Disclosed herein are system and methods to effectively leach coal ash with hydrochloric acid and separate an insoluble silica product and then selectively precipitate, from the leachate, a number to value-added, strategic, marketable products using a hydroxide reagent. The resulting precipitated products include iron, aluminum, magnesium, calcium, and a mixture of rare earth elements and transition metals. These can be separated as hydroxides or converted to oxides or carbonates. Using hydrochloric acid for leaching and converting the chloride to sodium chloride in the final step results in practically no waste for this process. The silica can be further purified using sodium hydroxide fusion or caustic leach methods and some minor streams from this process are recycled to minimize any waste stream. These systems and methods can be applied to a number of other industrial waste products such as red mud from the aluminum process, slag from steel furnaces, mine tailings, and other metal-bearing waste streams.

The present invention relates to alumina flakes having a defined thickness and particle size distribution and to their use in varnishes, paints, automotive coatings, printing inks, masterbatches, plastics and cosmetic formulations and as substrate for effect pigments.

The present invention relates to alumina flakes having a defined thickness and particle size distribution and to their use in varnishes, paints, automotive coatings, printing inks, masterbatches, plastics and cosmetic formulations and as substrate for effect pigments.

Various embodiments disclosed relate to an abrasive article (10). The abrasive article (10 includes a backing (12) defining a major surface. The abrasive article (10) includes an abrasive layer including a plurality of tetrahedral abrasive particles (16) attached to the backing (12). The tetrahedral abrasive particles (16) include four faces joined by six edges terminating at four vertices (40, 42, 44, 46). Each one of the four faces contacts three of the four faces, and a major portion of the tetrahedral abrasive particles (16) have at least one of the vertices (40, 42, 44, 46) oriented in substantially a same direction.

A supported catalyst, its method of preparation and use in hydrogenation methods, which catalyst contains an oxide substrate that is for the most part calcined aluminum and an active phase that contains nickel, with the nickel content between 5 and 65% by weight in relation to the total mass of the catalyst, with the active phase not containing a metal from group VIB, the nickel particles having a diameter that is less than or equal to 20 nm, the catalyst having a median mesopore diameter of between 14 nm and 30 nm, a median macropore diameter of between 50 and 200 nm, a mesopore volume that is measured by mercury porosimetry that is greater than or equal to 0.40 mL/g, and a total pore volume that is measured by mercury porosimetry that is greater than or equal to 0.42 mL/g.

Alumina having excellent electrolytic solution stability, a slurry containing the same, an alumina porous film using the same, a laminated separator, a nonaqueous electrolyte secondary battery and a method for manufacturing the nonaqueous electrolyte secondary battery are provided. Alumina is provided including one or more selected from K, Mg, Ca, Sr, Ba and La in the total amount of 200 to 50,000 ppm by mass, wherein a surface concentration of one or more elements is 0.5 to 20 at % in total. Alumina is provided in which in an infrared absorption spectrum of the alumina obtained by Fourier-transform infrared spectroscopy, a peak having an intensity larger than that of a baseline defined by a line segment connecting an intensity at 3,400 cm.sup.1 and an intensity at 3,500 cm.sup.1 and having a half width of 90 cm.sup.1 or less, does not exist in a range of 3,400 to 3,500 cm.sup.1.

Sintering is an important issue in creating crystalline metal oxides with high porosity and surface area, especially in the case of high-temperature materials such as metal aluminates. Herein we report a rationally designed synthesis of metal aluminates that diminishes the surface area loss due to sintering. Metal aluminate (e.g. MeAl.sub.2O.sub.4or MeAlO.sub.3Me=Mg, Mn, Fe, Ni, Co, Cu, La, or Ce; or mixture thereof) supported on -Al.sub.2O.sub.3 with ultralarge mesopores (up to 30 nm) was synthesized through microwave-assisted peptization of boehmite nanoparticles and their self-assembly in the presence of a triblock copolymer (Pluronic P123) and metal nitrates, followed by co-condensation and thermal treatment. The resulting materials showed the surface area up to about 410 m.sup.2.Math.g.sup.1, porosity up to about 2.5 cm.sup.3.Math.g.sup.1, and very good thermal stability. The observed enhancement in their thermomechanical resistance is associated with the faster formation of the metal aluminate phases. The nanometer scale path diffusion and highly defective interface of -alumina facilitate the counter diffusion of Me.sup.X+ and Al.sup.3+ species and further formation of the metal aluminate phase.

A composition having a plurality of abrasive particles including alumina, the plurality of abrasive particles have mesoporosity with an average meso branching index of at least 55 junctions/microns.sup.2 and a median particle size (D50) of at least 5 microns.

A particulate material having a body including a dopant contained in the body, the dopant is non-homogenously distributed throughout the body and the body has a maximum normalized dopant content difference of at least 35%.

An alumina exhibiting a structure with a porosity such that the volume of the pores having a diameter of between 70 and 2000 is between 0.15 and 0.50 ml/g, and comprising at least one alkali metal (M), such that the content by weight of alkali metal, expressed as M.sub.2O, is between 400 and 1500 ppm, with respect to the total weight of the alumina, and a process for the transformation of a feedstock comprising at least one alcohol into an olefinic effluent, said process comprising a stage of dehydration of said alcohol in the presence of the alumina according to the present invention, having an acidity and a structure with a porosity which are optimal.