Recovery of commercial substances from apatite mineral

A method for recovery of commercial gypsum from apatite mineral, comprising the steps of:

• dissolving apatite mineral of magmatic origin in an acid comprising hydrochloride, giving a first liquid solution comprising phosphate ions, calcium ions and chloride ions;
• treating said first liquid solution, resulting in a second liquid solution comprising calcium ions and chloride ions;
• said step of treating in turn comprising the step of extracting a major part of said phosphate ions with an organic solvent;
• removing a bleed solution from said second solution;
• adding lime into said bleed solution, resulting in precipitation of calcium phosphate, removing said precipitated calcium phosphate from said bleed solution, and recirculating said removed precipitated calcium phosphate to be dissolved together with said apatite mineral in a subsequent said step of dissolving apatite mineral in an acid;
• and
• precipitating solid gypsum comprising at least 70% in a di-hydrate crystal form from said second solution;
• said step of precipitating solid gypsum in turn comprising the step of adding said second solution and sulfuric acid simultaneously into a continuous-stirred reactor in the presence of gypsum crystals, whereby said precipitating of solid gypsum gives a third liquid solution comprising hydrochloride;
• said sulfuric acid has a concentration of at least 13 M.

A method for recovery of commercial gypsum from apatite mineral, comprising the steps of:

• dissolving apatite mineral of magmatic origin in an acid comprising hydrochloride, giving a first liquid solution comprising phosphate ions, calcium ions and chloride ions;
• treating said first liquid solution, resulting in a second liquid solution comprising calcium ions and chloride ions;
• said step of treating in turn comprising the step of extracting a major part of said phosphate ions with an organic solvent at an organic-to-aqueous ratio of between 1:1 and 3:1, in at least 4 contact stages;
• removing a bleed solution from said second solution;
• and
• precipitating solid gypsum comprising at least 70% in a di-hydrate crystal form from said second solution;
• said step of precipitating solid gypsum in turn comprising the step of adding said second solution and sulfuric acid simultaneously into a continuous-stirred reactor in the presence of gypsum crystals, whereby said precipitating of solid gypsum gives a third liquid solution comprising hydrochloride;
• said sulfuric acid has a concentration of at least 13 M.