Study On The Migration And Transformation In Flotation System Of Sulfur And Arsenic From Gold-copper Sulphide Ore

Taking a gold-copper mine as example,the paper studys on the migration and transformation in flotation system of sulfur and arsenic from gold-copper sulphide ore.By sampling and testing ore,concentrate,tailings and mineral processing waste water from flotation system,it showed distribution and migration of As and S in flotation system.The test results of tailings leaching toxicity and speciation analysis experiment evaluated stability of As in tailings.Using various means including chemical phase method,XRD and MLA explained phase constituting,binding configuration,occurrence and dissemination characteristics of S and As in ore,concentrate,tailings from flotation system.The main conclusion is as follows:1.Migration and distribution of S and As in flotation system:?1?The distribution ratio of S in ore in flotation system as follows: gold-copper concentrate>sulfur concentrate> tailings>loss>iron concentrate.The distribution ratio of As in ore in flotation system as follows: tailings> sulfur concentrate > gold-copper concentrate > iron concentrate >mineral processing wastewater> loss.?2?Results of Dold morphology extraction experiment of As show:in each ore T1 water soluble arsenic and T2 exchangeable arsenic content are extremely low;sulfur concentrate and gold-copper concentrate exist trace T3 hydroxyl oxidation state of As;there is trace amounts of T4 native iron oxide in iron concentrate;the content of T5 organic and the secondary copper sulfide state is very few in each mineral,but a certain amount of T6 the native sulfide state is contained,and most of the arsenic exists in T7 residual state.After the flotation process,trace amounts of arsenic were oxidized and released,but the main content of arsenic were not changed in the presence of T7 residual state.2.Arsenic in tailings is with high stability:?1?Toxicity leaching experiment results showed that the leaching value of arsenic in tailings is low,and there is no leaching toxicity temporarily.According to the definition of type ? general industrial solid waste in "General industrial solid waste storage and disposal site pollution control standards"?GB18599-2001?,only consider arsenic tailings belong to the type ? general industrial solid waste.?2?Because arsenic above 98% are residual state in tailings and carrier mineral of As provides a natural protective layer,so its occurrence status is more stable in tailings.The detection results of arsenic in tailings waste water are all lower than the detection limit of atomic fluorescence method,which is proved that the occurrence of arsenic is stable and arsenic is difficult to release into the environment under normal conditions.High stability of arsenic in tailings suggests the feasibility of the comprehensive utilization tailings.3.Phase constituting,binding configuration,occurrence and dissemination characteristics of S and As in gold-copper sulphide ore.?1?Sulfur in minerals are mainly in the form of magnetic sulfur,sulfate sulfur and sulfide sulfur.In raw ore,sulfur concentrate,gold-copper concentrate,iron concentrate and tailings,sulfur are mainly in the presence of sulfides.After the flotation process,sulfide enriched to sulfur concentrate and gold-copper concentrate and magnetic sulfur enriched to iron concentrate,so total sulfur content in tailings is greatly reduced.Arsenic in minerals are mainly in the form of arsenic trioxide,arsenate,sulfo-arsenides and other forms of arsenic.In flotation system,raw ore,sulfur concentrate,iron ore concentrate and tailings contain a certain amount of arsenic trioxide;sulfur concentrate,iron ore concentrate and tailings contain a certain amount of arsenate;raw ore,sulfur concentrate,gold-copper concentrate,iron concentrate and tailings contain a certain amount of sulfo-arsenides and arsenic in other forms of content is larger,the content is about 92%.?2?It's analysed by X-Ray Diffraction that the ore contains pyrite,chalcopyrite,bornite and siderite and gangue minerals quartz,garnet and calcite;sulfur concentrate contains pyrite,hematite and quartz;gold-copper concentrate contains pyrite,chalcopyrite,bornite,siderite and quartz;the gangue minerals in the tailings are mainly quartz,calcite,chlorite and andradite and the sulfide ore in tailings can be detected are sphalerite,galena and diopside.XRD pattern analysis of raw ore,concentrate and tailings,no arsenic independent ore phase.?3?It's showed by MLA that independent mineral by sulfur and arsenic coexistence in ore are enargite,arsenic tetrahedrite and arsenopyrite,wherein enargite mainly intergrow with chalcopyrite,pyrite and some wrapped in calcite,arsenic tennantite wrapped in quartz and arsenopyrite is mineral monomer or wrapps fine particles of pyrrhotite.After the flotation process,which transfered to concentrate is mainly tennantite intergrowthing with pyrite.Iindependent mineral in gold-copper concentrate are enargite,arsenic tetrahedrite and arsenopyrite.Enargite intergrowth with bornite and arsenopyrite is mineral monomer.?4?Release analysis of arsenic in sulfur arsenic ores: Arsenic trioxide compounds accounted for 2.39% of total arsenic in ore which may be generated by the oxidation of arsenopyrite by exposure to the natural environment.Part [AsS]^2- in arsenopyrite is oxidized to As??? or As???.In flotation process,Alkaline and oxygen enrichment have little effect on arsenic tetrahedrite and arsenopyrite,but the possibility of enargite oxidized and released is great.Surfac tailings are preferentially oxidized,this process may arsenopyrite or mineral carrier of arsenic is oxidized.