Feasibility Study of Depyritization of Coal Using Bioflotation

Sulphur is one of the waste elements in coal material which is in two forms, organic and inorganic. The amount of sulphur more than acceptable quantity in coal concentration affects the environment and coke characteristics. The quality of steel is depended on the quantity of sulphur in coke. High sulphur in entering materials to the steel furnace causes inferior steel. Also, sulphur in heat coal makes SO2 gas which has negative environmental effects. Different chemical, physical and biological techniques are investigated for removing sulphur from coal. In recent years, new method for desulfurization from coal is expressed with improving biotechnology and microbial mining. In this research, feasibility study of depyritization from Tabas coal using bioflotation method in laboratory scale was considered. In these tests, Pyrite in coal pulp depressed with desulfurization bacteria. To carry out bioflotation tests, a sample from C1 seam (Tabas, Parvadeh Mine, no. 2) was used. After comminuting and screening, the coal material less than 500 micron was used as flotation feed. A Thiobacillus ferrooxidans bacterium was obtained from the biotechnology laboratory at Sarcheshme Copper Mine. Thiobacillus ferrooxidans was cultured in 9K medium. Bioflotation tests were carrying out in Denver flotation cell and the important parameters such as pulp density, particle size, bacterial density and interaction time were optimized. Final results indicated that by using the mentioned method, the pyritic and total sulphur were decreased about %62 and %35, respectively.