Study On Magnetic Absorbent Polymer Preparation And Fine Coal Dewatering

At present the fine coal dewatering is one of the technical problems in the coal processing industry.The use of superabsorbent polymer is a brand-new method to achieve the fine coal dewatering by absorbent materials.The dehydration process is controlled easily,but the recovery and regeneration of resin are difficult.In this paper,the preparation of magnetic absorbent polymer has been presented that the resin can be separated from fine coal by magnetic separation after absorbing water and then regenerated by taking advantage of the heat shrinkable properties.Based on the the inverse suspension polymerization to synthetize polyacrylic acid sodium,Fe3O4 powder was added to join the blending reaction in order to prepare the magnetic absorbent polymer.The water absorbency and the water holding capacity were investigated,the thermostability and the ferromagnetic content were determined and the the effects of magnetic media on the resin performances were studied.The experiments of fine coal dewatering were carried out by making use of polyacrylic acid sodium magnetic absorbent polymer afterwards.The effects of some factors on the dewatering and magnetic absorbent polymer on inherent moisture were observed.The relationship between the water absorbency of dehydrating agents and the result of fine coal dewatering was discussed.Then on the basis of the preparation of magnetic absorbent polymer,temperature sensitive magnetic absorbent polymer with interpenetrating network structure was obtained by the two-step method.The water absorbency,the temperature sensitivity and the water holding capacity were investigated,the thermostability and the ferromagnetic content were determined and the the effects of temperature sensitive media on the resin performances were studied.The main results are as follows:(1)The water absorbency and the water holding capacity have a significant change under the condition of different reaction temperature,reaction time,acrylic acid neutralization degree,initiator dosage and crosslinking agent dosage.The water absorbency,the temperature sensitivity and the water holding capacity change obviously under the condition of different reaction temperature,reaction time,monomer ratio,initiator dosage and crosslinking agent dosage as well.(2)Because of the addition of the magnetic media,the water absorbency and the water holding capacity of the magnetic absorbent polymer are greatly reduced compared with nonmagnetic absorbent polymer,but the change of the thermostability is not obvious.And then with the addition of temperature sensitive media,the water absorbency and the thermostability of the temperature sensitive magnetic absorbent polymer have a big fall,yet the water holding capacity have a slight increase.The ferromagnetic content of the ordinary magnetic absorbent polymer is high to a certain degree,which is good for the recovery by magnetic separation.Nevertheless,the temperature sensitive magnetic absorbent polymer is not the case.(3)The moisture content of the fine coal can be reduced below 10%in 10 minutes with 5%resin no matter how much the initial moisture content of the fine coal is.It has the characteristics of high dehydration rate and fine dehydration effect.But for the internal moisture absorption is not obvious.The higher the dehydrant is,the finer the dehydration effect becomes.