METHOD OF SELECTING SURFACTANTS FOR WETTING OF BITUMINOUS COALS Russian patent published in 2001 - IPC

FIELD: mining; applicable in improvement of wetting efficiency of edge zones of coal seams by increased reliability of surfactant selection. SUBSTANCE: method includes preparation of bituminous coal samples of regular geometric shape; determination of their weights in air dry state and immersing of one sample to depth H_imm. into aqueous solution of surfactant from 3 to 24 h. Then depth of sample immersion into surfactant solution is determined. Excessive liquid is removed from sample surface and weight of wetted sample is determined and wetting angle θ is calculated. After it, measurements are repeated at least four times for successively increased concentration of surfactant. Wetting angle θ versus surfactant concentration graph is constructed. Similar procedure is used in research for other surfactants. The most efficient surfactant and its concentration are determined by graph θ=f(C) by minimal value of wetting angle for all curves. Wetting angle is calculated by formula , where ρ_l, ρ_app. are liquid density and apparent density, kg/m³; g is free fall acceleration; P_work. is working porosity; α_l-g is surface tension coefficient; S_jp. is capillary specific surface, m²/kg; Δ_m is specimen weight increment, kg; S_b is sample base area, m²; H_imm. is immersion depth, m. EFFECT: reduced labor input, higher accuracy and reliability of surfactant selection for provision of wetting efficiency of edge zones of shock bump or outburst-prone seams of coal. 3 dwg