Rigid, water-resistant phosphate ceramic materials and process for preparing them

A process for manufacturing rigid, water resistant phosphate ceramic material, said process comprising the steps of:

• preparing a mixture comprising from about 11 to about 65 parts by weight calculated on an anhydrous basis of at least one metal oxide selected from the group consisting of Al.sub.2 O.sub.3, MgO, CaO, or ZnO or the hydrates thereof and about 100 parts by weight of calcium silicate,
• preparing a reaction solution comprising from about 80 to about 190 parts by weight of a phosphoric acid solution comprising the equivalent of from about 35 to about 75% by weight of phosphorus pentoxide based on the weight of the acid solution, the water of hydration of said metal oxide being included when calculating the phosphorus pentoxide content,
• adjusting the temperature of said reaction solution to a desired value,
• proportionally intermixing said mixture with said reaction solution, and
• placing the resulting intermixed material in a desired configuration and allowing the compounds thereof to interact,
• the temperature of the reaction solution being selected so as to approximately predetermine the point in time at which said intermixed material becomes rigid relative to the point in time at which vaporization of the water occurs.

A process for manufacturing rigid, water resistant phosphate ceramic material, said process comprising the steps of:

• preparing a metal oxide comprising from about 11 to about 65 parts by weight calculated on an anhydrous basis of at least one metal oxide selected from the group consisting of Al.sub.2 O.sub.3, MgO, CaO or ZnO or the hydrates thereof,
• preparing a reaction solution comprising a portion of said metal oxide and from about 80 to about 190 parts by weight of a phosphoric acid solution comprising the equivalent of from about 35 to about 75% by weight of phosphorus pentoxide based on the weight of the acid solution, the water of hydration of said metal oxide being included when calculating the phosphorus pentoxide content,
• preparing a mixture comprising the remainder of said metal oxide and about 100 parts by weight of calcium silicate,
• proportionally intermixing said mixture with said reaction solution, and
• placing the resulting intermixed material in a desired configuration and allowing the components thereof to interact,
• the amount of metal oxide used to prepare the reaction solution being selected so as to approximately predetermine the point in time at which said intermixed material becomes rigid relative to the point in time at which vaporization of the water occurs.

A composition suitable to provide a rigid, water-resistant phosphate ceramic material, said composition comprising:

• from about 11 to about 65 parts by weight calculated on an anhydrous basis of at least one metal oxide selected from the group consisting of Al.sub.2 O.sub.3, MgO, CaO or ZnO or the hydrates 8 thereof;
• from about 80 to about 190 parts by weight of phosphoric acid solution comprising the equivalent of from about 35 to about 75% by weight of phosphorus pentoxide based on the weight of the acid solution, the water of hydration of said metal oxide being included when calculating the phosphorus pentoxide content;
• and
• about 100 parts by weight of calcium silicate.

A rigid, water-resistant phosphate ceramic material obtained by reacting

• (1) from about 11 to about 65 parts by weight calculated on an anhydrous basis of at least one metal oxide selected from the group consisting of Al.sub.2 O.sub.3, MgO, CaO or ZnO or the hydrates thereof;
• (2) from about 80 to about 190 parts by weight of a phosphoric acid solution comprising the equivalent of from about 35 to about 75% by weight of phosphorus pentoxide based on the weight of the acid solution, the water of hydration of said metal oxide being included when calculating the phosphorus pentoxide content;
• and
• (3) about 100 parts by weight of calcium silicate.