Abstract: The invention relates to a method of recovering precious metals from oxidic or refractory or semi-refractory ore material containing precious metal. This recovery of precious metal takes place with optimal comminution work and with more efficient and more reliable leaching also of non-oxidic ore material in such a way that the ore material is subjected to material bed comminution in the grinding gap between two rollers which are pressed against one another under high pressure and revolve in opposite directions and afterwards the comminuted ore material is preferably leached using a stirring movement in a container.

Abstract: Low optical density magnetic fluid which is a stable dispersion of fine magnetic particles. A method of forming the stable dispersion which includes providing an ion exchange resin, loading the ion exchange resin with an ion capable of forming a magnetic phase, treating the loaded resin to form magnetic particles and micronizing the resin and magnetic particles in a fluid to form an aqueous stable colloid. The invention provides submicron particles and submicron particles which are dispersed in an aqueous colloid. A method of forming the stable dispersion which includes providing an ion exchange resin, loading the ion exchange resin with an ion, treating the loaded resin to form nanoscale particles. Fluidizing the resin and particles to form an aqueous stable colloid. A method of forming magnetic materials having tunable magnetic properties and the magnetic materials formed thereby.

Abstract: The invention provides submicron particles. The invention further provides submicron particles which are dispersed in an aqueous colloid. The invention further provides a method of forming the stable dispersion which includes providing an ion exchange resin, loading the ion exchange resin with an ion, treating the loaded resin to form nanoscale particles. The invention further provides fluidizing the resin and particles to form an aqueous stable colloid.

Abstract: Ground calcium carbonate is prepared by a process of grinding a suspension containing calcium carbonate to be ground and a water-soluble grinding agent in an aqueous medium while the temperature of the aqueous suspension is kept at below 60.degree. C.

Abstract: Molecular sieve compositions are prepared by extracting aluminum and substituting chromium and/or tin for extracted aluminum to give molecular sieve products containing framework chromium and/or tin atoms. The process of preparing the chromium and/or tin-containing molecular sieves involves contacting a starting molecular sieve with a solution or slurry of at least one of a fluoro salt of chromium or a fluoro salt of tin under effective process conditions to provide for aluminum extraction and substitution of chromium and/or tin.

Abstract: The invention provides submicron particles. The invention further provides submicron particles which are dispersed in an aqueous colloid. The invention further provides a method of forming the stable dispersion which includes providing an ion exchange resin, loading the ion exchange resin with an ion, treating the loaded resin to form nanoscale particles. The invention further provides fluidizing the resin and particles to form an aqueous stable colloid.

Abstract: An improved process for preparing crystalline mixed metal oxides, such as barium titanate, in which an organometallic compound is reacted simultaneously and continuously with a solution of a divalent metal ion in an alkaline high turbulence energy environment, the reaction product is crystallized, and the crystals are isolated and may be calcined.

Abstract: Ground calcium carbonate is prepared by a process of grinding a suspension containing calcium carbonate and a water-soluble grinding agent in an aqueous medium while the temperature of the aqueous suspension is kept at or below 60.degree. C.

Abstract: An improved flatting agent comprising an inorganic hydrogel having a pore volume of at least 1.0 ml/g, an average particle size in the range 1 to 10 microns, and a particle size distribution such thatt when the flatting agent is dispersed in a coating, the fineness of grind is at least 4.75 on the Hegman scale. The inorganic hydrogel flatting agents of this invention are prepared by milling an inorganic hydrogel under controlled temperature conditions wherein a volatiles content of at least 40 weight percnet is maintained, to produce inorganic hydrogel particles characterized by a pore volume of at least 1.0 ml/g, an average particle size in the range of 1 to 10 microns, and a particle size distribution such that when the flatting agent is dispersed in a coating, the fineness of grind is at least 4.75 on the Hegman scale.

Abstract: Conventional presintering and reaction presintering processes for the production of ceramic powders yield products exhibiting an undesired primary particle size distribution along with localized distribution of impurities, which give rise to the formulation of undesired duplex structures during final sintering.In order to avoid formation of undesired duplex structures within sintered ceramic parts a process and a device for producing ceramic powders based on single- or multi-phase metal oxides (including SiO.sub.2 - compounds), exhibiting a narrow particle size distribution, i.e. with a maximum deviation of the primary crystal size (REM) of +/- 0.75 .mu.m, preferentially less than +/- 0.25 .mu.m, within an average particle size of 0.05 up to 10.0 .mu.m, is conceived. The raw feed material exhibits a specific surface area of 0.05 up to 500 m.sup.2 /g (BET), preferentially 5.0 up to 50 m.sup.

Abstract: The invention relates to a method and apparatus for extracting gold from gold ore. The apparatus and process save capital and operating costs in the extracting of gold from gold ore and include comminution and leaching of the ore, and more particularly the apparatus and process reduce the costs for the ore grinding, and make a fine ore grinding superfluous without having to accept a reduction in the gold yield during leaching. The gold ore is subjected to a product bed stressing and interparticle crushing in the nip of a high-pressure roller press before being leached and the product that has been product-bed-comminuted and subjected to interparticle crushing and the product agglomerates thereby formed are piled on a heap that is sprayed with a lixivium.

Abstract: Mineral values, particularly uranium, are recovered from ground mineral-containing ore by contacting the ground ore with an oxidizing gas and leaching with an acidic or alkaline leach solution. The oxidizing gas treatment significantly increases minerals recovery and/or significantly reduces the severity of the conditions required, particularly the temperature and the concentration of leach chemicals. Further improvements are attained by separating a total ore into a coarse fraction and a fines fraction and separately treating at least a part of these two fractions. The sequence of operations, i.e., treating with oxidizing gas and leaching, the manner of leaching and the conditions of leaching are varied to obtain significantly improved results, based on the discoveries that a coarse fraction is substantially easier to leach than the total ore or the fines fraction and treatment with an oxidizing gas significantly improves the ease of leaching, particularly of the fines fraction.

Abstract: Process of calcining the ball milling manganese zinc MnZn, ferrite material for achieving a ferrite having a ferrous iron content appropriate for optimum magnetic properties. A first initial ball milling step is very carefully controlled as a small amount of metallic iron is blended into an initial mixture which is a catalyst for the ferrous iron reduction reaction during a calcine step. This provides for a predetermined ferrous iron content to be set in the powder prior to any forming or firing steps. The process includes a controlled atmosphere, time, and temperature for the calcining process step, and a second controlled ball milling step over time where the interaction of the stainless steel balls and milled slurry contributes to final ferrous iron content. These two process steps are balanced yielding a MnZn ferrite powder of a predetermined particle size with a controlled ferrous iron content which is a function of both the calcining and ball milling steps.

Abstract: A molded catalyst for fitting into a reactor vessel having an inlet and an outlet for a reactant gas, the catalyst having openings therethrough parallel to the direction of a reactant gas which is introduced into the reactor vessel from the inlet, the catalyst comprising: a wear-resistant front surface facing the inlet of the reactor vessel and a continuation of the front surface extending therefrom, the both being the front portion of the catalyst, and the remaining part of the catalyst made so wear-susceptible as to have either:(a) a wearability of 2-10% in a shaking abrasion test wherein grinding particles having an average particle size of 100 .mu.m and a Mohs scale of 9 are placed in the openings of the catalyst in an amount of 50% by volume based on the total volume of the openings, and the catalyst is shaked for three hours with an amplitude of 77 mm and a frequency of 320 per minute; or(b) a wearability of 7.

Abstract: Mineral values, particularly uranium, are recovered from mineral containing ore by separating the ore into a coarse fraction and a fines fraction, adding a diluent solid material, such as a portion of barren coarse fraction to the fines fraction and leaching the thus diluted fines fraction with a leach solution. The coarse fraction is separately leached, preferably under mild conditions of temperature and leach solution concentration. In another aspect, the total ore is leached, preferably under mild conditions, the thus leached ore is separated into a coarse fraction and a fines fraction, the fines fraction is again leached and at least a part of the leached fines fraction from the second leach step is recycled to the first leach step.

Abstract: The process for the manufacture of special aluminas from the powder produced in the calcination of alumina hydrate, as proposed by the invention, achieves the recovery of this by-product, treating it separatedly from the rest of the alumina, in order to convert it into special alumina of high calcination degree, or alpha alumina, being adequate for uses other than aluminum production. The process is carried out by submitting the by-product to a water-washing stage that reduces its sodium content, solid and liquid separation, filtering and drying. A drying operation is finally carried out with a calcination at a high temperature wherein the alumina of high calcination degree is transformed into alpha alumina.

Abstract: A method for forming a uniform distribution of a substance in calcium hydroxide to obtain pulverulent preparations. The substances are those particularly in a fluid stage such as a solvent, emulsion or suspension.

Abstract: Zinc, copper and cadmium are recovered from their ferrites by subjecting the ferrites to a sulfuric acid bearing solution in the presence of potassium, sodium or ammonium ions under atmospheric conditions at 80.degree.-105.degree. C. to precipitate the iron present in the ferrites as jarosite, separating at least a portion of the jarosite-bearing solid material from the solution before recycling the solution to a neutral leach, from which a copper and cadmium bearing solution is recovered and to which acid and calcine are also fed, feeding the solid obtained from the neutral leach to the said ferrite treatment stage classifying the solid obtained from the neutral leach into a finer and coarser fraction, feeding the finer fraction to the ferrite treatment stage, comminuting the coarser fraction by grinding, leaching or milling and recycling the comminuted fraction to the process.

Abstract: A process for forming uniform distributions of at least one substance in a solid. The process comprises forming a predistribution of the at least one substance in at least one compound, e.g., mixing the at least one substance so that it is distributed throughout the at least one compound, and reacting the at least one compound with water to form a hydroxide, which hydroxide has a larger surface area than the at least one compound. Predistribution must take place before a substantial portion of the compound reacts to form the hydroxide. This process can be used to form a dry powder having at least one substance uniformly distributed therein.

Abstract: The gas stream obtained from the pyrolysis of solid organic wastes and containing halogens, particularly chlorine in the form of the corresponding hydrogen halide is processed to obtain a halide free pyrolytic oil. The gas stream after solids removal is contacted with a solid metal halide acceptor above the dew point of pyrolyzate to form the corresponding metal halide which may be discarded. As an alternative the metal halide can be treated to release the hydrogen halide which is recovered as an acid and the acceptor regenerated for recycle. The preferred acceptor is calcium carbonate.

Abstract: There is provided a method for simultaneously carrying out pulverization of ores and their leaching or extraction within a vertical abrasion mill.

Abstract: Recovery of high purity aluminum chloride is achieved by use of a series of condensers wherein the first condenser is operated at a high temperature of 80.degree.-110.degree. C to insure minimum condensation of other metal chlorides such as titanium chloride, silicon chloride, or the like, while a second condenser operates at a much lower temperature of from 20.degree.-50.degree. C to trap all impurities while reducing the chloride losses to a minimum. The product of the first condenser may then be used as a feed for the electrolytic reduction of aluminum chloride to metallic aluminum.