Abstract: An extraction process for extracting ionic values from an aqueous solution containing same which comprises contacting the aqueous solution with an organic hydrophobic liquid extractant phase comprising an extractant for ions, the molecules of which extractant contain at least one hydrophobic group selected from cyclic phosphazene radicals, linear siloxane radicals, cyclic siloxane radicals, and three-dimensional siloxane radicals, and stripping resulting loaded extractant phase with an aqueous stripping liquid phase.

Abstract: In a process according to the present invention pre-reduced lateritic ores containing iron and nickel are leached with an aqueous sulphuric acid leach liquor containing or into which is introduced in the presence of the ore a peroxidant selected from hydrogen peroxide and peroxymonosulphuric acid. By so doing, the liquor is obtained with a lower concentration of iron than if the peroxidant had not been employed.In preferred embodiments the leaching is carried out at from 40.degree. to 70.degree. C. for a period of 1 to 5 hours; when hydrogen peroxide is used, it is preferably introduced continuously or progressively throughout the reaction period and when peroxymonosulphuric acid is used it is preferably introduced initially. The acidity of the liquor can be reduced at the end of the reaction to pH3 to 4 to further lower the content of iron in solution.

Abstract: The invention relates to the production of tungsten having a low impurity content of molybdenum from impure minerals such as scheelite.An aqueous acidic feed solution containing both molybdenum and tungsten, and also containing enough hydrogen peroxide to depolymerize heteropolymers of tungsten and molybdenum and prevent precipitation in the extractant, is contacted with an extractant composition comprising an organic phosphoric acid, a trialkyl phosphate and a tri-alkyl phosphine oxide in an hydrocarbon diluent. By selecting an appropriate combination of pH and hydrogen peroxide content of the feed, contents of the components of the extraction composition and temperature of extraction, selective extraction of molybdenum can be obtained. In some particularly preferred embodiments, the feed pH is in the range of 0.85 to 1.5, the mole ratio of hydrogen peroxide to tungsten and molybdenum is 0.6 to 1.0, the temperature of extraction is in the range 12.degree. to 20.degree. C.

Abstract: The present invention relates to a process for the recovery of manganese from aqueous acidic solution.The process comprises the steps of, (a) introducing into the solution peroxymonosulphuric acid (PMS) in a plurality of stages, normally from 2 to 6, often in the range of from 110 to 160% of the amount theoretically needed to oxidise the manganese to the Mn (IV) oxidation state, (b) introducing from 100 to 133% of the theoretical amount of neutralising agent to neutralise the PMS introduced in step (a), preferably in a single addition and prior to the introduction of the second stages of PMS and, (c) separating precipitated manganese salt from solution. The demanganisation reaction is preferably carried out at a temperature of above 60.degree. C. usually in the range of 70.degree. to 90.degree. C.An aqueous acidic manganese-containing solution can be obtained by leaching ores or scrap metal with strong mineral acids.