The invention provides a high temperature resistant Portland cement slurry and a production method thereof. The high temperature resistant Portland cement slurry comprises the following components by weight: 100 parts of an oil well Portland cement, 60-85 parts of a high temperature reinforcing material, 68-80 parts of fresh water, 1-200 parts of a density adjuster, 0.1-1.5 parts of a suspension stabilizer, 0.8-1.5 parts of a dispersant, 3-4 parts of a fluid loss agent, 0-3 parts of a retarder and 0.2-0.8 part of a defoamer. The high temperature resistant Portland cement slurry has a good sedimentation stability at normal temperature, and develops strength rapidly at a low temperature. The compressive strength is up to 40 MPa or more at a high temperature of 350 C., and the long-term high-temperature compressive strength develops stably without degradation. Therefore, it can meet the requirements for field application in heavy oil thermal recovery wells, reaching the level of Grade G Portland cement for cementing oil and gas wells.

The invention provides a high temperature resistant Portland cement slurry and a production method thereof. The high temperature resistant Portland cement slurry comprises the following components by weight: 100 parts of an oil well Portland cement, 60-85 parts of a high temperature reinforcing material, 68-80 parts of fresh water, 1-200 parts of a density adjuster, 0.1-1.5 parts of a suspension stabilizer, 0.8-1.5 parts of a dispersant, 3-4 parts of a fluid loss agent, 0-3 parts of a retarder and 0.2-0.8 part of a defoamer. The high temperature resistant Portland cement slurry has a good sedimentation stability at normal temperature, and develops strength rapidly at a low temperature. The compressive strength is up to 40 MPa or more at a high temperature of 350 C., and the long-term high-temperature compressive strength develops stably without degradation. Therefore, it can meet the requirements for field application in heavy oil thermal recovery wells, reaching the level of Grade G Portland cement for cementing oil and gas wells.

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 ?m 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 application provides a negative thermal expansion material having excellent dispersibility and packing properties in a positive thermal expansion material. The negative thermal expansion material of the present invention comprises spherical zirconium tungsten phosphate having a BET specific surface area, of 2 m.sup.2/g or smaller. The degree of sphericity is preferably 0.90 or more and 1 or less. Also preferably, the negative thermal expansion material further contains at least Mg and/or V as a subcomponent element. Also preferably, the content of the subcomponent element is 0.1% by mass or more and 3% by mass or less. Also preferably, the average particle size is 1 m or larger and 50 m smaller.

Biomaterials, in particular bone foams, a process for preparing such materials as well as an applicator for applying the biomaterials directly to the patient's application site, and the use of a composition comprising water, a surfactant and a propellant in the preparation of a bone foam for the preparation of a calcium phosphate foam wherein the foam is obtainable by the mixture of at least two phases, a first phase comprising water and optionally a propellant, a second phase comprising one or more sources for calcium and/or phosphate, and wherein the foaming is performed during the mixture of the at least two phases to provide an improved calcium phosphate foam, process for the preparation of a calcium phosphate foam, use of a composition, solid state structure, calcium phosphate cement foam and bone foam applicator.

Biomaterials, in particular bone foams, a process for preparing such materials as well as an applicator for applying the biomaterials directly to the patient's application site, and the use of a composition comprising water, a surfactant and a propellant in the preparation of a bone foam for the preparation of a calcium phosphate foam wherein the foam is obtainable by the mixture of at least two phases, a first phase comprising water and optionally a propellant, a second phase comprising one or more sources for calcium and/or phosphate, and wherein the foaming is performed during the mixture of the at least two phases to provide an improved calcium phosphate foam, process for the preparation of a calcium phosphate foam, use of a composition, solid state structure, calcium phosphate cement foam and bone foam applicator.

Biomaterials, in particular bone foams, a process for preparing such materials as well as an applicator for applying the biomaterials directly to the patient's application site, and the use of a composition comprising water, a surfactant and a propellant in the preparation of a bone foam for the preparation of a calcium phosphate foam wherein the foam is obtainable by the mixture of at least two phases, a first phase comprising water and optionally a propellant, a second phase comprising one or more sources for calcium and/or phosphate, and wherein the foaming is performed during the mixture of the at least two phases to provide an improved calcium phosphate foam, process for the preparation of a calcium phosphate foam, use of a composition, solid state structure, calcium phosphate cement foam and bone foam applicator.

Biomaterials, in particular bone foams, a process for preparing such materials as well as an applicator for applying the biomaterials directly to the patient's application site, and the use of a composition comprising water, a surfactant and a propellant in the preparation of a bone foam for the preparation of a calcium phosphate foam wherein the foam is obtainable by the mixture of at least two phases, a first phase comprising water and optionally a propellant, a second phase comprising one or more sources for calcium and/or phosphate, and wherein the foaming is performed during the mixture of the at least two phases to provide an improved calcium phosphate foam, process for the preparation of a calcium phosphate foam, use of a composition, solid state structure, calcium phosphate cement foam and bone foam applicator.

It is intended to provide an industrially advantageous method for obtaining zirconium tungsten phosphate that is useful as a negative thermal expansion material and exhibits a single phase in X-ray diffraction. The method for producing zirconium tungsten phosphate according to the present invention comprises using a mixture of a tungsten compound and an amorphous compound containing phosphorus and zirconium as a reaction precursor and calcining the reaction precursor. Preferably, the reaction precursor has an infrared absorption peak at least at 950 to 1150 cm.sup.1, and the maximum value of the infrared absorption peak in this range appears at 1030 (20) cm.sup.1.

The present invention relates to the field of foam formation and stabilization, particularly foamed construction materials, such as cement. Disclosed are additives suitable to obtain mineral foams when added to the corresponding starting materials. The invention provides a ready-to-use product in the form of a solid particulate composition comprising hydrophobized particles (1) and catalytically active particles (2) as defined in claim 1. The invention further provides for manufacturing methods of such ready-to-use product.