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.

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.

Methods are disclosed for producing a calcium phosphate salt comprising reacting fluorosilicic acid (FSA) with water and a calcium phosphate source to produce phosphoric acid, calcium fluoride, and silicon dioxide; removing residual solids; performing a first stage precipitation wherein the phosphoric acid generated previously is reacted with a calcium source and water to remove residual fluoride; and performing a second stage precipitation wherein the phosphoric acid generated previously is reacted with a calcium source and water to isolate the product calcium phosphate salt, having a low level of impurities.

The present invention relates to a method of manufacturing lithium hydroxide, which includes adding at least one acid selected from hydrochloric acid, sulfuric acid, and nitric acid into lithium phosphate slurry including a lithium phosphate particle, adding an alkali material to the lithium phosphate slurry including the acid, and converting it into a lithium hydroxide aqueous solution.

The present invention provides for nutrient extraction and recovery devices that use the Donnan Membrane Principle (DMP) to cause spontaneous separation of dissolved ions along electrochemical potential gradients, wherein anions and cations such as H.sub.2PO.sub.4.sup.−, HPO.sub.4.sup.2−, PO.sub.4.sup.3−, Mg.sup.2+, Ca.sup.2+, NH.sub.4.sup.+, and K.sup.+ are moved from manure containing waste streams through cation and anion exchange membranes into a recovery stream thereby precipitating target compounds including but not limited to struvite, potassium struvite and hydroxyapatite.

A silver-doped, nano-porous hydroxyapatite material is provided that can be utilized to capture radioactive iodine, .sup.129I. Methods of using the silver-doped, nano-porous hydroxyapatite material to remove radioactive iodine, and methods of manufacturing the material are also provided.

A silver-doped, nano-porous hydroxyapatite material is provided that can be utilized to capture radioactive iodine, .sup.129I. Methods of using the silver-doped, nano-porous hydroxyapatite material to remove radioactive iodine, and methods of manufacturing the material are also provided.

A calcium phosphate-based core-shell structured material, a method for preparing the same, and an oral care composition using the same are provided. The calcium phosphate-based core-shell structured material includes an amorphous calcium phosphate (ACP) core and a β-tricalcium phosphate (β-TCP) shell covering the core. The method includes a first sintering step and a second sintering step. The first sintering step is to sinter an ACP material at between 700° C. and 800° C. to obtain an α-TCP shell. The second sintering step allows the α-TCP shell to form into the β-TCP shell by sintering at between 800° C. and 900° C. The oral care composition includes a calcium phosphate mixture and an orally receivable carrier. The calcium phosphate mixture includes a powder of the calcium phosphate-based core-shell structured material and a tricalcium phosphate powder mixed in a weight ratio from 3:5 to 3:7.

A calcium phosphate-based core-shell structured material, a method for preparing the same, and an oral care composition using the same are provided. The calcium phosphate-based core-shell structured material includes an amorphous calcium phosphate (ACP) core and a β-tricalcium phosphate (β-TCP) shell covering the core. The method includes a first sintering step and a second sintering step. The first sintering step is to sinter an ACP material at between 700° C. and 800° C. to obtain an α-TCP shell. The second sintering step allows the α-TCP shell to form into the β-TCP shell by sintering at between 800° C. and 900° C. The oral care composition includes a calcium phosphate mixture and an orally receivable carrier. The calcium phosphate mixture includes a powder of the calcium phosphate-based core-shell structured material and a tricalcium phosphate powder mixed in a weight ratio from 3:5 to 3:7.