خنثی سازی آبهای اسیدی معادن و کارخانه های کانه آرایی جهت استفاده مجدد

Envieonmental pollution is one of most important threatening factors to mankind in today’s industrial world. For this reason, environmental protection is one of most important issues which is considered as a preference by governments, politicians and law makers in different countries. Regarding chemical compounds in ores or minerals, chemical reagents used in mineral processing operations, and also the surface or used water in the mining or mineral processing sites, the water is contaminated by the available or used chemical substances. The necessity of the use of uncontaminated water, which has a suitable quality, in mines and mineral processing plants, and also considering relatively costly water supply in most areas where these mines and mineral processing plants are located, a proper solution, in most cases, is to recover the water by removing the contamination from it, and then reuse it. One of the most important contaminations of this kind, is the contamination by acid substances, which is naturally created by the oxidization of pyrite in gangues associated with extracted ores, or other factors. An important method to remove the contamination from the water is to use chemical reagents which neutalize the water. In this method, which is called active treatment method, chemical substances neutalizing acidic water practically play two essential roles: ۱) Reaction with the water to reach a desired pH (about ۷). In practice, pH of the treated water is obtained between ۸.۵ and ۹.۵ in most cases. ۲) Removal of acid substances from the water using certain industrial processes. Neutalization of the acidic water in the active treatment method is essentially made by adding some materials to the water, in which one of the most important of the materails is lime. Another method for treatment of contaminated water is the passive treatment method, which is not the main subject of this paper, but it is briefly explained here. In this paper, the materials used for is neutalizing acidic water, and the certain industrial processes for this purpose using the so-called materials, and thus, recovery of clean water for reuse are investigated in detail. Eventually, different materials, used for neutalizing acidic water, are compared from the efficiency and economical points of view. Based on this comparison, suitable materials and also proper processes for neutalizing acidic water in mines and mineral processing plants in Iran, have generally been suggested.