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The Research Of The Impact Of The Pulp Viscosity On Grinding Efficiency Of Exi High Phosphorus Oolitic Hematite

Posted on:2012-02-18Degree:MasterType:Thesis
Country:ChinaCandidate:B WangFull Text:PDF
GTID:2131330335999692Subject:Mineral processing engineering
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Exi high phosphorus oolite hematite has not been used as a potential ore resource because the particle size of the ore and impurity existed is too small so that the size of mineral dissociation is only several microns, besides phosphorus content in the ore is also relatively high. During the super-fine grinding, vacancy of the particle decreases and in turn improve the difficulty of grinding after the particle size degraded to micron scale.How to dissociate the target ore and gangue with small price is really a problem resolving benefication technology of Exi iron ore. So, we mainly did researches on 2 aspects in this paper: influence factors of pulp viscosity,grinding test of grinding aids both of which will improve grinding efficiency and meantime reduce the developmental costs.The result of research on viscosity influence factors showed that:the main influence factors included the concentration of pulp,particle size,temperature and shear rate of pulp. Actually concentration is the remarkable factor, which have a rising exponential relation to the influence on viscosity of the pulp, from the tests we know that the optimum concentration of pulp is controlled at about 50%; what'more, size has a remarkable impact on viscosity, in the process of super-fine grinding, pulp viscosity increase with the particle size becoming smaller which in turn lower grinding efficiency; the impact caused by temperature is not remarkable in the coarse particles, but is going to becoming outstanding when the particle size of pulp become smaller.Shear rate will also influence the viscosity significantly, the result shows that viscosity declines with the shear rate rising, moreover the falling trend will be notable at the first stage of increase of shear rate, when the rate is more than 1000s-1, viscosity begin to decrease gradually, yet rising the rotating speed of the mill can reduce viscosity of pulp.Grinding tests of grinding aids suggest that:in the normal ball-milling tests, grinding aids Hexametaphosphate and sodium tripolyphosphate have efficiently reduce pulp viscosity and remarkably increase the grinding efficiency, however with the time going on, the effect of grinding aids decrease. From the result we know 5mins after grinding will bring the best effect, the content of-38um increases 5.75% on average, and both will lead to decrease of energy-consumption, adding 0.2% of the 2 aids and get the same size of grinding products, energy-consumption of the mill decreases 34.58% and 37.65% respectively.In the grinding test using high energy agitating mill, the content of d50 and d90 reduces accordingly after adding 0.4% of the grinding aids, viscosity increase exponentially when pulp size become smaller and smaller. Adding Hexametaphosphate, generation ability of 10μm part in the mill increases remarkably, however more grinding time, less increase of specific productivity. Furthermore, adding grinding aids will raising the utilization ratio of energy, when the d90 part is grinded to 10μm,8μm,5μm this 3 size ranges, energy-consumption declines 34.5%,28.2%,22.4% after adding grinding aids.
Keywords/Search Tags:Exi high phosphorus oolite hematite, Viscosity, Fine-grinding, Grinding aids
PDF Full Text Request
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