Relationship Between Flotation Effect And The Surface Tension Of Slurry

The deterioration of flotation effect is more and more obvious with theexistence of the higher content of fine coal in coal separation. Coal slimeflotation is the important link of coal separation, and a reasonable system offlotation reagents is the key to realize the efficient coal slime flotation. In thispaper, we studied the relationship between flotation effect and the slurry surfacetension, and carried on industrial analysis, element analysis, particle sizeanalysis and XRD analysis with four coal samples of different metamorphicdegree. We found that the-0.045mm graded content in the coal sample is large,and the ash content is high. The samples are easy to mud. The basicallyassociated minerals in the coal samples are the same, including kaolinite,montmorillonite, quartz and pyrite.We chose the Pingshuo weakly caking coal as the main research object,supplemented by XRD analysis, to study the influence on surface tension ofslurry concentration, coal sample grain size and density, associated mineralcomposition and content. The results show that the surface tension is the lowestat the slurry density of100g/L. The surface tension of coal slurry is proportionalto the particle size, inversely proportional to the density and ash content. Kaolinhas a greater influence on the surface tension of slurry, and with the increase ofthe content of associated mineral the slurry surface tension decreases. Pyrite haslittle impact on the slurry surface tension. To study the effect of flotation reagents on slurry surface tension, usingkerosene, diesel oil as collector and2-octyl alcohol, QPJ as foaming agent,under the condition of different agent combinations and different dosage ofreagents, we carried on surface tension experiments of the Pingshuo weaklycaking coal, Malan coking coal and Jincheng anthracite coal. The results showthat when the dose is at right amount, collecting agent and foaming agent canreduce the surface tension of the slurry, and with the increase of the dose, slurrysurface tension decreases.The excess collecting and foaming agent cause theslurry surface tension rebound a certain degree. The reduced range of the slurrysurface tension is connected with the property of coal samples and reagentcombination. The minimums of surface tension of weakly caking coal, cokingcoal and anthracite coal under0.125mm slurry are58.18mN/m,58.03mN/m,58.71mN/m, and the minimums of surface tension of weakly caking coal,coking coal and anthracite coal slurry under0.5mm are58.94mN/m,58.26mN/m,58.68mN/m; The reagent combination of kerosene-2-octanol alcohol,in most cases, to reduce the slurry surface tension has better performance.We carried on flotation experiments of-0.5mm weak caking coal, cokingcoal and anthracite coal, and connected the ash of fine coal and combustiblerecovery rate to slurry surface tension by agent dosage to study the relationshipbetween the floatation effect and the slurry suface tension. The results show thatwhen the kerosene or2-octyl alcohol consumption is at right amount, with theincreaseing of reagents dosage, the slurry surface tension is reduced, and thecombustible recovery and ash content of fine coal is increased. They reach theextreme value point at the same agent dosage, and remain near the extremevalue point in the same agent dosage range. When the kerosene or2-octanolalcohol dosage is over-dose, with the increase of agent dosage, the slurry surfacetension rises again, and the combustible recovery rate and ash of fine coal fallback.The results have important significance on using slurry surface tension toguide the system of flotation reagents and assist in controlling flotation combustible recovery rate and ash of fine coal online.