A material, especially a glassy material of pyrophosphate type, corresponding to the general formula (I): {[(M.sup.2+).sub.1x(R.sup.+).sub.2x].sub.2[(P.sub.2O.sub.7.sup.4).sub.1y(PO.sub.4.sup.3).sub.4y/3]} n(H.sub.2O) in which x and y are positive rational numbers each between 0 and 0.8, and n is such that the weight percentage of water in the material is greater than 0 and less than or equal to 95. M.sup.2+ represents a bivalent ion of a metal chosen from calcium, magnesium, strontium, copper, zinc, cobalt, manganese and nickel, or any mixture of such bivalent ions. R.sup.+ represents a monovalent ion of a metal selected from potassium, lithium, sodium, and silver, or any mixture of such monovalent ions. This material in particular can be used in manufacturing of bone replacements or prosthesis coatings.

A material, especially a glassy material of pyrophosphate type, corresponding to the general formula (I): {[(M.sup.2+).sub.1x(R.sup.+).sub.2x].sub.2[(P.sub.2O.sub.7.sup.4).sub.1y(PO.sub.4.sup.3).sub.4y/3]} n(H.sub.2O) in which x and y are positive rational numbers each between 0 and 0.8, and n is such that the weight percentage of water in the material is greater than 0 and less than or equal to 95. M.sup.2+ represents a bivalent ion of a metal chosen from calcium, magnesium, strontium, copper, zinc, cobalt, manganese and nickel, or any mixture of such bivalent ions. R.sup.+ represents a monovalent ion of a metal selected from potassium, lithium, sodium, and silver, or any mixture of such monovalent ions. This material in particular can be used in manufacturing of bone replacements or prosthesis coatings.

Techniques are described for preparing a water filtration composition that includes activated carbon having an ash content of at least 10 wt. % and particles of a solubilizing agent. The solubilizing agent forms a water-soluble complex with cations (e.g., calcium ions). This increases the solubility of calcium ions and other scale-forming ions in water, thus suppressing scale formation on interior surfaces of water processing infrastructure. The activated carbon and the solubilizing agent are processed to have particle sizes in a same range, thus enabling the activated carbon and the solubilizing agent to be thoroughly mixed together.

Techniques are described for preparing a water filtration composition that includes activated carbon having an ash content of at least 10 wt. % and particles of a solubilizing agent. The solubilizing agent forms a water-soluble complex with cations (e.g., calcium ions). This increases the solubility of calcium ions and other scale-forming ions in water, thus suppressing scale formation on interior surfaces of water processing infrastructure. The activated carbon and the solubilizing agent are processed to have particle sizes in a same range, thus enabling the activated carbon and the solubilizing agent to be thoroughly mixed together.

Polyphosphate compositions are produced by a process that includes the steps of continuously introducing a phosphate compound into a polymerization vessel, polymerizing the phosphate compound at a temperature of 250-450? C. for a time period sufficient to form the polyphosphate composition, and continuously discharging the polyphosphate composition from the polymerization vessel. The phosphate compound can be fed to the polymerization vessel in the form of an aqueous slurry containing 5-50 wt. % of the phosphate compound. Resulting polyphosphate compositions often contain at least 8 wt. % of a polyphosphate and less than 35 wt. % of the phosphate compound.

The present invention enables to provide plate-like titanium pyrophosphate, having both high uniformity in size and specific particle shape, which is expected to be highly useful. The present invention relates to plate-like titanium pyrophosphate having an aspect ratio of 5 or more expressed as a ratio of the in-plane length D.sub.PL50 of primary particles, at which the cumulative frequency from the smaller particle size side is 50% in a volume-based cumulative particle size distribution, to the thickness D.sub.PT50 of primary particles, at which the cumulative frequency from the smaller particle size side is 50% in a volume-based cumulative particle size distribution (the in-plane length D.sub.PL50 of primary particles/the thickness D.sub.PT50 of primary particles), wherein the relationship among the particle size D10 of secondary particles, at which the cumulative frequency from the smaller particle size side is 10% in a volume-based cumulative particle size distribution, the particle size D50 of secondary particles, at which the cumulative frequency from the smaller particle size side is 50% in a volume-based cumulative particle size distribution, and the particle size D90 of secondary particles, at which the cumulative frequency from the smaller particle size side is 90% in a volume-based cumulative particle size distribution, satisfies a specific relationship; and a method for producing the same.

The present invention enables to provide plate-like titanium pyrophosphate, having both high uniformity in size and specific particle shape, which is expected to be highly useful. The present invention relates to plate-like titanium pyrophosphate having an aspect ratio of 5 or more expressed as a ratio of the in-plane length D.sub.PL50 of primary particles, at which the cumulative frequency from the smaller particle size side is 50% in a volume-based cumulative particle size distribution, to the thickness D.sub.PT50 of primary particles, at which the cumulative frequency from the smaller particle size side is 50% in a volume-based cumulative particle size distribution (the in-plane length D.sub.PL50 of primary particles/the thickness D.sub.PT50 of primary particles), wherein the relationship among the particle size D10 of secondary particles, at which the cumulative frequency from the smaller particle size side is 10% in a volume-based cumulative particle size distribution, the particle size D50 of secondary particles, at which the cumulative frequency from the smaller particle size side is 50% in a volume-based cumulative particle size distribution, and the particle size D90 of secondary particles, at which the cumulative frequency from the smaller particle size side is 90% in a volume-based cumulative particle size distribution, satisfies a specific relationship; and a method for producing the same.

Provided are a cathode active material for a sodium ion secondary battery that is excellent in alkali ion diffusivity, structural stability, and cycle performance, and a synthesis method therefor. The cathode active material for a sodium ion secondary battery includes a melt-solidified body or oxide glass represented by the general formula Na.sub.xM.sub.yP.sub.2O.sub.7 (where M represents at least one or more kinds of transition metal elements selected from Cr, Fe, Mn, Co, and Ni, x satisfies a relationship of 1.20x2.10, and y satisfies a relationship of 0.95y1.60).

Provided are a cathode active material for a sodium ion secondary battery that is excellent in alkali ion diffusivity, structural stability, and cycle performance, and a synthesis method therefor. The cathode active material for a sodium ion secondary battery includes a melt-solidified body or oxide glass represented by the general formula Na.sub.xM.sub.yP.sub.2O.sub.7 (where M represents at least one or more kinds of transition metal elements selected from Cr, Fe, Mn, Co, and Ni, x satisfies a relationship of 1.20x2.10, and y satisfies a relationship of 0.95y1.60).

Provided is a powder containing ferric pyrophosphate that affords high iron absorbability, as a main component of an oral iron preparation. The present invention relates to a composite powder containing ferric pyrophosphate, which is a powder containing ferric pyrophosphate and a sodium component, wherein (1) the content of ferric pyrophosphate is 95 wt % or higher, and (2) a (Fe+Na)/P molar ratio is 0.8 to 1.0.