| A large amount of high iron sulfide ore will be produced in the beneficiation process of sulfide mines,and its sulfur-containing minerals are mainly pyrite（Fe S2）.At present,the main utilization method of this kind of ore is roasting it to produce sulfuric acid,but this method is very easy to produce toxic gas and does not make effective use of the iron resources.Therefore,it is important to develop environment-friendly and efficient technology to realize the comprehensive utilization of high iron sulfide ore.In this study,a variety of extreme acidophilic iron sulfur oxidizing bacteria for artificial combination were used to efficiently bioleaching high iron sulfide ore of a sulfide mine in northern Guangdong.The effects of different temperature conditions on the leaching process of artificial microbial community were discussed,and the influence mechanism was analyzed.In addition,the comprehensive utilization of bioleaching solution was studied.Polymerized ferric sulfate was obtained by adjusting the initial p H of the bioleaching solution,reaction temperature and reaction time。And the application of self-made polyferric sulfate in the treatment of simulated wastewater and actual high turbidity wastewater has good flocculation effect.Firstly,the effects of constant temperature bioleaching（30,40°C）and variable temperature bioleaching（diurnal temperature range of 10°C）on the bioleaching of high iron sulfide ore by an artificial microbial consortium（including ferrous oxidizers（L.ferrooxidans and F.acidiphium）,sulfur oxidizers（A.thiooxidans,A.caldus）and ferrous/sulfur oxidizers（A.ferrooxidans and S.thermosulfidoxidans））were studied.The results showed that the artificial microbial consortium can effectively bioleaching high iron sulfide ore,and the bioleaching efficiency is more than 9 times higher than that of abiotic acid leaching.However,the temperature has a significant effect on the bioleaching process of sulfide ore.Among them,the diurnal temperature range has an obvious inhibitory effect on the bioleaching efficiency,although this effect was mainly concentrated in the early and middle stages of exposure,gradually decreasing until almost disappearing in the late stage.EPS analysis showed that the diurnal temperature range has a great influence on the production behavior of EPS in artificial microbial community during bioleaching,especially inhibiting the initial release of EPS.However,the continual increase in EPS secretion in the bioleaching system gradually reduced the adverse effects of diurnal temperature range on mineral dissolution.XRD,FTIR and SEM analysis of the bioleaching residue showed that the change of temperature did not change the inherent step-by-step oxidation law of minerals.Next,the preparation conditions of polymerized ferric sulfate produced by the polymerization of bioleaching solution of high iron sulfide ore were studied.The results showed that polymeric ferric sulfate with better flocculation effect could be obtained under the operating conditions of initial p H 2.0,reaction temperature between 40-50℃and reaction time between 1-2 h.XRD,FTIR and SEM analysis showed that the self-made polymeric ferric sulfate was mainly an amorphous,hydroxyl bridged polymer of iron.The results of flocculation comparison test show that the self-made polyferric sulfate has obvious advantages compared with the commercial polyferric sulfate at low dosage.In addition,the self-made polyferric sulfate was used to treat the backwash wastewater of the filter,which achieved good flocculation effect,up to 99.06%of the turbidity removal rate.Based on the research results,the selection of microorganisms with strong temperature adaptability and the increase of early temperature control measures are conducive to the early start-up process of artificial microbial consortium.In addition,polymerized ferric sulfate with good flocculation performance can be prepared from the bioleaching solution of high iron sulfide ore,which can be reused for the wastewater treatment of the mine,so as to turn waste into treasure and treat waste with waste.This study can provide theoretical basis and data support for the integrated treatment of environmental pollution prevention,control and treatment of sulfide mines in northern Guangdong. |
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