Separation Science and Technology, Vol.33, No.10, 1467-1485, 1998
Dewatering fine coal slurries by gel extraction
Gel extraction is evaluated as a novel technique for dewatering fine coal slurries. This technique uses temperature-responsive gels to absorb water from slurries at low temperatures; after separation of the swollen gel from the dewatered slurry, the gel is heated slightly above ambient temperature, which causes it to release the water it absorbed. The gel can then be recycled. The equilibrium and kinetic properties of poly(N-isopropylacrylamide) gel were evaluated for utility in this process. The gels effectively dewatered slurries to around 70 wt% solids; performance was not a strong function of particle size, though coarser slurries (- 16 mesh) could be dewatered to greater extents than the finer slurries (325 x 400 mesh). The gels showed no sign of deterioration over a period of 2 months and 20 cycles.