Abstract: Dicalcium phosphate dihydrate containing a sufficient amount of trimagnesium phosphate and/or tetrasodium pyrophosphate to inhibit spontaneous hydrolysis and/or decomposition of the dicalcium phosphate dihydrate is widely used as a dental polishing agent with and without added fluoride. Now it has been found that dicalcium phosphate dihydrate containing a sufficient amount of pyrophosphate to provide hydrolytic stability to the dicalcium phosphate can have improved fluoride stability when about 0.1 weight percent to about 5 weight percent of trimagnesium phosphate, and about 0.1 weight percent to about 3 weight percent of at least one pharmaceutically acceptable condensed phosphate salt is added to the formulation. In the preferred embodiment less than 2 percent sodium tripolyphosphate provides satisfactory results.

Abstract: Disclosed is a method of preparing a calcium phosphate catalyst, which comprises reacting a calcium salt with a phosphoric acid salt in aqueous ammonia, separating the precipitate resulting from the reaction mixture thus obtained, suitably shaping said precipitate, drying it, and subjecting it to heat treatment within a temperature range of 450.degree. to 600.degree. C. in the presence of steam mixed with at least one of the components selected from the group consisting of an inert gas, air, phosphoric an acid, aldehyde, an oxygen-containing heterocyclic compound, an alcohol, and a diene hydrocarbon.The reaction of calcium salts with phosphoric acid salts in aqueous ammonia is effected with the starting reactants taken in the molar ratio of 1.5:1 if no phosphoric acid treatment is used, or with the starting reactants in a molar ratio within the range of 1.5:1 to 5.0:1 if the reaction mixture is treated with a phosphoric acid solution to a pH of from 5.0 to 7.0.

Abstract: Dicalcium phosphate dihydrate containing a sufficient amount of trimagnesium phosphate and/or tetrasodium pyrophosphate to inhibit spontaneous hydrolysis and/or decomposition of the dicalcium phosphate dihydrate is widely used as a dental polishing agent with and without added fluoride. Now it has been found that dicalcium phosphate dihydrate containing a sufficient amount of pyrophosphate to provide hydrolytic stability to the dicalcium phosphate can have improved soluble fluoride stability when at least 0.1 weight percent of trimagnesium phosphate and a pharmaceutically acceptable polyphosphate salt are each added to the formulation. In the preferred embodiment, less than 2 percent pentasodium tripolyphosphate provides satisfactory results.

Abstract: A process is disclosed for preparation of an amorphous polyaluminum sulfate composition of the formulaAl(OH).sub.x (SO.sub.4).sub.y (H.sub.2 PO.sub.4).sub.z (H.sub.2 O).sub.wwhereinx is about 0.75 to 1.5y is about 0.7 to 1.07z is about 0 to 0.2w is about 2.0 to 4.2with the proviso that the sum x+2y+z is 3. Water is withdrawn from a fairly fresh polyaluminum sulfate solution having the formulaAl(OH).sub.x' (SO.sub.4).sub.y' (H.sub.2 PO.sub.4).sub.z' (H.sub.2 O).sub.w'whereinx' is about 0.75 to 1.5y' is about 0.7 to 1.07z' is about 0 to 0.2w' is about 18 to 65with the proviso that the sum x'+2y'+z' is 3. The amorphous composition is useful for reconstitution with water to prepare a coagulant solution.

Abstract: A process for producing zinc phosphate comprising treatment of zinc oxide with phosphoric acid in an aqueous medium at a temperature ranging from 70.degree. to 80.degree. in the presence of metallic zinc taken in an amount of from 1 to 10% by weight of zinc oxide, followed by separation of the resulting residue of zinc phosphate. It is possible to introduce zinc oxide and metallic zinc into the treatment process in a composition of zinc-containing wastes resulting from the production of formaldehyde sodium sulphoxylate or sodium hydrosulphite, or 2,2-hydroxy-5-methylphenylbenzotriazole. The yield of zinc phosphate is as high as 98%. The process of this invention makes it possible to produce zinc phosphate ensuring high protective and physico-mechanical properties of paint coatings based on synthetic binders. Thus, no signs of corrosion are observed on the coating based on epoxy resin and zinc phosphate produced by the process of this invention after tests for 6 months at temperatures of 20.degree. and 60.

Abstract: A novel, polycrystalline whitlockite ceramic in either pore-free or porous form, processes for the preparation thereof and methods of using the same as biological implant materials are disclosed.

Abstract: Animal feed grade phosphates such as mono-calcium phosphate, di-calcium phosphate or mixtures thereof are produced by direct reaction between phosphoric acid and Ca-containing materials. A finely ground, preheated calcium carbonate suspension is brought to react with a suitable quantity of preheated phosphoric acid by introducing the reactants into a short, tubular reaction zone, open at one end, whereby development of gas and intensive mixing of the reactants in the reaction zone take place. The gas formed by the reaction expels or ejects the foaming reaction mixture from the tube-like reaction zone, the reaction being substantially completed while the individual particles of the mixture are freely suspended in air or gas, whereafter the reacted mixture is collected in the form of a free-flowing granulate having improved handling properties, without any further quenching treatment of the granules.

Abstract: Process for preparing dicalcium phosphate dihydrate with displacement 0.1 - 5% of the calcium by divalent metal ion.

Abstract: A process for stabilizing anhydrous dibasic calcium phosphate against reaction with fluorine ions comprising treating an aqueous suspension of anhydrous dibasic calcium phosphate at a pH of from 5 to 10 with a cyclic aminophosphonic acid of the formula ##STR1## WHEREIN N IS AN INTEGER FROM 1 TO 3, OR A WATER-SOLUBLE SALT THEREOF, IN AN AMOUNT OF FROM 0.01% TO 5% BY WEIGHT WITH REFERENCE TO THE ANHYDROUS DIBASIC CALCIUM PHOSPHATE; AS WELL AS TOOTH CLEANING PREPARATIONS CONTAINING THE STABILIZED ANHYDROUS DIBASIC CALCIUM PHOSPHATE.

Abstract: A process for stabilizing dibasic calcium phosphate dihydrate against hydrolysis comprising treating an aqueous suspension of dibasic calcium phosphate dihydrate at a pH of from 5 to 10 with a cyclic aminophosphonic acid of the formula ##STR1## wherein n is an integer from 1 to 3, or a water-soluble salt thereof, in an amount of from 0.01 to 5% by weight with reference to the dibasic calcium phosphate dihydrate; as well as tooth cleaning preparations containing the stabilized dibasic calcium phosphate dihydrate.

Abstract: A process for stabilizing dibasic calcium phosphate dihydrate against hydrolysis comprising treating an aqueous suspension of dibasic calcium phosphate dihydrate at a pH of from 5 to 10 with an azacycloalkane-2,2-diphosphonic acid of the formula ##STR1## WHEREIN N IS AN INTEGER FROM 3 TO 5, OR A WATER-SOLUBLE SALT THEREOF, IN AN AMOUNT OF FROM 0.01% TO 5% BY WEIGHT WITH REFERENCE TO THE DIBASIC CALCIUM PHOSPHATE DIHYDRATE; AS WELL AS TOOTH CLEANING PREPARATIONS CONTAINING THE STABILIZED DIBASIC CALCIUM PHOSPHATE DIHYDRATE.

Abstract: A process for stabilizing dibasic calcium phosphate dihydrate against hydrolysis comprising treating an aqueous suspension of dibasic calcium phosphate dihydrate at a pH of from 5 to 10 with 3-amino-1-hydroxypropane-1,1-diphosphonic acid, or a water-soluble salt thereof, in an amount of from 0.01 to 5% by weight with reference to the dibasic calcium phosphate dihydrate; as well as tooth cleaning preparations containing the stabilized dibasic calcium phosphate dihydrate.

Abstract: A method of preparing dicalcium phosphate from phosphate rock wherein the rock is treated with a mixture of water, carbonyl, and sulfur dioxide. Solids are separated from the liquid phase. The solid phase consists of a mixture of gangue, and calcium .alpha.-hydroxysulfonate. Carbonyl and part of the sulfur dioxide are recovered from the solid by low temperature thermal decomposition. Dicalcium phosphate is precipitated from the liquid phase by partial distilling of SO.sub.2. All carbonyl is recovered for recycle.

Abstract: A process for stabilizing anhydrous dibasic calcium phosphate against reaction with fluorine ions comprising treating an aqueous suspension of anhydrous dibasic calcium phosphate at a pH of from 5 to 10 with 3-amino-1-hydroxypropane-1,1-diphosphonic acid, or a water-soluble salt thereof, in an amount of from 0.01% to 5% by weight with reference to the anhydrous dibasic calcium phosphate; as well as tooth cleaning preparations containing the stabilized anhydrous dibasic calcium phosphate.

Abstract: A process for stabilizing anhydrous dibasic calcium phosphate against reaction with fluorine ions comprising treating an aqueous suspension of anhydrous dibasic calcium phosphate at a pH of from 5 to 10 with an azacycloalkane-2,2-diphosphonic acid of the formula ##STR1## wherein n is an integer from 3 to 5, or a water-soluble salt thereof, in an amount of from 0.01% to 5% by weight with reference to the anhydrous dibasic calcium phosphate; as well as tooth cleaning preparation containing the stabilized anhydrous dibasic calcium phosphate.RELATED ARTAnhydrous dibasic calcium phosphate having the formula CaHPO.sub.4 is a polishing substance frequently utilized in tooth cleaning preparations as, for example, toothpastes and powders. For this purpose it may be used alone or in admixture with other polishing substances as, for example, silica gel or plastics cleaning substances.

Abstract: Process for producing triple superphosphate by reacting dilute phosphoric acid and lime, limestone or dolomite and granulating the resultant product.

Abstract: Crystalline AlH.sub.3 (PO.sub.4).sub.2 .multidot.3H.sub.2 O is obtained from an aqueous solution of aluminum phosphate containing a molar ratio of Al.sub.2 O.sub.3 :P.sub.2 O.sub.5 of from 1:2 to 1:6 and an organic solvent that is miscible with water. Crystallization is enhanced by the addition of AlH.sub.3 (PO.sub.4).sub.2 .multidot.3H.sub.2 O seed crystals to the aqueous solution. The product is useful in reducing the setting time of hydraulic binders.

Abstract: Precursors for the preparation of phosphate glasses are provided. Controlled preparation of the precursors in precise stoichiometric proportions enable the preparation of glasses which are stable and possess superior optical properties of an order similar to optical glasses. Suitable precursors within the contemplation of the invention are those having the formula:M(H.sub.2 PO.sub.4).sub.nwherein M is a metal ion selected from the group consisting of Al, Zn, Cd, Fe, Sn, Mn, Pb, Ni, Co, Ga, and In and the alkaline earth metals Be, Mg, Ca, Sr and Ba and wherein n has a value of 2 or 3 depending on whether M is a divalent or trivalent ion. Mixtures of these compounds may be employed, the admixture being made prior to melting stoichiometric equivalent precursor mixture. In addition, any combination of precursors containing divalent and/or trivalent cations may be selected.

Abstract: A new synthesis is disclosed which produces synthetic crystalline hydroxyapatite. The process comprises reacting anhydrous trisodium phosphate wih calcium chloride in a formamide/water solution. Good yields of hydroxyapatite are obtained quickly, simply, and at low temperatures.

Abstract: An aqueous slurry of CaHPO.sub.4.2H.sub.2 O in a 5-20 Wt% concentration is prepared by the use of the phosphate dihydrate obtained by reaction of NaNH.sub.4 HPO.sub.4.4H.sub.2 O with CaCl.sub.2 in water. After adjustment of the pH of the slurry to 4.5-5.5, the slurry is rapidly heated to 85.degree.-97.degree. C by contact with steam to convert the dihydrate to the anhydride, which is suitable for use in the preparation of fluorescent materials due to its high purity, platy and square crystal shape and uniform particle size.

Abstract: A process is described for producing high purity phosphoric acid from phosphate rock including low grade phosphate rock material such as Idaho phosphate ores having P.sub.2 O.sub.5 contents as low as 20 percent. Finely divided phosphate rock, sulfuric acid, phosphoric acid and water are charged to a mixing zone in proportions such that the pH of the resultant slurry is in the range 0.8 to 1.2 and the calcium ion content of the liquid phase of the slurry is in the range 3 to 4 percent by weight. Sulfuric acid is charged to the mixing zone in a quantity sufficient to convert the nonphosphate calcium compounds in the rock to calcium sulfate plus the quantity required to convert the contained calcium phosphate to monocalcium phosphate, phosphoric acidis charged to the mixing zone in quantities such that it is, on a molar basis, from about 1.2 to about 1.4 times the P.sub.2 O.sub.

Abstract: Zirconium phosphate is made by reacting a zirconium salt with phosphoric acid or a phosphate in a liquid medium, the zirconium salt being insoluble in water. A granular product may be obtained having a grain size controlled by that of the salt. The product may be used as an ion-exchange material.

Abstract: Crystalline AlH.sub.3 (PO.sub.4).sub.2.3H.sub.2 O is obtained from an aqueous solution of aluminum phosphate containing a molar ratio of Al.sub.2 O.sub.3 :P.sub.2 O.sub.5 of from 1:2 to 1:6 and an organic solvent that is miscible with water. The product is useful in diminishing the setting time of hydraulic binders.

Abstract: Phosphate values of high purity and concentration may be efficiently recovered from a wide range of phosphatic-mineral-containing materials including as-mined phosphate ore by leaching such ore with a dilute aqueous mixture of sulfuric and hydrochloric or nitric acid, and precipitating phosphate values as dicalcium phosphate. This product, which is already suitable for use in animal feed and agricultural fertilizer, can also be readily converted to the many other agricultural and industrial phosphate products without costly purification operations or means of control of pollution to the surrounding environment.

Abstract: A solid source consisting essentially of high purity aluminum metaphosphate, Al(PO.sub.3).sub.3 is used for introducing elemental phosphorus into P-type silicon chips or wafers of semi-conductor grade. The aluminum metaphosphate functions as a source for the controlled release of P.sub.2 O.sub.5 vapors which are directed to the desired face of the silicon wafer. The reverse side of the silicon wafer receives little or no phosphorus and consequently retains its character as P-type silicon.

Abstract: A method for preparing a hydrated monocalcium phosphate, with reduced caking tendencies and quick carbon dioxide release, from a monocalcium phosphate composition having a loss on ignition between about 14 and less than 17% by admixing water with the monocalcium phosphate and permitting the water and monocalcium phosphate to remain in contact for a sufficient length of time to form a hydrated monocalcium phosphate composition having a loss on ignition between 17 and 21.5%. The product is dried to a free moisture content of less than about 1% if the free moisture content is above this level.

Abstract: The invention provides condensed aluminum phosphates which contain P.sub.2 O.sub.5 and Al.sub.2 O.sub.3 in a molar ratio equal to or greater than 1.5:1, are X-ray amorphous and have an apparent density between 50 and 200 grams/liter.They are made by spray-drying an aluminum orthophosphate solution or suspension containing P.sub.2 O.sub.5 and Al.sub.2 O.sub.3 in the molar ratio desired in the final product, in a spray tower at temperatures higher thana 250.degree.C to effect direct transformation into condensed aluminum phosphates.

Abstract: When titanium phosphate is used as a white pigment to an article of which surface comprises polyolefin composition, the article is remarkably whitened.

Abstract: Calcium-sodium-phosphates suitable for animal feed use are produced by heating a granulated mixture containing 1.75 to 2.25 moles calcium oxide and 1.25 to 0.75 moles sodium oxide per mole of P.sub.2 O.sub.5 for at least 10 minutes to between 600.degree. to 1,000.degree.C, while being subjected to vigorous movement and cooling to room temperature.

Abstract: a method for treating asbestos to reduce its hemolytic activity is disclosed. The method comprises depositing on at least a portion of the asbestos a sufficient amount of a material consisting essentially of at least one water-insoluble metal orthophosphate to reduce the hemolytic activity of the asbestos. The resulting fibrous asbestos product consists essentially of asbestos fibers having at least one water-insoluble metal orthophosphate deposited thereon. Suitable metals include magnesium, calcium, barium, titanium (III), titanium (IV), chromium, manganese, iron (II), iron (III), cobalt, nickel, zirconium, silver, aluminum, zinc, cadmium, tin (II), tin (IV), and lead.