Study On Flotation Tailings Of Kaolinite-type Pyrite In South Of Sichuan Efficient Utilization

The pyrite resources are rich in south of Sichuan,the main minerals are pyrite and kaolinite.In the long term mining and beneficiation,many kaolin have not been fully utilized and abandoned in the tailings because mining and beneficiation technology lagged.Numerous pyrite tailings not only take up a lot of valuable lands,but also lead to serious acid mine wastewater pollution.Therefore.it has great significance for recycle development of coal and sulfur industry that make efficient use for kaolinite type pyrite tailings for the south of Sichuan.The mineralogical properties of kaolinite type pyrite tailings,carbonization and desulfurization process of gravity concentration kaolinite type pyrite tailings,flotation tailings is used for concrete mineral admixtures and surface modified calcined kaolin is used for rubber and plastics filler were studied in this paper.The main contents and conclusions of this paper are as follows:(1)The mineralogical properties of the gravity concentration tailings.Kaolinite type pyrite tailings for the south of Sichuan divide into two categories(gravity concentration tailings and flotation tailings),the main minerals are pyrite and kaolinite.Kaolinite type pyrite tailings contains anatase and calcite,gravity concentration tailings mix with some carbonaceous minerals.The content of SiO2 and Al2O3 in gravity concentration tailings is 59.35%,carbon and sulfur content are 6.27%and 7.84%.The content of SiO2 and Al2O3 in flotation tailings is 76.50%,carbon and sulfur content are 1.06%and 0.82%.(2)Gravity concentration tailings decarbonize and desulfurize flotation test.Gravity concentration tailings need to re-grinding to-0.074 mm 85%for flotation;Gravity concentration tailings' carbon and sulfur grade reduced to 1.28%and 1.03%after decarbonization and desulfurization flotation,;Carbon concentrate calorific value is 5285.68 kcal/kg(22.11 MJ/kg),sulfur concentrate grade is 48.63%,achieve the requirements of sulfur concentrate superior product;The carbon and sulfur grade of the decarbonization and desulfurization tailings is very close to the flotation tailings,and they can be used for concrete mineral admixtures.(3)The flotation tailings is used for concrete mineral admixtures test.Flotation tailings(-0.074 mm 85%)after calcination,become calcined kaolin,after grinding,calcined kaolin with high pozzolanic activity;The optimum calcination temperature is 800 ? the best calcination time is 2 h,as 90%of the flotation tailings' fineness is less than 19.64 ?m,cement mortar activity index is 125.6%in the optimal condition;When the proportion is 30%,the concrete has the best mechanical and construction performance,and the calcined kaolin can replace the cement clinker and reduce the hydration heat effectively;With the increase of hydration age,Ca(OH)2 produced by cement increases;At the same cement hydration age,Ca(OH)2 decreases with increasing proportion,and with the increase of proportion,active SiO2 and Al2O3 consume Ca(OH)2 rise(active SiO2 and Al2O3 can make secondary hydration reaction with Ca(OH)2)and occur obvious pozzolanic reaction.(4)Surface modified calcined kaolin is used for rubber and plastic filler test.Calcined kaolin by grinding(grinding particle size 60%? 2?m)and it is modified with silane coupling agents(the amount of 1.5%calcined kaolin's quality),the modified calcined kaolin can be used for EPDM rubber fillers and PP plastic fillers;The modified calcined kaolin can reinforce the EPDM rubber effectively,the best ratio of the surface modified kaolin is 15%M,tensile strength of rubber is 4.32 MPa,45.5%more than the blank sample;Rubber's elongation at break increased from 322.03%to 402.85%;the modified calcined kaolin can improve the mechanical properties of PP obviously,the best addition is 10%M,plastic's elongation at break increased from 28.15%to 51.29%;unmodified kaolin is poor for PP plastic compatibility,has no effect.Calcined kaolin that is prepared from kaolinite type pyrite tailings in south of Sichuan can be used for mineral concrete admixture and consume a large number of pyrite tailings in south of Sichuan.Modified calcined kaolin can be used for filler of the rubber and plastic and achieve the purpose of emission reduction.These methods not only can utilize resources,but also consume a large number of the tailings and achieve the efficient use for a large number of kaolinite type pyrite tailings in south of Sichuan.