Experimental Study On Separation Of High-sulfur Coal Gangue

Coal gangue is the major industrial solid waste in China.At present,the stock of coal gangue in China has exceeded 5 billion tons,and it is still increasing at an annual rate of 3 billion tons.The massive accumulation of coal gangue not only occupies a large amount of land,but also seriously pollutes the environment.Therefore,realizing the resource utilization of coal gangue not only protects the environment,but also plays an important role in achieving sustainable development of society.The study of the ore sample is the coal gangue from Anning,Yunnan.The main valuable elements are C and S.The fixed carbon content is 11.39% and sulfur content is 5.24%.Carbon is mainly in the form of graphite and sulfur is mainly in the form of pyrite and gangue minerals are mainly quartz,sericite and kaolinite.The structure of the coal gangue are loose massive and plate structure.The distribution relationship between the target mineral carbon and pyrite and gangue minerals is complex,and the particle size is fine.The calorific value of the raw ore is low,and it belongs to low carbon and high sulfur refractory gangue.According to the characteristics of raw ore,the principal flowsheet is obtained through a large number of exploratory tests: It is recommended to use jigging separation after crushing raw ore to obtain light minerals and heavy minerals,and coal concentrate can be obtained by flotation of light mineral products,and qualified sulfur concentrate can be obtained by shaking table separation of heavy mineral products.The raw ore is crushed to-3mm.The jigging test can achieve yield of 82.00%,C grade of 11.77%,S grade of 3.16%,C recovery of 84.74%,and S recovery of 49.45% of light mineral product and yield of 18.00%,C grade of 9.66%,S grade of 14.72%,C recovery of 15.26%,and S recovery of 50.55% of heavy mineral product.Jigging light mineral products grinding to-200 mesh 80%.Using calcium oxide and sodium silicate as inhibitors,and diesel oil as collector,and 2 # oil as foaming agent,coal concentrate with yield of 18.48%,C grade of 30.27%,sulfur content of 1.50%,and recovery of 49.12% can be obtained by the closed-circuit flotation process of "three roughing,one scavenging and three cleaning,and medium ore returning sequentially".Jigging heavy mineral products grinding to-200 mesh 75%,and carrying on one stage shaking table separation.The first stage medium ore grinding to-200 mesh 80%,and carrying on two stage shaking table re-separation.It can achieve the sulfur concentrate with yield of 4.87%,sulfur grade of 47.81%,carbon content of 1.41%,sulfur recovery of 44.42% which reaches the standard of first-class sulfur concentrate.The whole process of expanding the test shows that with jigging pre-selection,jigging light minerals flotation and jigging heavy minerals shaking table separations process,it can achieve coal concentrate with yield of 18.48%,C grade of 30.27%,sulfur grade of 1.50%,and recovery of 49.11%.And sulfur concentrate with yield of 5.43%,sulfur grade of 47.02%,carbon content of 1.45% and recovery of 48.72%.The process effectively improves the coal content,and the sulfur concentrate reaches the standard of the first-class sulfur concentrate,which improves the reference for the comprehensive utilization of high-sulfur coal gangue.