The Primary Research On Extending The Upper Particle Size Limit For Coal Flotation

In this dissertation, selected xiqu coal and ximing coal as objects, research on flotation characteristic of coal with upper size limit to 1mm was conducted. The law of physical and chemical conditions on the influence of coarse coal flotation was inspected. On the other hand, through the narrow particle flotation kinetics experiments .The effect of rotational speed in flotation and air-flow rate on flotation dynamic kinetic constant and visual analysis of flotation dynamic was investigated. Finally theoretical analysis further demonstrated the feasibility of coarse flotation.The availability of such a technology developing methods of extending the upper particle size limit for coal flotation would improve processing efficiency. Two different complementary approaches would be used to achieve that. One is to use novel coarse coal flotation reagents that will help increase the attachment force between air bubbles and coal particles, and the other is to develop a new flotation machine specifically designed to promote coarse particle flotation.In this experiments, the rules of air-flow rate, rotor velocity and pulp density on the influence of clean coal recovery was inspected primarily with different size of xiqu. Experiment results showed that for -0.5mm fine coal ,the yield of flotation concentrate increased rapidly with the increase of air-flow rate when the impeller speed was low( less than 1500rpm). When the rotor velocity became high, The recovery of flotation concentrate increased slowly with the increase of air-rate. For +0.5mm coarse coal, in no more than 1500rpm rotational speed, the recovery of clean coal increased slowly in the amount of air-rate increase .When rotational speed was more than 1500rpm, the recovery of clean coal declined with the increase of air-rate. In particular, for 0.71-1mm coal, the laws had become more obvious. The effect of the clean coal recovery became low with the decrease of pulp density(60-120g/l) for -0.5mm xiqu coal and the yield of concentrate was higher with the increase of slurry density . Along with increase in size of flotation feed(0.5-lmm), the yield of concentrate became increased to a rate after decreased ,when the slurry density was raised.On the research of coarse coal flotation agent , primarily high-molecular flocculants (such as different molecular weight PAM and PEO) was added in flotation of 0.5-0.71mm,0.71-1mm xiqu coal and ximing coal. The experiments results showed that these flocculants wasn't suitable for coarse coal flotation analysis of effects on clean coal recovery and ash and tailings ash. Secondly selected a few surfactants as experimental objects . The conclusion was that these surfactants took effects on the coarse coal flotation. The proper reagent and proper dosage was important for coarse coal flotation.Research of flotation kinetics characteristics in 0.5-1mm particle size showed that low rotor velocity with high air-flow rate and high rotor velocity with low air-flow rate was useful for coarse coal flotation, when other conditions were invariable .The proper dosage Oleic acid added in coarse coal flotation It could enhance the recovery of clean coal as well as the flotation process speed.