A polyphosphate material is disclosed. The polyphosphate material can include a plurality of polyphosphate chains. The polyphosphate chains can have a backbone that include oxygen-phosphate bonds. Two or more cations can be included. Further, the polyphosphate material can be amorphous. The two or more cations can be monovalent cations, divalent cations, trivalent cations, tetravalent cations, and combinations thereof. The two or more cations can be lithium, sodium, potassium, rubidium, cesium, francium, ammonium, beryllium, magnesium, calcium, strontium, barium, radium, zinc, titanium, iron (Fe.sup.2+), chromium (Cr.sup.2+), manganese (Mn.sup.2+), cobalt (Co.sup.2+), nickel (Ni.sup.2+), copper (Cu.sup.2+), cadmium, tin (Sn.sup.2+), mercury (Hg.sup.2+), lead (Pb.sup.2+), aluminum, boron, gallium, iron (Fe.sup.+3), chromium (Cr.sup.+3), cobalt (Co.sup.+3), gold (Au.sup.+3), antimony (Sb.sup.+3), nickel (Ni.sup.+3), bismuth (Bi.sup.+3), manganese (Mn.sup.+3) zirconium, silicon, and combinations of thereof. The two or more cations can be monovalent cations. The two or more cations can be sodium and potassium or potassium and lithium.

The invention is related to a flotation process using an improved collector to remove alkaline earth metal carbonate impurities from phosphate ores. The flotation feed may be conditioned with the improved carbonate collector at acidic pH, and subjected to a reverse flotation. The cell overflow may be collected as waste in which carbonate minerals dominate, and the cell underflow may be the phosphate concentrate. The collector may be a combination of chemicals, comprising: (1) any kind of fatty acids, either conventional fatty acid, saponified fatty acid, or modified fatty acid; (2) chemicals with sulfonate or sulfate groups, such as dodecylbenzene sulfonic acid (DDBSA) or its salt, sodium dodecyl sulfate (SDS), sodium lauryl sulfate (SLS), sodium coco sulfate (SCS), etc.; and (3) phosphorous-bearing chemicals, such as sodium tripolyphosphate (STPP), sodium hexametaphosphate (SFMP), trisodium phosphate (TSP), Tetrasodiumpyrophosphate (TSPP), etc. With the improved collector, the separation selectivity and phosphate recovery may be significantly improved.

The invention is related to a flotation process using an improved collector to remove alkaline earth metal carbonate impurities from phosphate ores. The flotation feed may be conditioned with the improved carbonate collector at acidic pH, and subjected to a reverse flotation. The cell overflow may be collected as waste in which carbonate minerals dominate, and the cell underflow may be the phosphate concentrate. The collector may be a combination of chemicals, comprising: (1) any kind of fatty acids, either conventional fatty acid, saponified fatty acid, or modified fatty acid; (2) chemicals with sulfonate or sulfate groups, such as dodecylbenzene sulfonic acid (DDBSA) or its salt, sodium dodecyl sulfate (SDS), sodium lauryl sulfate (SLS), sodium coco sulfate (SCS), etc.; and (3) phosphorous-bearing chemicals, such as sodium tripolyphosphate (STPP), sodium hexametaphosphate (SFMP), trisodium phosphate (TSP), Tetrasodiumpyrophosphate (TSPP), etc. With the improved collector, the separation selectivity and phosphate recovery may be significantly improved.

A composite positive electrode active material is disclosed. The composite positive electrode active material includes a first lithium iron manganese phosphate type material and a second lithium iron manganese phosphate type material. The first lithium iron manganese phosphate type material has a nanosheet structure, and a ratio of an area of a (010) crystal plane of the first lithium iron manganese phosphate type material to a total area of crystal planes of the first lithium iron manganese phosphate type material is A.sub.1%. The second lithium iron manganese phosphate type material has a spherical and/or quasi-spherical structure, and a ratio of an area of a (010) crystal plane of the second lithium iron manganese phosphate type material to a total area of crystal planes of the second lithium iron manganese phosphate type material is A.sub.2%. The composite positive electrode active material satisfies A.sub.1>A.sub.2.