Abstract: The invention relates to the production of calcium compounds containing water of crystallization by means of a chemical reaction between an aqueous alkaline sodium aluminate solution and solid or dissolved or suspended calcium (hydr)-oxide in the presence of carbon dioxide or carbonate; and to the use of these compounds. The resulting precipitate is separated by sedimentation, dehydration, drying and/or clacination and/or grinding or suspending the resulting filter cake and reacted with at least one mineral acid and/or at least one salt of the same. The resulting precipitate, which contains water of crystallization, is separated by sedimentation, dehydration, drying and/or grinding.

Abstract: Disclosed herein is a method for producing plasters that contain chloride contents of less than 0.5% by weight from calcium-containing impure products or residues having a high chloride content (e.g., about 10% or higher based on the total product or residue weight). The method does not require the addition of fly ash, SiO.sub.2 or Al.sub.2 O.sub.3. The method comprises temperature and water-mediated conversion of calcium chloride to calcium oxide in the calcium-containing product or residue using water, steam and/or substances that generate water to obtain calcium oxide and hydrochloric acid; and sulfating calcium components in the product or residue using oxygen and sulfur-containing, largely calcium-free substances. The product so obtained is an anhydride plaster which can optionally be hydrated.

Abstract: A process of leaching ores, ore concentrates, intermediate metallurgical products and the like, which contain acid-soluble constituents, by a treatment in an acid aqueous solution under pressure in a tubular reactor. The slurry contains suitably 300 to 1100 g starting material per liter of water and a velocity of flow of 0.5 to 4.0 m/sec. is suitably maintained throughout the flow path in the tubular reactor of the slurry and of the leached suspension.

Abstract: Gold and/or silver is leached from comminuted ore with an alkaline cyanide lixiviant at a superatmospheric pressure of at least 25 bar and with high purity oxygen (at least 90% pure) to reduce the residence time at high yield.

Abstract: A process for extracting hydrogen fluoride from fluorine containing materials includes countercurrently contacting the materials with steam having a plane of rotation relatively perpendicular to the direction of flow of the material. An apparatus for the extraction of hydrogen fluoride from fluorine containing materials includes a rotary kiln having a first zone wherein a steam-air mixture countercurrently contacts the materials in an oxidation step, a second zone wherein an oxygen containing gas is tangentially injected into the kiln to provide complete combustion of carbon containing materials, a third zone wherein a steam stream countercurrently contacts the materials in a reducing step and means for providing a plane of rotation to the steam which is relatively perpendicular to the direction of flow of the material.

Abstract: A method for continuously extracting uranium from ores comprises the steps of forming a slurry of ore in a leaching solution; heating the slurry while pumping it through a tube reactor at high turbulences characterized by Reynolds numbers in excess of 50,000; supplying gaseous oxygen at high pressures of at least 30 bar into the tube reactor such that the uranium is substantially completely oxidized in a soluble form but impurities in the slurry are substantially kept from becoming soluble; recovering the uranium oxide solute which is substantially free of impurities.

Abstract: Disclosed herein are a process and apparatus for manufacturing vanadium pentoxide in powder form by the thermal decomposition of ammonium metavanadate containing more than 10% NH.sub.3 in a single operation.

Abstract: A process for extracting hydrogen fluoride from fluorine containing materials includes countercurrently contacting the materials with steam having a plane of rotation relatively perpendicular to the direction of flow of the material. An apparatus for the extraction of hydrogen fluoride from fluorine containing materials includes a rotary kiln having a first zone wherein a steam-air mixture countercurrently contacts the materials in an oxidation step, a second zone wherein an oxygen containing gas is tangentially injected into the kiln to provide complete combustion of carbon containing materials, a third zone wherein a steam stream countercurrently contacts the materials in a reducing step and means for providing a plane of rotation to the steam which is relatively perpendicular to the direction of flow of the material.

Abstract: Disclosed herein are a process and apparatus for manufacturing vanadium pentoxide in powder form by the thermal decomposition of ammonium metavanadate containing more than 10% NH.sub.3 in a single operation.