| 摘要 |
A process is provided herein for making absorptive pellets from clay "fines" having open pore spaces therein, the fines including clay particles that will pass through a 30-50 mesh screen. The process includes the steps of (a) mixing the clay "fines" in a mixing apparatus with an aqueous solution of lignin; then (b) transferring the moistened clay-lignin particles from the mixing apparatus to a disc pelletizer having a screw conveyor to feed the moistened clay-lignin particles to a die, the die including a die stiffener ring, a roll assembly, an adjustable feed plow and a rapid pelletizing cartridge; and finally (c) forcing the moistened clay-lignin particles through the die to compact and to form the clay-lignin particles into a coherent mass of material and cutting that coherent mass from the die to form the material into pellets, the forcing through the disc pelletizer being under selected conditions of shear substantially simultaneously to compact the clay-lignin particles into the coherent mass and to flash-off excess moisture to provide pellets having a maximum of about 5% by weight moisture and so that a subsequent drying step is therefore unnecessary. The pellets so formed may be used as cat box litter, since they are absorptive pellets having an absorption capacity in the open pore spaces approaching the capacity of the clay "fines" starting material, i.e. about 90-95% of the pore volume of the clay fines. It is believed that the lignin expands during the drying process to improve the pore volume of the pellets.
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