Abstract: A filter for reducing heavy metals in water employs particulate boneblack (bone char) material as a filtration agent. A layer of boneblack (bone char) impregnated filter material and a layer of fibrous substrate are helically interwound around a hollow, porous central core to form the cartridge elements of a filter cartridge designed to reduce heavy metal concentrations in drinking water. A porous outer cage encloses the helically wound layers, and end caps are bonded to the cartridge elements at each end thereof. Methods of using boneblack particles to reduce heavy metal concentrations in water are also disclosed.

Abstract: A composition useful as a pigment is disclosed, the composition comprised of a particulate filler material such as silica, with the individual particles being coated with elemental carbon in the form of fine particles such as those contained in carbon black. The composition is produced by a mechanical processing of a dry mixture of the particulate material and the carbon black of proportions of up to approximately 50% by weight of carbon black and 50% or more of silica of a 50 to 100 micron particle size range. The mixture is processed in a ball mill to reduce the particle size of the particulate material to an average 10 micron size, the particles at the same time being coated by deposition of the carbon black particles so as to adhere tightly to the surface thereof. An air flotation separation process sorts the resulting coated particles into various size ranges suitable for particular applications.