Abstract: An abrasive includes an alumina-based fiber bound by a matrix resin which contains diamond abrasive grains therein, and a diamond abrasive grain layer provided on the surface of the bound fiber. The abrasive is formed into, for example, a flat plate having a thickness in a range of 0.45 to 1.2 mm, and the diamond abrasive grain layer is provided on at least any one of opposite surfaces of the bound fiber. Flat filaments having a ratio of a long axis to a short axis of the cross-sectional shape thereof in a range of 1.3 to 1.8 are used for the alumina-based fiber.

Abstract: A flocculant composition includes an aqueous solution of a mixture of titanyl sulfate or titanium tetrachloride with a water-soluble, neutral alkali or alkaline earth metal salt at a titanium to alkali or alkaline earth metal salt ratio calculated as TiO.sub.2 of from 0.25:1 to 0.0002:1 by weight. The flocculant composition may further contain a water soluble iron salt at a titanium to iron ratio calculated as TiO.sub.2 and Fe.sub.2 O.sub.3 of from 1:1 to 40:1 by weight, or a water-soluble zirconium salt at a titanium to zirconium ratio calculated as TiO.sub.2 and ZrO.sub.2 of from 1:1 to 40:1 by weight, or a water soluble aluminum salt at a titanium to aluminum ratio calculated as TiO.sub.2 and Al.sub.2 O.sub.3 of from 1:1 to 40:1 by weight.