Intermediate Experiment on the Recycling of Coke Plant Effluent through Washing Water Closed Circuit System in Coal Preparation Plant

Washing coal usually brings about 0.2m3/t wastewater (in terms of closed circulation) due to transpiration, which provides an effective space for the recycle of coke-plant wastewater. The effluent from phenol-cyanogen wastewater biochemical disposal station is used as complementary water for washing coal, and Closed-Cycling System in coal preparation plant is introduced to make industrial experiment. Results show that we can use coal power adsorption and flocculation as well as sedimentation to treat the contamination which is hard to be decomposed biologically in coke-plant wastewater, and the concentration of contamination in circulatory water tends downward. During 42 hours´ washing coal experiment, no evidence shows there are negative effects on main wash, dielectric removal, magnetic separation, floatation and inspissation, which validates the feasibility of the new technique with zero-discharge of coke-plant wastewater in the circulation. The use of washing water closed-cycling system in coal preparation plant can effectually improve the adaptability of biological treatment of coke-plant wastewater to the fluctuation of wastewater´s quality and quantity, improve the system´s stability and its economic rationality, avoid the environmental pollution brought by wastewater discharge (within the standards), and effectively increase the wastewater´s recycling rate.