Basic Studies And Industrial Practice Of Treatment And Reuse Of Wastewater Of Fankou Mill

Water resource has become the well-known problem in the world because it is closely related to human life and environment. A lot of water has been consumed and wasted in mining to obtain metal resources, which also play a very important role in human society development. The wastewater produced in mineral processing contained a lot of suspended solid particles, heavy metal ion, flotation reagents, organics and other pollutants etc, resulting in waste of water resource and environmental pollution. Wastewater treatment and recycled use, therefore, are very important.Fankou Lead-Zinc Mine is the largest one in China. Although it conducted the research of wastewater treatment and reuse as early as in 1970s', it has never industrial application because the wastewater has a very harmful effect on the production even after treating the wastewater. Fankou Lead-Zinc mill has been operating using new water about 7.5 million m~3 each year from Bai Jiang River and discharged corresponding wastewater. Not only wasted the water resource was but polluted the environment around the Fankou Mill was.In this PhD dissertation, the treatment of waste water from Fankou Mill, the effect of recycled water on the flotation of lead-zinc-iron sulfide minerals, the interaction mechanism of flotation reagents with the minerals and the formation of surface species in recycled water and waste water recycling technologies have been investigated in order to reuse the waste water in industrial production of Fankou Mill.The effects of solid concentration, dilution and flocculant type or dosage on settlement of wastewater have been tested at first. It followed that the settling time of wastewater was increased with the increase of solid concentration, dilution and addition of flocculants decreased the settling time. The dosage of flocculant required being less than 5g/t in order not to affect flotation process. The treatment of wastewater was further tested using high efficiency thickener to obtain the optimal parameters for industrial application. The effect of physicochemical atmosphere such as water hardness, ion strength, residual flotation reagent etc. on flotation behavior and rate of sulfide minerals has been tested. It underlay the basics for water recycling technology.The interaction mechanism and surface species formation between residual collector, metal ion and galena, sphalertie and pyrite have been revealed based on the electrochemical measurement and FTIR analysis. The effect of metal ion on the structure of energy band of sphalerite has been calculated in the light of quantum chemical calculation. The digital camera technology was used to identify the bubble distribution in order to analyze the effect of residual frother in recycled water. It has been innovative proposed to use the recycled water according to their characteristics and different water recycle based on these studies.The lab bench flotation tests and pilot plant flotation experiments for flotation separation of Fankou lead-zinc-iron sulfide ore in recycled water have been conducted. The new invented technology succeeds. The recycle and reuse of wastewater has operated into the Fankou plant production. It benefited greatly from the new technology.