| With the rapid development of China's economy, so the demand for coal resources is increasing, taking into account the current shortage of high-quality coal resources. Low rank coal accounts for more than 55%of China's coal reserves, so how to develop and utilize efficiently it,become an important way to deal with the shortage of coal resources.Due to the low degree of low rank coal, combined with the increasing degree of mechanization of mining, so the yield of coal slime is much higher than that of middle and high rank coal, flotation is a very important method to realize the high efficiency and low pollution utilization of low rank coal slime. poor natural floatability and well-developed porosity, which results in the high consumption of the traditional hydrocarbon oil collector and low flotation efficiency,therefore, the development and utilization of low rank coal resources are limited. So to develop a new type of high efficiency low grade coal slime collector,to reduce the production cost and improve the separation effect,is a great significance for the development and utilization of low rank coal resources in our country.In this paper, through the PIT microemulsion technology to make PIT microemulsion collector; Then, for Shendong group Shenfu Dongsheng mine Buertai low rank coal, get the best flotation reagent system to the core, then compared with the traditional hydrocarbon oil collector; Finally, the flotation mechanism of PIT microemulsion collector was revealed by means of infrared spectrum analysis, XPS and contact angle analysis. The following aspects are the main contents and conclusions of the full test.(1) In order to determine the microemulsion Formula range, this paper focus on the types of surfactants, dosage and microemulsion type,by using the quasi-ternary phase diagram method and conductivity method and 0 # diesel oil as the oil phase, op-10 as the main surfactant.(2) Based on the range of microemulsion formula, the response surface method was used to optimize the design. The response surface data analysis and regression fitting were carried out, with the microemulsion particle size as the evaluation index. And the optimal formula was verified. Milk collector base formula: op-1018.25%, n-amyl alcohol 18.15%, 0 # diesel 35.5%, water 28%.(3) Aiming at the basic formula of microemulsion, it is indicated that the phase transition temperature is 80? by using the temperature conductivity method. This paper use the phase transition temperature method (PIT method) and the microemulsion particle size as the evaluation index. It is determined that the initial temperature of the PIT method is 78?, the particle size of prepared PIT microemulsion collector is 29.30 nm, which was 5 nm lower than that of the conventional microemulsion collector and remained stable for 8 months.(4) The flotation test of low-grade slime showed that the sorting index can be obtained that the yield of pure coal is 48.42%, the ash is 12.64% and the recovery of combustible body is 58.43% under the condition of the dosage of 2kg /t and the amount of foaming agent 0.2kg/t. Compared with the traditional hydrocarbon oil collector (0 # diesel),the yield of PIT microemulsion collector increased by about 13% , The recovery rate of combustible body increased by about 16%, the amount saved by 66.67%, and the amount of foaming agent savings of 71.67%.The combined cost of PIT microemulsion collector is only one third of the 0 # diesel fuel.(5) The flotation mechanism of low-grade slime shows that theoxygen-containing functional groups on the surface of low-grade slime are covered especially with C-O functional group(hydroxyl group, ether group) combined by hydrogen bond,because of the function of the PIT microemulsion collector. The contact angle increased from 46.28° to 55.32 °, which indicates that the hydrophobicity of the slime surface was significantly enhanced, and the floatability of the low order slime was effectively improved. |
PDF Full Text Request