Flotation intensification of low-rank coal using a new collector prepared by composition and following plasma

Flotation reagents have a significant impact on the flotation of low-rank coal. In recent years, more research had been conducted on the low-rank coal flotation using chemically modified hydrocarbon oil as collector. With regard to its fast modified rate, environmental compatibility and high efficiency, the plasma modification is considered as a promising treatment technology for the production methods of low-rank coal collector. Previous research shows that the collectors modified by plasma using traditional single non-polar oil as raw material cannot reduce the amount of regent. In this study, a new collector modified by plasma using traditional fossil oil and secondary octyl alcohol as raw materials was used to enhance low-rank coal flotation. The chemical structure of new collector, adsorption mechanism, flotation performance of coal and collector were investigated through the flotation test, GC-MS, XPS, FTIR and quantum chemistry calculation. Under the optimal formulation conditions of 80% of dodecane and 20% of sec-octyl alcohol, 10 min of plasma treatment, and 2.5 kg/t of new collector consumption, the flotation results show that the yield of clean coal and the combustible body recovery rate are 55.32% and 64.81%, respectively. The clean coal yield is 15 percentage points higher than the clean coal yield before treatment, and the dosage of reagent is reduced by more than 50%. Through mixing and following plasma treatment, the dodecane and sec-octyl alcohol are translated to the mixture which contains dodecane, sec-octyl alcohol, dodecanol, dodecanone and long chain oxygenated organic compounds. The adsorption energy between long chain oxygenated organic compounds which are easier to interact with the oxygen-bearing functional and the surface of low-rank coal is above 54 kJ/mol. The hydrophobicity and floatability of low-rank coal are improved through above adsorption. The C-C/C-H functional on coal slime surface is 7.41 percentage points higher than that on raw coal, the O groups content on coal slime surface is 2.61 percentage points lower than that on raw coal.