the mineral processing wastewater. The pH adjustment in the mineral processing may dissociate many components from the parent rock. Therefore, the pH value is often an effective indicator of the mineral processing wastewater composition Device.
According to the PH value, the tailings wastewater is divided into three categories: (1) Neutral simple washing and re-selection operations can cause such conditions, the pH value does not change significantly, and the chemical components in the wastewater are mainly limited to the parent rock Those components that are soluble at neutral pH may slightly increase the concentration of sulfate, chloride, sodium and calcium. (2) An increase in the pH of alkaline wastewater may also lead to an increase in the concentration of sulfate, chloride, sodium and calcium.
Although there are some metal contaminants, there is often no widespread activity of high concentrations of cationic heavy metals. (3) Decreasing the pH value of acidity increases the balance level of many metal pollutants. Acid leaching wastewater may show high levels of cationic components such as iron, manganese, cadmium, selenium, copper, lead, zinc and mercury. Acidic wastewater also shows an increase in the concentration of anions like sulfate and/or chloride.
In addition, there are specialized types of wastewater. Acidic and alkaline leaching of uranium may dissociate radioactive radium and thorium. If waste water is to be discharged from the tailings pond, the method of neutralization of lime and (or) barium chloride co-precipitation must be used to reduce the radium concentration to a lower level. If gold-silver is leached or lead and tungsten are floated, cyanide is a toxic component. Cyanide is relatively unstable and quickly degenerates into a low-toxic form of cyanide in the presence of oxygen.
The mechanisms of natural cyanide degeneration include acidification, CO 2 absorption and volatilization in the air, photolysis, oxidation and biological decomposition. These processes ultimately reduce the concentration of cyanide in the tailings pond wastewater, but it may take a long time. It depends on the concentration level of cyanide. There is also a toxic wastewater containing arsenic. In the case of arsenic and ore symbiosis, the process of beneficiation causes arsenic to dissociate in the waste water. For gold-bearing arsenopyrite, arsenic must be removed by roasting in order to be effectively leached, and then discharged to a suitable place, preferably not discharged Into the tailings pond.
A large amount of beneficiation wastewater is produced in the mining production, which has the characteristics of large discharge, complex composition, high suspended solid content, more harmful components and low concentration. If the beneficiation wastewater is not treated in time, it will inevitably produce the surrounding environment of the mining area. The harm also caused a great waste of water resources. Coagulation is one of the commonly used methods in water treatment and is often used in the treatment of mineral processing wastewater. Experience has shown that polyacrylamide flocculant is better for the treatment of mineral processing wastewater. Polyacrylamide for tailings treatment, the use method of polyacrylamide in mineral processing wastewater:
1. Dissolution: The dissolution concentration is 0.2-0.4%, and non-ferrous containers should be used. Use clean water below 60℃, while stirring, slowly and evenly sprinkle the flocculant into the water, so that the flocculant will be fully stirred with the water in the container. It can be used after 60 minutes of continuous stirring. It can be extended when the water temperature is too low. The mixing time and the linear speed of the mixing blade depend on the container.
2. Adding: Dilute the dissolved polyacrylamide flocculant for tailing water with clean water, and use a concentration of 0.05-0.1%. Use a valve or a metering pump to control the flow and add it to the tailing water evenly. (You can also Directly prepare a solution with a concentration between 0.02-0.1%).