Experimental Research And Mechanism Analysis On Flotation Regaents Optimization Of Oxdized Coal Slime

Nowadays, flotation is a primary separating technology for coal in our country. Based on the well hydrophilic and poor flotability of oxidized coal slime, conventional reagent has a series of disadvantages, such as low efficiency and excessive consumption of reagent. Therefore, seeking cheap efficient flotation reagents which can improve the conventional collector performance and reduce the dosage of collector is one of the basic ways to reduce difficult oxidized coal slurry flotation costs and realize the reasonable utilization of resources.Oxidized coal slime was made under the conditions of Low-temperature and drying. The conditions are easy to operate and control accurately, which meet the requirements for laboratory safety and the coal slimes have representative characteristics.Oxidized coal was measured and analyzed by FTIR. It was shown that the content of hydrophobic decreased, while the hydrophilic increased, which leads to the Zeta-potential to negative direction on the surface of oxidized coal slime.According to the characteristics of oxidized coal slime, there are several oleicacid surfactant based on the previous research, such as Span80、 ODEA、PEG400DO、FM、9858 and Oxidized paraffin wax soap. The compound collector was made by adding the selected surfactants to kerosene or water respectively. The flotation experiments were carried out on Malan and Tunlan oxidized coal slime. And the flotation test on similar coal was done to verify it. The pH adjusting agent, inorganic salt, reducing agent were also used in the process of flotation. The acceleration and function mechanism of part accelerator in flotation were explored.As one kind of flotation collectors,9858 can make the combustible recoveries reach 88.87%. Whlie as composite collector, Span80、ODEA make the yield increase to 82.2% and 78.08%, which has a promoting effect on oxidized coal slime. FM and oxidized paraffin wax soap can dissolve in water, both of them have promoting effect on Malan oxidized coal, but for Tunlan oxidized coal which is not obvious. It has certain effet on Malan oxidized coal slime by using kerosene which mixed with PEG400DO, but not for Tunlan coal.Organic reductive VC can promote the flotation of coal slime when in the slurry pH=5, the yield cleaned coal is 42.20%, while ash content is only 6.99%. Inorganic reductive Fe2+ at low dosage can also promote the flotation of coal slime, but the effect is not significant. The flotation index is optimum under pH=6, but the flotation index decline if increase or decrease the pH value of coal slurry.The chemical adsorption occur between the oxygen-containing functional on the surface of oxidized coal, which reduce the number of—OH, and increase the hydrophilicity of the coal surface, thus increasing the contact angle of coal slime and improving the floatability.