| In this paper, using the slime water of Xinzhuangzi Coal Preparation Plant as the research object, based on the property of slime and mineral composition, an overall analysis of the characteristics of coal slime is given under the condition of different reagents, concentration, reagents conbination or pH values. The influence of several common coagulants on flocculation ability is analysed, and the relationship between the conductivity, hardness,ξpotential and pH of slime water and transmittance is also discussed. we predict the flocculation ability of the coal slime water by the conductivity, and test its credibility by regression equation and mathematical model.In the flocculating settling experiment, the best sequence of effect of different coagulants on flocculation ability are as follows:PAC>KAl(SO4)2>CaCl2>MgCl2> CaSO4. Among them, calcium magnesium salt is almost impossible to reduce the pH value of coal slime, while aluminium salt can significantly reduce the pH value. It is found that calcium magnesium salt have effects mainly through changing and destroying the double electrical layer structure of coal slime. Aluminum salt have effects through compressing or adsorbing electric neutralization and Al (OH)3 colloid adsorption to slime particle slime and settlement. So its function mainly reflects in the aspect of compressing electric double layer structure.Under the condition of unchanged coagulant dose, the influence of different pH value on slime water condensation performance is discussed. The results show that the alkaline environment is favourable to settling calcium magnesium salt, which is mainly three-phase adsorption. The acidic environment is favourable to settling aluminum salt, which is mainly multi-hydroxyl aluminum salt adsorption. Moreover, by the infrared spectrum, we analysis the spectrums of coal slime with different pH values, pointing out that the pH values mainly affect-OH group and the ash zone with 1030cm-1 of fingerprint zone.According to the slime water treatment experiment with three different flocculants, this paper set up different types of polyacrylamide adsorption model with slime water flocculation. It shows that there are mainly hydrogen bonding adsorption of amide group in non-ionic model, amide group and-COO-group in anionic model, and chemical electrostatic force in cationic model. Meanwhile, we consider the influence of flocculant with the different molecular weight on flocculation effect of slime water. The larger molecular weight, the better characteristics of Settlement. Therefore, combined with the changes of slime water concentration in actual production, we determine the coagulant and flocculent dosage in different slime water concentration by even compound experiment. The concentration of slime water is 50g/1-90g/l in the Xinzhuangzi Coal Preparation Plant. When PAC is used as coagulants, the addition is 30g/m3-80g/m3, and the addition of flocculants is 2.5-6g/m3. When CaSO4 is used as coagulants, the addition is 120g/m3-200g/m3, and the addition of flocculants is 2.5-6g/m3.Besides, this paper also discusses the properties of coal slime that below 200 mesh in slime water, and set up the exponential regression equation of wetting angle and ash content. The results show that under the condition of the same medicament dose, with the increase of the ash, the surface property of slurry will vary obviously while flocculation effect will be bad.Figure 46; table 13; reference 66... |
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