The application provides a method for heavy floatation and combined separation of collophanite by a multi-grain product spiral chute, wherein the collophanite is first ground and slurried, then subjected to
gravity separation and grading, and the product is divided into coarse-grain product, medium-grain product and fine-grain product; the medium-grain product is returned to continue
grinding, and the coarse-grain product and the fine-grain product are respectively subjected to
reverse flotation treatment. The application adds a medium-grain product to the common double-product
gravity separation process, and the product is mostly un-dissociated
dolomite. Since the physical difference in
specific gravity between the
apatite and the
dolomite in the collophanite is small, the coarse-grain
dolomite has a great influence on the grade of the coarse-grain product of the
gravity separation, so the application returns the medium-grain product to the
ball mill for secondary dissociation, so that the
mineral processing process is simple, the operation cost is low, the separation effect is improved, the product index of the
phosphate concentrate is optimized, and the rational utilization of the
phosphate rock resources is realized.