An object of the present invention is to provide a calcium phosphate powder that enables the preparation of a slurry for additive manufacturing with excellent dispersion stability, and enables the production of a three-dimensional additive manufacturing article with high strength, in additive manufacturing. Provided is a calcium phosphate powder, having an average particle size (D.sub.50) of 0.1 to 5.0 μm, and having a pore volume of mesopores (pore size: 2 to 50 nm) of 0.01 to 0.06 cc/g as measured by a gas adsorption method. The calcium phosphate powder has excellent dispersion stability in a slurry for additive manufacturing, and, by performing additive manufacturing using a slurry for additive manufacturing containing the calcium phosphate, it is possible to produce a three-dimensional additive manufacturing article with high strength, which is useful as an implant, such as an artificial bone.

The present invention provides that powder is mainly constituted from secondary particles of hydroxyapatite. The secondary particles are obtained by drying a slurry containing primary particles of hydroxyapatite and aggregates thereof and granulating the primary particles and the aggregates. A bulk density of the powder is 0.65 g/mL or more and a specific surface area of the secondary particles is 70 m.sup.2/g or more. The powder of the present invention has high strength and is capable of exhibiting superior adsorption capability when it is used for an adsorbent an adsorption apparatus has.

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 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.

An object of the present invention is to provide anhydrous dibasic calcium phosphate having good powder flowability and good dispersibility in water. An anhydrous dibasic calcium phosphate powder containing agglomerated particles formed by agglomerating anhydrous dibasic calcium phosphate particles having a modal pore diameter/mean particle diameter ratio of 0.2 to 0.34 exhibits good powder flowability and good dispersibility in water.

The present invention relates to a method of converting limestone into tri-calcium phosphate (TCP) and tetra-calcium phosphate (TTCP) powder simultaneously. In particular, the method provides for a method of converting limestone into TCP and TTCP powder simultaneously having specific particle size and with specific crystallographic structure.

The present invention provides that powder is mainly constituted from secondary particles of hydroxyapatite. The secondary particles are obtained by drying a slurry containing primary particles of hydroxyapatite and aggregates thereof and granulating the primary particles and the aggregates. A bulk density of the powder is 0.65 g/mL or more and a specific surface area of the secondary particles is 70 m.sup.2/g or more. The powder of the present invention has high strength and is capable of exhibiting superior adsorption capability when it is used for an adsorbent an adsorption apparatus has.

According to the present invention, provided is a carbonate- and magnesium-substituted hydroxyapatite having a particle size of 5 nm or more and 60 nm or less, wherein a portion of the calcium atoms in the hydroxyapatite are substituted with magnesium atoms and a portion of phosphate groups are substituted with carbonate groups.

In order to provide a hydroxyapatite that can be used without reservation in the food industry, a hydroxyapatite powder is provided composed of primary particles. The median size of the primary particles from which the powder is made is >0.10 μm and the aspect ratio of the primary particles is <5. The specific surface area of the hydroxyapatite powder is ≤10 m.sup.2/g, and the bulk density is >550 g/l. Also disclosed is a method with which such a hydroxyapatite powder can be obtained.

The present invention provides that powder is mainly constituted from secondary particles of hydroxyapatite. The secondary particles are obtained by drying a slurry containing primary particles of hydroxyapatite and aggregates thereof and granulating the primary particles and the aggregates. A bulk density of the powder is 0.65 g/mL or more and a specific surface area of the secondary particles is 70 m.sup.2/g or more. The powder of the present invention has high strength and is capable of exhibiting superior adsorption capability when it is used for an adsorbent an adsorption apparatus has.