New Technology Of Treatment Of Wastewater From Pyrite Benification By Ozone Oxidation And The Mechanism

In the situation of increasing water resources shortage in our country, to recycle wastewater of mineral processing as much as possible is a trivial matter to every mining enterprise. But residual flotation reagents in mineral processing wastewater not only result in environrnent problem but also affects the reuse of wastewater. Therefore, it is necessary to develop effective methods to remove the residual reagents.The degradation behaviour of four common flotation reagents (butylxanthate, diethyl-amino-xanthate, sodium humate and turpenine) under the ozone oxidizing condition, and the effect of pH, ozonation time on removal rate of these flotation reagents has been investigated. It showed that ozone can remove butylxanthate, diethyl-amino-xanthate, sodium humate and turpenine from water effectively when ozonation time reached 15min, and the removal rate of butylxanthate and diethyl-amino-xanthate can be approximate to 100%. The removal rate of four reagents is in the order of diethyl-amino-xanthate > butylxanthate > turpenine > sodium humate. The removal rate of butylxanthate influenced by pH is the lowest, which always close to 100% at each initial pH. The optimum pH to remove other three reagents from water by ozonization is 8-10. The degradation mechanism between butylxanthate and ozone has been discussed. It can be inferred from ultraviolet spectrum, HPLC-MS, COD, etc., that SO₄^2- is produced. The COD of butylxanthate solution declined dramatically, the removal rate of COD reached 72.21% when ozonation time is 60 min. And the biodegradability (BOD/COD) of butylxanthate solution increased markedly and shifted from 0.251 to 0.361.On the other hand, to treat industrial wastewater of Tieling Flotation Reagents Factory and mineral processing wastewater of Fankou Lead-Zinc Mine, by the method of ozone oxidizing combined with others, were investigated. The results indicated that ozone oxidizing method can remove flotation reagent and COD from wastewater, and improve the quality of effluent significantly. In addition, the effects of untreated and treated overflow of zinc tailing on lead-zinc flotation were tested respectively. The results illustrated that the method combined ozonation treatment with chemical precipitation can remove metallic ions and flotation reagents from wastewater of zinc tailing effctively. It eliminated the minus factors to flotation, extended the treatment technology for mineral processing wastewater. Reuse treated wastewater did not influence flotation, the mineral processing indexes using treated wastewater was comparable to that using fresh water. It made recycling mineral processing wastewater possible.