Compound Polar Collector In Low Rank Coal Flotation

The resources of low rank coal are abundant in China,the rational and efficient utilization of low rank coal is of great significance to alleviate the increasingly tense energy pressure,reduce energy consumption and protect the environment in China.However,due to the poor hydrophobicity of the low rank coal with the oxygen functional groups on surface,the high surface roughness and more crack pores,it is difficult achieve with the common coal flotation collectors like kerosene,fuel oil or diesel oil(oily collector).For higher-rank coals,the reagent consumption in flotation is low because of the natural hydrophobicity of the coal.However,the oxidized coals or low rank coals are difficult to float with commonly used fuel oil or kerosene and large amounts of collectors are required to achieve satisfactory yields.Inner Mongolia Erdos long-flame coal were selected in this paper to research the mechanism between collectors and coals,compound agent of polar reagents with different carbon chain length and kerosene are used as collectors to study the effect of different carbon chain length on the flotation collectivity and selectivity.The ash content of coal slime used in this study is 15.12% approximately and the domain particle size is-0.045 mm with the yield of 65.11% and the ash content of 20.67%.And the main gangue minerals in coal sample are quartz,kaolin and a few of clinochlore.On the other hand,there are a large amount of oxygen-containing functional groups such as C-O,C=O and O=C-O on coal surface,and the contact angle of coal sample is as low as 46.01°.In conclusion,low rank coals have poor flotability.The results of different carbon chains length coumpound with amines and acids show that it can get a better flotation results in the presence of the amines with different carbon chains length,the best flotation complete index is 25.02%.However,and carboxylic acid compounds have better collectivity only when short carbon chain,the best flotation complete index is 25.38%.When the carbon chain of carboxylic compound collectors is more than 12,the collectivity is poor and the recovery of the combustibles coal decreases obviously,and it is far lower than that of the compound amine reagents with the same carbon chain length.The flotation collectivity and selectivity of compound agents are better than the kerosene.There are different interaction between the same kind polar agent with different carbon chain length.And there are also different inteaction between the same carbon chain length agent with different polar functional groups.so polar mixed agents and low rank coal have different action modes.There are three main interactions between the short chain amine compound reagents between coal: hydrogen bonding,electrostatic interaction and hydrophobic interaction.The interaction between long chain amine compound agent and coal surface involved mainly two ways: hydrogen bonding,and hydrophobic interaction.The interaction between short chain carboxylic compound agent and coal surface involved mainly two ways: hydrogen bonding,and hydrophobic interaction.There are only one main interaction between the long chain carboxylic compound agent between coal: hydrophobic action.At the same time,the hydrogen bonding of carboxylic acids is stronger than that of amine compounds.Electrostatic interaction can significantly improve the collectivity,and hydrogen bonding can improve the selectivity.