| Tribo-electrostatic separation is an efficient,less pollution and no water dry mineral processing technology.More and more people are concerned about it,when global water scarcity and pollution are serious.Tribo-electrostatic separator is the key to achieve the choice of Tribo-electrostatic.After years of development,it has been developed a variety of tribo-electrostatic separator at home and abroad.but there are still less charged,the charge is not sufficient,the processing capacity is small,easy to wear or mineral attached to other issues.China is a large country of phosphate resources,but most of the low-grade phosphate ores,the need to improve the quality of mineral processing or removal of impurities to become qualified concentrates,the current widespread use of flotation method of high cost,pollution and other issues,need to be improved.Although China is a large country of phosphorite resource,most of the phosphate ores is the low-grade.In order to obtain qualified concentrates need to mineral processing or remove impurities.At present,flotation method uses widely,but there are problems of flotation like high cost and pollution need to be resolved.Tribo-electrostatic separation has been shown to be adapted to the processing of phosphate ores.The paper has important theoretical and practical value in the development of new type of Tribo-electrostatic separation with the advantages of phosphate rock resources around Yunnan plateau lake.The friction device is the core part of the tribo-electrostatic separator.By analyzing the advantages and disadvantages of the existing friction devices,there are three kinds of high efficiency airflow friction devices are developed,such as impact type friction device,inclined plate type friction device and jagged wave type friction device.The tribo-electric charge test was conducted using apatite and quartz pure minerals.The results show that the three kinds of friction devices,the apatite and quartz can be charged,and the apatite is positively charged,the quartz is negatively charged.The airflow velocity and the heating temperature can significantly affect the charge-mass ratio,while in the smaller range,the effect of the feed amount is small.The charge of the impact type friction device is better in the high airflow velocity.The advantages of the inclined plate type friction device are shown in the low airflow velocity range.Jagged wave type friction device in the higher air velocity can achieve a better charge effect,but still not same as impact and inclined plate type two friction devices.The inclined plate type friction device is good friction charge,because it has big charge-mass ratio per unit volume.The impact type friction device is also a good friction device,it's charge-mass ratio per unit volume is small,the internal surface area is small,the internal friction plate area is smaller,and the best charge-mass ratio is big,but the utilization of the internal space to be improved.The internal surface area and the internal friction plate area of the jagged wave type friction device are large,but the charge-mass ratio per unit volume is small,and the feeding amount is relatively small,so it is relatively poor.Basing on the impact type friction device,the sorting device uses the parallel electrode plate,the feeding device chooses screw feeder,and it uses the bag filter as the product collection device,developed a new type of tribo-electrostatic separator for conveying ore particles by airflow.The results of triboelectric charge test for low-grade phosphate ores in Yunnan Dianchi area show that the original ore assaying P2O5 22.16%,SiO2 33.31%,adding 1%of toner grind to-200 mesh accounting for about 85%.After Preheating at 110? for 24 h,through one rough,two cleans and one scavenge,the test can be obtained the concentrate assaying P2O5 29.24%with recovery of 71.45%of the phosphorus and the middlings assaying P2O5 22.03%with the recovery of 13.14%.The total recovery of 84.55%,the tribo-electrostatic separation got better indicators. |
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