Provided is a negative electrode active material for a lithium secondary battery including: a silicon oxide (SiO.sub.x, 0<x≤2) composite including an alkali metal or alkaline earth metal-containing phosphate; and an aluminum-containing phosphate.

A system and method for treatment of wastewater, in which the system includes a blackwater reactor configured to receive a stream of blackwater influent, to contain the blackwater therein during treatment of the blackwater, to facilitate recovery of methane and nutrient precipitates therefrom, and to output partially treated blackwater, and a greywater reactor configured to receive a stream of greywater influent and the partially treated blackwater output from the blackwater reactor, to contain the greywater and the partially treated blackwater therein during greywater treatment, and to output greywater treatment discharge. The process includes inputting a stream of blackwater into the blackwater reactor; treating the blackwater in the blackwater reactor with an anaerobic digestion process; controlling a pH level of the blackwater within the blackwater reactor; recovering nutrient precipitates from the blackwater reactor, optionally independent of chemical additives; and recovering methane from the blackwater reactor.

A whitlockite preparation method includes: determining a size of the whitlockite crystal to be prepared; determining a first amount of a first cation other than calcium ion on the basis of the determined size of the crystal, wherein when the determined size of the whitlockite crystal is a first size, the first amount is determined to be a first value, wherein when the determined size is a second size larger than the first size, the first amount is determined to be a second value; mixing calcium ion and phosphate ion in order to prepare a first phosphate crystal, wherein the determined first amount of the cation other than calcium ion is also mixed therewith; mixing a second amount of cation other than calcium ion with phosphate ion to prepare a second phosphate crystal; and aging a solution containing the first phosphate crystal and the second phosphate crystal.

A whitlockite preparation method includes: determining a size of the whitlockite crystal to be prepared; determining a first amount of a first cation other than calcium ion on the basis of the determined size of the crystal, wherein when the determined size of the whitlockite crystal is a first size, the first amount is determined to be a first value, wherein when the determined size is a second size larger than the first size, the first amount is determined to be a second value; mixing calcium ion and phosphate ion in order to prepare a first phosphate crystal, wherein the determined first amount of the cation other than calcium ion is also mixed therewith; mixing a second amount of cation other than calcium ion with phosphate ion to prepare a second phosphate crystal; and aging a solution containing the first phosphate crystal and the second phosphate crystal.

The invention relates to a method for producing an osteotropic bone replacement material from a starting material which substantially has portlandite, calcium oxide, aragonite; calcite and/or apatite. The starting material is introduced into an autoclave with a strontium, fluorine and/or gallium source, wherein when using a starting material which substantially has portlandite, calcium oxide, aragonite; calcite a phosphate source is introduced. In addition, H.sub.2O is added into the autoclave as part of a solvent and the pH value in the autoclave is set to a range above 7. Afterwards, the closed and filled autoclave is heated for at least 1 hour and then cooled. The osteotropic bone replacement material thus developed is subsequently cleaned from residues of the phosphorus, strontium, fluorine and/or gallium source. Furthermore, the invention relates to an osteotropic bone replacement material which substantially consists of apatite and in which strontium ions are incorporated into the crystal lattice.

To provide a ceramic particle separable composite material having a calcium phosphate sintered body particle with which bioaffinity reduction and solubility change are suppressed as much as possible and which has a smaller particle diameter. A ceramic particle separable composite material comprising a ceramic particle and a substrate, wherein: the ceramic particle and the substrate are chemically bonded to each other, or the ceramic particle physically adheres to or is embedded in the substrate; the ceramic particle has a particle diameter within a range of 10 nm to 700 nm; the ceramic particle is a calcium phosphate sintered body particle; and the ceramic particle contains no calcium carbonate.

To provide a ceramic particle separable composite material having a calcium phosphate sintered body particle with which bioaffinity reduction and solubility change are suppressed as much as possible and which has a smaller particle diameter. A ceramic particle separable composite material comprising a ceramic particle and a substrate, wherein: the ceramic particle and the substrate are chemically bonded to each other, or the ceramic particle physically adheres to or is embedded in the substrate; the ceramic particle has a particle diameter within a range of 10 nm to 700 nm; the ceramic particle is a calcium phosphate sintered body particle; and the ceramic particle contains no calcium carbonate.

The present invention relates to a method of quickly preparing a large amount of octacalcium phosphate and octacalcium phosphate prepared thereby. A method of preparing octacalcium phosphate according to an embodiment of the present invention includes preparing a calcium phosphate solution, controlling an initial pH by controlling a pH of the calcium phosphate solution to a range from 5 to 6 using an acidic solution at a time point at which the pH of the calcium phosphate solution increases, heating the calcium phosphate solution to a temperature ranging from 60° C. to 90° C., and controlling a terminal pH by controlling the pH of the calcium phosphate solution to a range from 5 to 6 using a basic solution at a time point at which the pH of the heated calcium phosphate solution decreases.

The present invention relates to a method of quickly preparing a large amount of octacalcium phosphate and octacalcium phosphate prepared thereby. A method of preparing octacalcium phosphate according to an embodiment of the present invention includes preparing a calcium phosphate solution, controlling an initial pH by controlling a pH of the calcium phosphate solution to a range from 5 to 6 using an acidic solution at a time point at which the pH of the calcium phosphate solution increases, heating the calcium phosphate solution to a temperature ranging from 60° C. to 90° C., and controlling a terminal pH by controlling the pH of the calcium phosphate solution to a range from 5 to 6 using a basic solution at a time point at which the pH of the heated calcium phosphate solution decreases.

A process for producing a calcium phosphate reactant, according to which: in a first step, use is made of a source of calcium and a source of phosphate ions in water, in a molar ratio that is adjusted so as to obtain a Ca/P molar ratio of between 0.5 and 1.6, and the source of calcium is reacted with the phosphate ions at a pH of between 2 and 8, in order to obtain a suspension (A) of calcium phosphate, and in a second step, added to the suspension (A) are an alkaline compound comprising hydroxide ions in order to set a pH of more than 8 and an additional source of calcium in order to obtain a suspension (B) of calcium phosphate reactant having a Ca/P molar ratio of more than 1.6. A calcium phosphate reactant obtainable by such a process.