176 results about "Gibbsite" patented technology

An activated alumina formed body with a high bulk density and a large macro-pore volume is provided. The activated alumina formed body can be produced by a method comprising the steps of calcining a gibbsite-phase aluminum hydroxide having a median particle size of from about 10 μm to about 35 μm and a packed bulk density of from about 1.05 g / cm3 to about 1.3 g / cm3 to obtain an at least partially rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water; maintaining the formed body in the presence of water to rehydrate the formed body; and calcining the rehydrated formed body to obtain an activated alumina formed body. The activated alumina formed body is usable as an adsorbent, a catalyst supporting precious metal or the like.

This invention provides a method for extracting Al and iron from a ferric gibbsite, which grinds and dissolves the ferric gibbsite then carries out rough and fine separation-washing to the red mud and sends the refined liquor to the resolving plant to separate AlOH and bake it to get A10. The red mud is matched with recovery coal and burning coal to be dried and baked then to be ground and selected magnetically to get sponge iron power to be filtered and matched with raw material, dried to get sponge iron balls.

A low cost support useful in chemical reactions and automotive arts is formed by rehydrating a flash calcined gibbsite in an aqueous acidic solution. The rehydrated support can be subsequently stabilized by doping with a stabilizing metal such as lanthanum. The alumina support has excellent thermal stability, high sodium tolerance, high activity with low precious metal loading, and high pore volume and surface area.

The invention discloses a composite oxide carrier with bimodal mesopores as well as a preparation method and application of the composite oxide carrier. An oxide carrier is used for an immersion type CO2 methanation catalyst, and comprises a basic carrier gamma-Al2O3 and structure stabilizing additives. A composite oxide carrier comprises a mixture of gamma-Al2O3, pseudo bohemite (Al2O3.H2O) and gibbsite (Al2O3.3H2O). The composite oxide carrier is prepared by adding the structure stabilizing additives such as alkaline-earth metal, transition metal, rare-earth metal and the like, a pore former and a binder in a process including impregnation, mixing, granulation, forming and calcination. The composite oxide carrier provided by the invention has relatively large specific surface area and a bimodal distributed mesoporous structure, and has the advantages of high carrier water absorption rate, stable structure and good mechanical strength; the preparation process facilitates enlarged production. A supported Ni-based CO2 methanation catalyst prepared by adopting the carrier disclosed by the invention has relatively good low-temperature catalysis activity and long-time operation stability.

The invention discloses a method for treating gibbsite by using high-concentration alkali liquor under normal pressure. The method comprises the following steps of: stirring and uniformly mixing a high-concentration NaOH solution and high-iron gibbsite in an alkali-resistant reactor, heating to the temperature of between 110 and 140 DEG C under normal pressure, and performing primary separation on digestion slurry by using a magnetic separation grader; leaching the obtained solid slag at the temperature of 65 DEG C by using a small amount of water, and performing further liquid-solid separation to obtain high-iron red mud; performing cooling crystallization on a solution obtained after magnetic separation, returning a mother solution to the digestion process, adding a sodium aluminate crystal into a seed decomposition mother solution, redissolving to obtain a sodium aluminate solution, adding Bayer process red mud, lime and the like into the sodium aluminate solution, and performing desilication twice to obtain a sodium aluminate fine solution with the aluminum-to-silicon ratio of 145 to 180 and the molar ratio alphaK of sodium oxide to aluminum oxide of 1.45 to 1.55; and decomposing the fine solution by a Bayer process under the conventional conditions, and performing liquid-solid separation to obtain aluminum hydroxide particles and the seed decomposition mother solution. The seed decomposition mother solution is not evaporated and is returned to the process after aluminum salt and coarse hydrogen and aluminum are dissolved in the seed decomposition mother solution, so that the defect of large water evaporation amount caused by a large concentration difference is overcome.

The invention relates to a catalyst carrier used for generating gas pulse in a reactor. The outer shape of the catalyst carrier is in a circular cake shape (flying saucer shape). The catalyst carrier is composed of a plurality of unit holes. The structure of each unit hole is that two ends of unit hole are prismoids and the middle portion of the unit hole is a hollow neck (weir groove), wherein the prismoids are preferably triple prismoids, quadruple prismoids or pentagonal prismoids, hexagonal prismoids, regular circular truncated cones, etc. The catalyst carrier is made of chemical ceramic materials. The chemical ceramic materials comprise the following raw materials of, by weight, gibbsite, 25-35 parts of kaolin, 10-20 parts of Guizhou soil, 5-10 parts of talcum, 8-12 parts of feldspar and 8-12 parts of alkali metal oxide. The catalyst carrier is suitable for being used as a carrier for the catalyst of the field of petroleum chemistry or as filling materials in the reactor. The carrier with the structure enhances a mass transfer effect and a heat transfer effect between gas and liquid, and further increases catalytic effect of the catalyst and reaction rate. The catalyst carrier has high hardness, high strength, large specific surface area, good high temperature resistance and good acid and alkali resistance.

The invention provides a preparation method of pseudo-boehmite. The preparation method, which comprises a gel formation reaction which is carried out on a sodium aluminate solution and an acidic gas, is characterized in that: the acidic gas is a mixed gas containing CO2 and at least one gas with the pressure of less than 6.38kPa; the gel formation reaction temperature is 10-100DEG C; and the amount of the acidic gas and the ratio of CO2 to the gas with the pressure of less than 6.38kPa in the acidic gas make the pH value of the gel formation reaction be 3-7. Compared with the prior art, the method provided by the invention, which ensures that contents of gibbsite and dawsonite in the obtained pseudo-boehmite are zero or very small, allows the synthetic reaction of pseudo-boehmite to be convenient to operate.

Disclosed is a prepreg obtained by impregnating a woven fabric base with a thermosetting resin composition, wherein the thermosetting resin composition contains 80 to 200 volume parts of an inorganic filler per 100 volume parts of a thermosetting resin, and the inorganic filler contains (A) gibbsite aluminum hydroxide particles having an average particle diameter (D50) of 2 to 15 μm, (B) at least one inorganic component selected from the group consisting of boehmite particles having an average particle diameter (D50) of 2 to 15 μm and inorganic particles that have an average particle diameter (D50) of 2 to 15 μm and that contain crystal water having a release initiation temperature of 400° C. or higher or contain no crystal water, and (C) aluminum oxide particles having an average particle diameter (D50) of 1.5 μm or smaller, the compounded ratio (volume ratio) of the gibbsite aluminum hydroxide particles (A), the at least one inorganic component (B) selected from the group consisting of the boehmite particles and the inorganic particles, and the aluminum oxide particles (C) being 1:0.1 to 2.5:0.1 to 1.

Provided is an aluminum hydroxide powder used as a resin filler having excellent resin filling properties. Also provided is a method for producing the same. The aluminum hydroxide powder used as a resin filler has a gibbsite crystal structure; the average grain diameter in the grain diameter distribution as determined by laser scattering is between 2.0 and 4.0 [mu]m; the ratio D90 / D10 of secondary grain diameter D10, which is the diameter of 10% of the cumulative mass from the microparticle portion, and the secondary grain diameter D90, which is the diameter of 90% of the cumulative mass from the microparticle portion, is between 4.0 and 6.0; D2 and D1 satisfy formula (1) 2xD1 = D2 = 4xD1 (1) when there are two or more frequency maximums within a grain diameter range I that is between 0.5 and 5.0 [mu]m, with D2 being the maximum grain diameter of the frequency maximum having the largest maximum grain diameter of the frequency maximums within the grain diameter range I and D1 being the maximum grain diameter of the frequency maximum showing the smallest maximum grain diameter; the intensity ratio I (110) / I (002) of the peak at crystal faces (110) and (002) as determined by powder X-ray diffraction is between 0.30 and 0.45; and the total sodium content is 0.10 wt% or less in terms of Na2O.

The invention discloses a preparation method of high heat-resistant boehmite. The method comprises the following steps: firstly converting aluminium hydroxide with the crystalline structure of gibbsite to boehmite under the condition that the temperature is not less than 350 DEG C and the pressure is not less than 10kPa; secondly grinding boehmite to 50-400nm (particle size), then dispersing boehmite particles evenly in water, adopting wet high-speed mixing method to disperse boehmite, performing surface nano-SiO2 coating; and finally removing impurities, purifying, and drying to obtain the boehmite product. Boehmite which is prepared by the dry heat method adopted by the invention has low content of impurities, the boehmite conversion rate is high, and the grain size is controllable. In addition, the invention uses the inorganic modifier, thus significantly reducing oil adsorption of material, increasing liquidity and broadening the application of boehmite in the field of electronic materials.