Abstract: A method for preparing phosphoric acid from calcium phosphate ores, particularly ores highly contaminated with organic compounds, by decomposing the ore with sulphuric acid, wherein according to the invention the process of decomposition of calcium phosphate ores with sulphuric acid and circulating phosphoric acid is carried out in oxidizing conditions provided by a constant supply of ozone to the reaction slurry, preferably to the zone of commencing decomposition of the phosphate ores.

Abstract: A boiler noise suppressor has one truss (2) mounted on a cover of an inlet flange (1), a perforated expansion nozzle (5), a pipe system (7) made of a several hundreds of pipes, a perforated outlet nozzle (8), at least one truss (11) mounted on a collar of the outlet nozzle. The pipe system (7) can be additionally cooled in a parallel-current- or a counter-current manner preferably by air or water. The boiler noise suppressor can be connected directly to the exhaust of blow-out steam of a single boiler or in a parallel connection to form batteries of suppressors by a connection with exhausts of blow-out steam from several boilers. The application of the noise suppressor renders it possible to reduce the noise level by more than 50% from 140-160 dB to 70-80 dB.

Abstract: Method of production of synthetic fluorite with a selected specified grain size to be obtained, by submitting the calcium carbonate to a reaction with fluoride ions present in an aqueous solution, consists therein that calcium carbonate is used having a grain size substantially the same as the selected grain size for the synthetic fluorite to be obtained. The fluoride ions for the reaction with the calcium carbonate are supplied in the form of a solution of ammonium fluoride and/or potassium fluoride and/or sodium fluoride. The process is conducted at a temperature chosen within the range of 50.degree. C to 150.degree. C, under a pressure reduced, atmospheric or elevated, within the range of 0.5 to 10 atm, and preferably at the boiling temperature or at a temperature not too far from the boiling point, especially in a reaction system containing ammonium fluoride.