The invention relates to calcium hydroxyapatite particles having been sintered at a certain temperature range and which are not treated at a temperature above this range. Furthermore, the present invention relates to an injectable composition comprising such particles and to uses thereof. Surprisingly, it was found that the particles of the invention are superior over calcium hydroxyapatite particles known in the art with respect to bio-stimulation.

A source of phosphate for agriculture and food industry comprises a phosphate salt in solid form of formula M.sub.n(HPO4)y.zH2O in which M is Na, K, NH4, n=2, and y=1; or M is Ca, n=1, y=1; or M is Al or Fe, n=2, y=3; and in which z is 0, 1 or 2, wherein said phosphate salt has a phosphate content expressed as a P2O5 content of between 30 and 50% by weight of the phosphate salt, and it has a cadmium content lower than 0.40 ppm.

This disclosure relates to a method for the preparation of calcium monohydrogen phosphate comprising an etching in an aqueous medium, during a predetermined time period, a source of phosphate with an acid with formation of a pulp comprising an aqueous phase containing calcium phosphate in solution and a solid phase containing impurities, a first separation between said aqueous phase and said solid phase, during a predetermined time period, a neutralization of said aqueous phase at a sufficient pH to obtain a precipitation of said calcium monohydrogen phosphate, a second separation between said aqueous medium and said calcium monohydrogen phosphate, characterized in that said predetermined time period of said step a) of digestion is greater than that of said step b).

A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO.sub.3 equal to or less than 1.5% and a content of free P.sub.2O.sub.5, a conversion of at least part of said first slurry by heating to a temperature greater than 80 C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of -calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO.sub.3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure -calcium sulphate hemihydrate.

This present invention disclosure relates to a method for the preparation of calcium monohydrogen phosphate comprising an etching in an aqueous medium, during a predetermined time period, of a phosphate source with an acid with formation of a pulp comprising an aqueous phase containing calcium phosphate in solution and a solid phase containing impurities, a first separation between said aqueous phase and said solid phase, during a predetermined time period, a neutralization of said aqueous phase at a sufficient pH to obtain a precipitation of said calcium monohydrogen phosphate, a second separation between said aqueous medium and said calcium monohydrogen phosphate, characterized in that said first separation of said step b) is carried out at a filtration rate of at least 0.1 ton of P.sub.2O.sub.5/P/m.sup.2/day.

The present invention relates to a method for purifying raw phosphoric acid by adding ashes originating from waste incineration plants, as well as calcium hydroxide and at least one sulfide, and by wet-chemical digestion for obtaining (producing) calcium sulfate, pure phosphoric acid, metal salt solution and/or calcium hydrogen phosphates (e.g. triple superphosphate).

Herein is described a method for the manufacture of a charge director comprising a barium salt. The method comprises reacting barium alkoxide with an acid in a reaction medium comprising ethanol, and separating ethanol from the reaction mixture to recover the barium salt produced.

A method for complex treatment of phosphogypsum comprising crushing of phosphogypsum and its washing with a solution of sulphuric acid, concentration 2-15%, and stirring at 50-80 C., wherein the resultant mixture is separated into a liquid fraction and a sediment containing mostly calcium sulphate, which is characterized in that metals are precipitated from the liquid fraction, mainly lanthanides, phosphates and sulphates of metals soluble in diluted sulphuric acid, and the sediment containing mostly calcium sulphate is converted in the presence of ammonia liquor and carbon dioxide to ammonium sulphate and calcium carbonate, wherein filtered and dried sediment of calcium carbonate is dissolved in a 15-30% solution of nitric acid while stirring continuously, and then the resultant CO.sub.2 is recirculated and used in the conversion of the first phase of the sediment, and the resultant mixture is separated into a solution of calcium nitrate with dissolved metals and a sediment of fluorides and silicates with metal precipitate.

Herein is described a method for the manufacture of a charge director comprising a barium salt. The method comprises reacting barium alkoxide with an acid in a reaction medium comprising ethanol, and separating ethanol from the reaction mixture to recover the barium salt produced.

A method and apparatus of preparing lithium compound(s) from lithium-containing mineral includes a) a leaching step, wherein the lithium-containing mineral is leached in aqueous leach solution containing alkaline carbonate, for liberating lithium and phosphate(s) from the lithium-containing mineral, thus obtaining leach slurry containing lithium carbonate and phosphate(s) leach slurry, b) a carbonization step, wherein the leach slurry containing lithium carbonate and phosphate(s), obtained from the leaching step, is reacted with an alkali earth metal compound in the presence of CO.sub.2 for obtaining a carbonated slurry containing lithium hydrogen carbonate, and for precipitating phosphate(s) contained in the leach slurry as insoluble phosphate compound(s), c) a solid-liquid separation step, wherein the carbonated slurry obtained from carbonization step is subjected to solid-liquid separation wherein the undissolved mineral and phosphate compound(s) are separated as solids that can be recovered or discarded, thereby obtaining a solution containing lithium hydrogen carbonate.