Abstract: An improved process for extending the capabilities of an existing, conventional wet-process phosphoric acid production plant to more effectively utilize phosphate values contained in low purity phosphate rock which process comprises (1) adjustment of the maximum soluble sulfate level in phosphoric acid taken from, for example, the conventional wet-process acid facility prior to reacting same with such low purity phosphate rock, in combination therewith, and (2) control of the parameters of (a) ratio of attack acid to feed rock, (b) reaction temperature, and (c) reaction time. Said improved process effects selective dissolution of calcium and phosphate values from such rock without incurring unwanted and undesired high codissolution of congeneric aluminum and iron impurities therein.

Abstract: A phosphate ore flotation process comprising subjecting a phosphate ore containing surface-activated silica and silicates to froth flotation in the presence of a fatty-acid collector, recovering the phosphate concentrate from the overflow; removing the fatty acid collector from the phosphate concentrate in the presence of a sulfuric acid deoiling agent; subjecting the phosphate concentrate to a reversed froth flotation in the presence of a silica collector and a modifier, said silica collector being an amine and said modifier being either alkyl diphosphonic acid, or being HF; removing the separated silica from the overflow; and recovering the phosphate product in the underflow. The process of the present invention not only overcomes the problems of activated silica flotation, but also results in greatly improved grade and/or recovery of phosphate product in comparison to present conventional phosphate ore flotation processing.

Abstract: A phosphate ore flotation process subjecting a phosphate ore containing carbonate mineral impurities to froth flotation in the presence of modifying agents, said modifying agents being alkyl phosphonic acids and hydrofluoric acid, and a collector, said collector being fatty acids; collecting the phosphate and carbonate minerals as rougher concentrate from the overflow; subjecting the phosphate and carbonate mineral concentrate to a differential desorption with an acid to remove the fatty acid from the surface of the phosphate mineral; removing the separated carbonate minerals from the overflow; and recovering the phosphate values in the underflow.

Abstract: A phosphate ore flotation process subjecting a phosphate ore containing carbonate mineral impurities to froth flotation in the presence of phosphate depressants, said depressants are alkyl phosphonic acids, and a carbonate collector, said collector is fatty acids, removing the separated carbonate minerals from the overflow, and recovering the phosphate value in the underflow. The process of the present invention can be performed either prior to or after the separation of siliceous matter from phosphate minerals by methods known in the art.

Abstract: mixtures of the isomers of C.sub.18 and C.sub.16 branched-chain saturated fatty acids have been demonstrated to be satisfactory substitutes as flotation reagents in Florida phosphate rock flotation in place of commercial crude, refined, or blended tall oils, or other straight-chain aliphatic fatty acids derived from vegetive sources in which the unsaturated aliphatic fatty acid components are the principal or most effective flotation reagents, as opposed to the corresponding saturated straight-chain fatty acids. The title reagents consisting of saturated branched-chain fatty acids of similar carbon content (C.sub.16 - C.sub.18) can be used alone as acids, or as soap derivatives, or in blended mixtures with fuel oil, which reduces reagent comsumption and also increases the grade and recovery of phosphate concentrate.

Abstract: A phosphate ore beneficiation process to remove undesirable carbonate mineral components by flotation by subjecting a deslimed phosphate ore flotation feed containing the carbonate mineral impurities to a froth flotation treatment in the presence of a phosphate depressant, said depressant being alkyl phosphonic acids including alkyl diphosphonic acids such as hydroxyethylidene diphosphonic acid, and a carbonate mineral collector reagent, said collector being a fatty acid or mixtures thereof; removing the carbonate mineral overflow so obtained by froth flotation; and recovering the phosphate value in the underflow product of said flotation process. The process can be performed either prior to or after the conventional flotation separation treatment for removing siliceous mineral contaminants from the phosphate mineral by methods known to the art.

Abstract: A phosphate ore flotation process subjecting a phosphate ore containing carbonate mineral impurities to froth flotation in the presence of modifying agents, said modifying agents being alkyl phosphonic acids and hydrofluoric acid, and a collector, said collector being fatty acids; collecting the phosphate and carbonate minerals as rougher concentrate from the overflow; subjecting the phosphate and carbonate mineral concentrate to a differential desorption with an acid to remove the fatty acid from the surface of the phosphate mineral; removing the separated carbonate minerals from the overflow; and recovering the phosphate values in the underflow.

Abstract: A phosphate ore flotation process comprising subjecting a phosphate ore containing surface-activated silica and silicates to froth flotation in the presence of a fatty-acid collector, recovering the phosphate concentrate from the overflow; removing the fatty acid collector from the phosphate concentrate in the presence of a sulfuric acid deoiling agent; subjecting the phosphate concentrate to a reverse froth flotation in the presence of a silica collector and a modifier, said silica collector being an amine and said modifier being either alkyl diphosphonic acid, or being HF; removing the separated silica from the overflow; and recovering the phosphate product in the underflow. The process of the present invention not only overcomes the problems of activated silica flotation, but also results in greatly improved grade and/or recovery of phosphate product in comparison to present conventional phosphate ore flotation processing.

Abstract: Adjustment of the maximum soluble sulfate level in phosphoric acid taken from, for example, an existing, conventional wet-process phosphoric acid production facility prior to reacting same with low purity phosphate rock at a temperature ranging from 45.degree. C. to 65.degree. C. and for a period of time ranging from about 10 minutes to 60 minutes effects selective dissolution of calcium and phosphate values from the rock without incurring high codissolution of aluminum and iron impurities. After separation from the undissolved impurity-containing gangue, the resulting solution of calcium phosphate in phosphoric acid is returned to the conventional wet-process facility for subsequent treatment with sulfuric acid to produce phosphoric acid and calcium sulfate, while the gangue is washed to recover additional phosphate values, and the wash liquor is transported to the conventional facility where it is used to wash the calcium sulfate filter cake.