Abstract: The chromium (III) carbonate of the present invention exhibits a light blue color in a solid state. This chromium (III) carbonate has an L* value of 50 to 70, an a* value of ?4 to ?2, and a b* value of ?10 to ?7, which are represented by the L*a*b* color system (JIS Z8729). This chromium (III) carbonate is preferably completely dissolved within 30 minutes when the chromium (III) carbonate is added, in an amount corresponding to a Cr content of 1 g, to 1 liter of an aqueous solution of hydrochloric acid having a pH of 0.2 at a temperature of 25° C. This chromium (III) carbonate is preferably obtained by contacting an aqueous solution of carbonate and an aqueous solution containing trivalent chromium at a pH of 6 to 12 under the condition of a reaction liquid temperature of 0° C. or more and less than 50° C. Also, preferably, after production of the chromium (III) carbonate, filtration is performed, and the chromium (III) carbonate is washed with water until the conductivity of the filtrate is 5 mS/cm or less.

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3-3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3?3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: The chromium (III) carbonate of the present invention exhibits a light blue color in a solid state. This chromium (III) carbonate has an L* value of 50 to 70, an a* value of ?4 to ?2, and a b* value of ?10 to ?7, which are represented by the L*a*b* color system (JIS Z8729). This chromium (III) carbonate is preferably completely dissolved within 30 minutes when the chromium (III) carbonate is added, in an amount corresponding to a Cr content of 1 g, to 1 liter of an aqueous solution of hydrochloric acid having a pH of 0.2 at a temperature of 25° C. This chromium (III) carbonate is preferably obtained by contacting an aqueous solution of carbonate and an aqueous solution containing trivalent chromium at a pH of 6 to 12 under the condition of a reaction liquid temperature of 0° C. or more and less than 50° C. Also, preferably, after production of the chromium (III) carbonate, filtration is performed, and the chromium (III) carbonate is washed with water until the conductivity of the filtrate is 5 mS/cm or less.

Abstract: In a method for manufacturing chromium hydroxide according to the present invention, chromium hydroxide having higher solubility in an acidic aqueous solution than chromium hydroxide obtained by conventional manufacturing methods can be obtained. The method is characterized by simultaneously adding an aqueous solution of an inorganic alkali and an aqueous solution containing trivalent chromium to an aqueous medium under the condition of a reaction liquid temperature of 0° C. or more and less than 50° C. to produce chromium hydroxide. The pH of the reaction liquid while the aqueous solution containing trivalent chromium and the aqueous solution of the inorganic alkali are added is preferably maintained in the range of 7.0 to 12.

Abstract: It is intended to provide a chromium (III)-containing aqueous solution which has widely adjustable molar ratios of various acid radicals to Cr and is useful as a source of trivalent chromium or a supplementary source of trivalent chromium for the bath in the surface treatment of various metals. Specifically, the chromium (III)-containing aqueous solution is characterized by containing a complex chromium (III) salt which is produced by performing chromic acid reduction reaction in the simultaneous or sequential presence of two or more acids selected from an inorganic acid other than chromic acid and an organic acid.

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3-3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3-3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: An aqueous solution containing an organic acid chromium (III) salt represented by general formula: Crm(Ax)n, wherein A represents a residue left after proton removal from an organic acid; x represents a charge of A; and m and n represent integers satisfying equation 3m+xn=0, is disclosed. The aqueous solution contains the organic acid chromium (III) salt in a concentration of 6% by weight or higher in terms of Crm(Ax)n, has impurity ion concentrations of Na?30 ppm, Fe?20 ppm, Cl?0.001%, SO4?0.03%, and NO3?20 ppm per 20 wt % concentration of Crm(Ax)n, and is substantially free from chromium (VI).

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3?3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: The present invention provides silicic acid hydrate having a large pore volume and tiny particle diameters, and a process for preparing it. There is disclosed silicic acid hydrate obtained by neutralizing an aqueous solution of sodium silicate with a mineral acid, which has particle properties represented by an oil absorption of 250 to 350 ml/100 g, a total pore volume of 4.0 to 6.0 cc/g, an average pore radius of 200 to 400 .ANG., and an average pore diameter of 3.0 to 15 .mu.m by the laser method, or 2.0 to 4.0 .mu.m by the coulter method, or 0.5 to 3.5 .mu.m by the centrifugal precipitation method.