Study On Slective Flocculation Characteristics Of Coal Slime

In order to improve the disadvantages of flotation process with high coal slime ash and low yield, selective flocculation experiments of Inner Mongolia fine coal are conducted. Firstly, pure mineral’s dispersing and flocculation experiment conditions are conducted and screened out the best dispersants and flocculants as well as test conditions and then on this basis, artificial mixed ore’s optimum dispersion and flocculation conditional experiments are conducted.Finally, analysises are made on flocculation mechanism of coal and kaolinite by means of dynamic potential and infrared spectroscopy.Four kinds of dispersants’ s experiments are conducted and come to a conclusion that when pulp density is 20g/l,citric acid dosage is 24mg/l, sodium silicate dosage is 20mg/l, sodium polyp Hosp Hate dosage is 16mg/l, sodium hexametap Hosp Hate dosage is 20mg/l, and each agent is under the p H of 6, the dispersing effect difference of two minerals is maximum. By comparing the optimum conditions of four types of agents, the result shows that the dispersion effect of four types of agents on kaolinite is: citric acid> sodium hexametaphosphate > sodium polyphosphate > sodium silicate; the dispersion effect on coal is: sodium hexametaphosphate >sodium silicate >sodium polyphosphate > citric acid. Combining the dispersion effect of each agent on two minerals, the citric acid is the best. Four types of flocculating agents’ s experiments are also conducted and the result shows that when dextrin dosage is 20mg/l, calcium chloride dosage is 110mg/l, aluminium chloride dosage is 110mg/l, aluminum potassium sulfate dosage is 20mg/l, and they are all under the p H of 6, the selective flocculation effect of coal and kaolinite is good. Finally, aluminum potassium sulfate is best as flocculant by comparing the optimum effect of each agent.Separating the artificial mixed mineral(the ash is 35%) under the best condition of dispersion and flocculation,gets that when pulp density is 35g/l, dispersing agent citric acid dosage is 20mg/l, flocculating agent aluminum potassium sulfate dosage is 140mg/l and the p H is 6, the clean coal can be obtained with bottom flow ash 14.3% and recovery rate 59.65%, and the selective flocculation is good.Through infrared spectroscopic analysis arrives at a conclusion that there is no obvious change in kaolinite spectrogram after the agent added, and kaolinite and aluminum potassium sulfate are p Hysical adsorption. New absorption peak of coal appears in 3580cm-1 and this place may be absorption peak of hydroxyl. Other absorption peaks move around the original position, and the absorption of coal and aluminum potassium sulfate is chemical adsorption.Through dynamic potential detection, the conclusion is that the absolute value of kaolinite and coal electric potential is decreasing gradually. Only when the p H is 6, the kaolinite Zeta electric potential absolute value changes slightly. The coal changes greatly and the electric charge absorption may occur between coal and agent.