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.

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.

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 method of making porous ceramic granules is provided. The method comprises heating pore-forming agent particles to a temperature above a glass transition temperature for the pore-forming agent particles; contacting the heated pore-forming agent particles with a ceramic material to form a mixture of pore-forming agent particles and ceramic material; heating the mixture to remove the pore-forming agent particles from the mixture to form a porous ceramic material; and micronizing the porous ceramic material to obtain the porous ceramic granules, wherein the porous ceramic granules have an average diameter from about 50 μm to 800 μm. The porous ceramic granules are also disclosed.

Octacalcium phosphate according an embodiment is prepared by a process including 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, heating the calcium phosphate solution of which the initial pH is controlled to a temperature ranging from 60° C. to 90° C., adding a heterogeneous seed comprising at least one selected from among octacalcium phosphate and dicalcium phosphate dihydrate to the heated calcium phosphate solution, after adding the heterogeneous seed, adjusting a terminal pH by controlling the pH of the heated calcium phosphate solution to which the heterogeneous seed is added to a range from 5 to 6.

Methods and compositions are provided for treatment of an apatite-based resin from which retained solutes have been eluted by an elution buffer that contains an alkali metal salt with solutions of calcium ion, phosphate ion, and hydroxide separately from any sample loading and elution buffers. The treatment solutions restore the resin, reversing the deterioration that is caused by the alkali metal salt in the elution buffer.

A method of producing a product inorganic compound including: immersing a raw material inorganic compound having a volume of 10.sup.−13 m.sup.3 or more in an electrolyte aqueous solution or an electrolyte suspension; exchanging anions in the raw material inorganic compound with anions in the electrolyte aqueous solution or the electrolyte suspension; cations in the raw material inorganic compound are exchanged with cations in the electrolyte aqueous solution or the electrolyte suspension; or including a component (that excludes water, hydrogen, and oxygen) in the electrolyte aqueous solution or the electrolyte suspension not included in the raw material inorganic compound in the raw material inorganic compound; and obtaining a product inorganic compound having a volume of 10.sup.−13 m.sup.3 or more from the raw material inorganic compound.

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 calcium-deficient silicate-substituted calcium phosphate apatite composition comprises an apatite phase having a Ca/P molar ratio of from greater than 2.15 to 2.30, and a Ca/(P+Si) molar ratio of from 1.45 to 1.55. A method of producing a calcium-deficient silicate-substituted calcium phosphate apatite composition comprises contacting a silicate-substituted calcium phosphate apatite starting material with an acidic solution to produce the calcium-deficient silicate-substituted calcium phosphate apatite composition. The starting material comprises an apatite phase and up to 15 wt % total of a phase or phases other than the apatite phase, and has a Ca/P molar ratio of from 2.3 to 2.6, and a Ca/(P+Si) molar ratio of from 1.56 to 1.66, and the calcium-deficient silicate-substituted calcium phosphate apatite composition comprises an apatite phase having a Ca/P molar ratio lower than the Ca/P ratio of the starting material apatite phase.

A method of producing a product inorganic compound including: immersing a raw material inorganic compound having a volume of 10.sup.−13 m.sup.3 or more in an electrolyte aqueous solution or an electrolyte suspension; exchanging anions in the raw material inorganic compound with anions in the electrolyte aqueous solution or the electrolyte suspension; cations in the raw material inorganic compound are exchanged with cations in the electrolyte aqueous solution or the electrolyte suspension; or including a component (that excludes water, hydrogen, and oxygen) in the electrolyte aqueous solution or the electrolyte suspension not included in the raw material inorganic compound in the raw material inorganic compound; and obtaining a product inorganic compound having a volume of 10.sup.−13 m.sup.3 or more from the raw material inorganic compound.