A method of making an alumina including providing an alumina slurry, aging the slurry, adding a tricarboxylic acid to the aged alumina slurry, further aging the slurry, and spray drying, the method being characterized by the addition of a dicarboxylic acid either at the same time as the tricarboxylic acid, or after the second aging and before the spray drying. The resulting alumina is dispersible at a pH greater than 9.5 above 95% and has a viscosity below 0.4 Pa.Math.S for 10 wt % sols.

The purpose of the present disclosure is to provide a composition for a second battery porous membrane having an excellent redispersibility. The disclosed composition for a second battery porous membrane contains -alumina-based modified particles, a particulate binder and water, and each -alumina-based modified particle has a peak in a region from 3500 cm.sup.1 to 3600 cm.sup.1 in an infrared diffuse reflectance spectrometry.

The present disclosure relates to an alumina having a surface area in the range of 330-400 m.sup.2/g, a pore volume in the range of 1.2-1.7 cc/g, and an average pore diameter in the range of 125-160 . The present disclosure also relates to alumina extrudates having a diameter in the range of 1 mm to 3 mm, a surface area in the range of 300-360 m.sup.2/g, a pore volume in the range of 0.8-1.3 cc/g and pore diameter in the range of 90-130 with a crushing strength in the range of 1-2.5 daN/mm. Further, the present disclosure relates to a process for the preparation of alumina and alumina extrudates. The alumina extrudates can be used as a support for catalyst preparation or as a catalyst or adsorbent in various processes. The process of the present disclosure enhances metal loading capacity, has better metal dispersion, and exhibit delay in deactivation of the catalyst due to mouth pore plugging.

The purpose of the present disclosure is to provide a composition for a second battery porous membrane having an excellent redispersibility. The disclosed composition for a second battery porous membrane contains -alumina-based modified particles, a particulate binder and water, and each -alumina-based modified particle has a peak in a region from 3500 cm.sup.1 to 3600 cm.sup.1 in an infrared diffuse reflectance spectrometry.

An alumina slurry containing alumina dispersed in a dispersion medium, the alumina having an average primary particle diameter of 0.1 m or more and 1.0 m or less, the alumina satisfying the following condition (1), and the slurry having a content of the alumina of 30% by mass or more and 70% by mass or less and a content of water in the dispersion medium of 50% by mass or more: condition (1): in relationship of a pore diameter r1 () and a pore volume Dv1 (mL/g) of the alumina measured by a nitrogen desorption method based on JIS Z8831-2 (2010), the pore volume Dv1(80) at r1=80 and the maximum value Dv1(M) of Dv1 in a range 20r180 satisfy Dv1(M)>Dv1(80).

Disclosed is an alumina slurry substantially including alpha-alumina particles and water, wherein the alpha-alumina particles satisfy all particle diameter distribution conditions (a) to (d) mentioned below, the alpha-alumina particles have an alumina purity of 90% by weight or more, the content of alumina in the slurry is 20% by weight or more and 50% by weight or less, and the slurry has a viscosity of 0.5 Pa.Math.s or more and 15 Pa.Math.s or less: condition (a): the average particle diameter is 1 m or less, condition (b): particles having a particle diameter of less than 0.2 m account for 7% by weight or less, condition (c): particles having a particle diameter of more than 1.5 m account for 15% by weight or less, and condition (d): one or more frequency maximums exist in a particle diameter range of 0.1 m or more and less than 0.5 m.

The invention relates to a process for manufacturing nanoparticles that are self-dispersing in water. It also relates to the self-dispersing nanoparticles obtained by the process of the invention and also a process for manufacturing a heat-transfer fluid containing the nanoparticles according to the invention or obtained by the process of the invention. The process of the invention comprises the following steps: a) optionally, manufacture of an aqueous dispersion of nanoparticles chosen from the nanoparticles of alumina (Al.sub.2O.sub.3), of zinc oxide (ZnO), of titanium oxide (TiO.sub.2), of silica (SiO.sub.2) and of beryllium oxide (BeO), b) addition to an aqueous dispersion of nanoparticles chosen from nanoparticles of alumina (Al.sub.2O.sub.3), of zinc oxide (ZnO), of titanium oxide (TiO.sub.2), of silica (SiO.sub.2) and of beryllium oxide (BeO), of a water-soluble polymer chosen from polyvinyl alcohols, polyethylene glycols, polyvinylpyrrolidones, polyoxazolines, starches, and mixtures of two or more thereof, and c) thermal quenching of the dispersion obtained in step b), and d) lyophilization of the quenched dispersion obtained in step c). The invention finds an application in the field of coolants in particular.

Described herein are stable aqueous dispersions of alumina and methods of preparing the same.

The present invention relates to a calcined shaped alumina and to a method of preparing a calcined shaped alumina. The method comprises that the alumina in the alumina suspension is hydrothermally aged to have a specific crystallite size. This in turn produces a highly stable alumina in the form of a calcined shaped alumina particularly at temperatures of 1200 C. and above.

The present invention relates to a calcined shaped alumina and to a method of preparing a calcined shaped alumina. The method comprises that the alumina in the alumina suspension is hydrothermally aged to have a specific crystallite size. This in turn produces a highly stable alumina in the form of a calcined shaped alumina particularly at temperatures of 1200 C. and above.