The invention discloses a method for crystal seed precipitation of a sodium aluminate solution, comprising the following steps of: 1), mixing a sodium aluminate solution with Al(OH)3 crystal seeds, starting to stir and precipitate at 60 DEG C to 80 DEG C, wherein the causticity ratio of the sodium aluminate solution is 1.25 to 1.60 and the crystal seed coefficient is 1.0 to 4.0; 2), cooling the precipitation system to 40-50 DEG C; and 3), continuously heating the precipitation system within 5 hours to 20 hours, wherein the heating amplitude is 5 DEG C to 25 DEG C, and the final temperature is not higher than 65 DEG C. By adoption of the method provided in the invention, the crystal seed precipitation process of the sodium aluminate solution is effectively reinforced, and the technical and economical indexes of yield in the precipitation, cycle efficiency of aluminium oxide production, and the like are improved.

Method for crystal seed precipitation of sodium aluminate solution

The present invention addresses the problem of providing a method for producing vanadium dioxide-containing particles having excellent thermochromic performance and transparency. This method for producing vanadium dioxide-containing particles is a method for producing, using hydrothermal reaction, vanadium dioxide-containing particles having thermochromic performance, wherein the method is characterized in that the vanadium dioxide-containing particle surface is surface modified without causing separation of a solvent and the vanadium dioxide-containing particles.

Method for producing vanadium dioxide-containing particle and dispersion

The invention discloses a surface-modified aluminum hydroxide and a preparation method thereof. The surface-modified aluminum hydroxide comprises, by mass, 30 parts of aluminum hydroxide and 0.3-1.2 parts of a modifier. The modifier is Span, a complex of Span and stearic acid, or a complex of Span and sodium stearate. The Span is Span 40, Span 60 or Span 85. The preparation method comprises the following steps of preparing an aluminum hydroxide aqueous suspension having a mass concentration of 10%, heating the aluminum hydroxide aqueous suspension to a temperature of 80-85 DEG C, preparing a modifier-ethanol solution having a modifier mass concentration of 1%, adding the modifier-ethanol solution into the aluminum hydroxide aqueous suspension, heating the mixed suspension to a temperature of 70-90 DEG C, keeping the temperature for 0.5-1.5h, and carrying out standing, suction filtration, washing, drying and grinding so that the surface-modified aluminum hydroxide which is conducive to uniform dispersion in a polymer base and improves base compatibility is obtained.

Modified aluminum hydroxide and preparation method thereof

The invention discloses a process for removing an organic matter, iron and silicon dioxide in a sodium aluminate solution. The process comprises the following steps: heating sodium aluminate circulating mother liquor to 80 to 90 DEG C, adding calcium oxide into the sodium aluminate circulating mother liquor for adsorption displacement reaction, the calcium oxide being obtained by calcining or precipitating pure limestones and calcining and crushing obtained calcium carbonate, performing stirring in an open state after addition to separate out the organic matter sodium humate in the solution in form of calcium salt, simultaneously reacting the calcium oxide with sodium aluminate in the solution to generate fine calcium aluminate particles with large surface areas, performing solid-liquid separation after reaction, filtering and separating small particles suspended in the solution after reaction, regulating the temperature of the solution to 45 to 55 DEG C, and adding 3 to 6 volume percent of hydrogen peroxide to further decolorize the solution, the treated mother liquor being used for preparing refined liquor. An operating flow is simple, no additional equipment is required, and the process is high in organic matter removal efficiency and low in cost, and has good impurity removal and decolorization effects and a broad application prospect.

Process for removing organic matter, iron and silicon dioxide in sodium aluminate solution

The invention discloses a technology for producing superfine aluminum hydroxide through a two-section method. The method comprises the following steps: (1) preparing seed pulp; (2) adding the seed pulp into a sodium aluminate solution with the temperature of 50 to 55 DEG C; controlling the ratio of the seed pulp and the sodium aluminate refined solution according to the ratio ranging from (1 to 5)to (1 to 10); when white fine grains are produced, decomposing all the white fine grains into aluminum hydroxide grains with the size of 0.1 to 0.3 micron; when external conditions of the grains arethe same, growing for 1 to 6h until the size is 0.4 to 0.6 micron and the decomposition rate reaches 40 to 50 percent; (3) adding superfine aluminum hydroxide seeds produced by one section into the sodium aluminate solution with the temperature of 55 to 60 DEG C, wherein the ratio of the added sodium aluminate refined solution and a refined solution added in the first section ranges from (1 to 20)to (1 to 25), the causticity ratio of the refined solution is 1.4 to 1.6, and the decomposition rate reaches 40 to 60 percent and the granularity of the aluminum hydroxide reaches 1.5 to 2.0 micronsafter 18 to 30h. The invention provides the technology for producing the superfine aluminum hydroxide through the two-section method, which has the advantages of controllable method, stable product quality, high rate of finished products and cost saving.

Li Wucheng

Papers

Method for preparing high-whiteness aluminium hydroxide micropowder from Bayer process sodium aluminate solution

Technology for coproducing mercaptoacetic acid and dichloroacetic acid by utilization of chloroacetic acid mother liquor and device thereof