Industrial grade/Food grade 99% Calcium phosphate CAS:7758-87-4/12167-74-7

What is Tricalciumphosphate? How does it work?

Tricalcium phosphate (TCP) or tribasic calcium phosphate, is a calcium salt of phosphoric acid with the chemical formula Ca3(PO4)2. It is a white crystalline powder, odourless and slightly soluble in water. It is a major inorganic constituent of human bones and teeth (as hydroxyapatite) and is also found naturally in milk and vertebrate bones. In industry it is a flux in ceramic glazes, a major raw material for bone china, a fluxing and clarifying agent for glass, a source of calcium and phosphorus in phosphate fertilisers and animal feed, and a base material for rust-preventive pigments in coatings. In the kitchen, tricalcium phosphate is used to manufacture bone china tableware. In shipyards, it is used in rust-preventive paints. In agricultural supply stores, it is sold as a fertiliser. In water treatment plants, it is used as a defluoridation filter media.

Basic information: chemical formula Ca3(PO4)2 molecular weight 310.18 CAS number 7758-87-4 (EC 231-840-8), β crystal form also has CAS 12167-74-7 Exists in three crystal forms: α, α’ and β (α and α’ are high-temperature stable forms), industrial products are mostly β type Industrial production: reaction of phosphoric acid with calcium hydroxide (quicklime), double decomposition precipitation of soluble phosphate and calcium salt followed by calcination, or by processing phosphate rock; The principal mineral source is natural phosphate rock (apatite, phosphate rock) which is largely produced in Morocco, Israel, Egypt, the Kola Peninsula of Russia and other places.

It is a white powder without smell, slightly soluble in water (very low solubility, about 0.002 g/100 mL) and insoluble in ethanol. Its relative density is about 3.14; its melting point is about 1670℃; the powder has fine particle size, large specific surface area and good flowability. It is a calcium orthophosphate salt, weakly alkaline, which can react with acids to form soluble calcium dihydrogen phosphate, etc. It can be converted to calcium pyrophosphate at high temperatures. It takes part in reactions as a calcium source and flux in high-temperature systems, such as ceramic firing and glass melting. The chemical properties are stable.

From the perspective of its mechanism of action, industrial-grade tricalcium phosphate has many functions, which are related to its high-temperature fluxing properties, dual supply capabilities of calcium and phosphorus, weak alkalinity, moderate hardness and adsorption properties. The mechanisms of action in different applications are:

1.High temperature fluxing mechanism

CaO in tricalcium phosphate acts as a network modifier and fluxing component in high temperature firing/melting systems, which lower the eutectic point and the firing/melting temperature of the system, promote liquid phase formation and increase the density of the green body and the quality of the glaze.

2. Mechanism of supply of calcium and phosphorus nutrition

Tricalcium phosphate provides available phosphorus (P2O5) and calcium (CaO) which are involved in calcium and phosphorus metabolism processes in crops and livestock such as bones, roots and eggshells. It is a nutrient source for agriculture and feed.

3. Passivation and rust prevention mechanism

Phosphate ions chemically interact with the metal surface to form a dense phosphate passivation film that isolates water and oxygen and inhibits the corrosion of steel. This is the basis of the operation of phosphate anti-rust pigments.

4. Mechanics of soft abrasive polishing

Tricalcium phosphate is a medium hardness material with a Mohs hardness (about 5) and is below the damage threshold for most metal substrates. It is a soft abrasive and will remove surface defects without scratching the substrate.

5.Mechanism of defluorination by adsorption

Tricalcium phosphate surface can adsorb fluoride ions in water, ion exchange to generate insoluble fluorapatite-like substances, so as to remove excess fluoride in drinking water.

6. System for inert filling

Tricalcium phosphate is chemically inert, has a high degree of whiteness, a fine particle size and a moderate density. It can be used as a filler to improve the product’s rigidity, surface quality and costs.

To summarise, industrial tricalcium phosphate is a multipurpose ingredient in the building materials and agriculture industries. It has high-temperature fluxing properties and helps in the firing of ceramics and glass. It has a dual supply of calcium and phosphorus and hence helps agricultural feed. It has passivation and adsorption properties and is used in coatings and water treatment. It is involved in the whole chain of building materials, agriculture, chemicals and environmental protection, from bone china tableware to anti-rust paint, from fertiliser to defluorination filter media

What are the uses of industrial-grade Tricalcium Phosphate?

Industrial grade tricalcium phosphate is used in ceramics, glass, agriculture, animal feed, plastics and rubber, coatings, surface treatment, water treatment, refractory materials, etc., as described below:

1.Ceramic glazes and body fluxes (the main use in the ceramics industry)

Application areas: Architectural ceramics, ceramics for sanitary and everyday use.

Products matched: Ceramic tile glazes, sanitary ware glazes, ceramic colourant bases, body strengthening agents, rapid-firing fluxes at low temperature, art ceramic glazes, glazed tile glazes, etc.

Why it works for this purpose: The calcium oxide in tricalcium phosphate acts as a fluxing component during firing, lowering the eutectic point of the glaze, promoting liquid phase formation, improving glaze gloss, whiteness and smoothness and increasing density and strength of the body.

2.Raw materials of bone china (core application for daily-use ceramics)

Application Areas: Bone china products (china made from bone material).

Products matched: bone china tableware (bowls, plates, coffee cups), bone china tea sets, bone china decorative crafts, bone china gifts, high-end hotel and restaurant porcelain, artistic bone china sculpture and so on.

Why it is appropriate for this purpose: The main raw material of bone china is tricalcium phosphate (artificial calcium phosphate). At high temperature it forms a glassy phase with kaolin and feldspar, giving bone china a translucent texture, high whiteness and good mechanical strength. This glassy phase is an integral part in the production of bone china.

3.Agents for fluxing and clarifying glass and enamel (glass industry)

Application Areas: Glass and enamel industry.

Products matched:Corresponding products Flat glass baches Bottle and jar glass Glassware Glass fibre Enamel glaze Enamel base and top glazes Optical glass baches etc.

Why it is suitable for this purpose: In glass melting, tricalcium phosphate supplies calcium oxide as a network modifier, which reduces the melting temperature and viscosity, thus assisting in the clarification and homogenisation, and enhancing the water resistance of the glass. In enamel, it functions as a flux to enhance the levelling and adhesion of the glaze.

4.Phosphate fertilisers and soil conditioners (primary use in agriculture)

Application Areas: Agriculture and fertiliser industry.

Products matched: Raw materials of calcium magnesium phosphate fertiliser, compound fertiliser ingredients, phosphate fertiliser additives, soil conditioner, acid soil improving agent, special fertiliser for fruit trees and field crops, slow release fertiliser coating material, etc.

Why it works for this purpose: Tricalcium phosphate gives available phosphorus (P2O5) and calcium which promotes crop root development, flower and fruit formation and stress resistance. It is slightly alkaline and can neutralise acidic soils. It is commonly used as a source of calcium and phosphorus in phosphate fertiliser systems and soil improvement.

5.Supplements for feed (feed industry branch) Calcium and Phosphorus

Application Areas:Feed industry.

Products matched: Compound feed for livestock and poultry, premixed feed, calcium and phosphorus additives for pig feed, calcium and phosphorus additives for cattle and sheep feed, poultry egg production feed (eggshell formation), aquatic feed, pet food calcium and phosphorus supplements, feed-grade calcium phosphate, etc.

Why it is suitable for this purpose: Tricalcium phosphate offers bioavailable calcium and phosphorus, which are necessary for the maintenance of bone development in livestock and poultry, eggshell formation, and balance of calcium and phosphorus metabolism. In feed, it is a commonly utilised inorganic raw material for calcium and phosphorus supplement.

6.Fillers for plastics and rubbers (polymer materials field)

Application Areas： Plastics and rubber industry.

Products matched:PP filler masterbatch , PE products , PVC product fillers , rubber seal , rubber shoe materials , wire and cable sheath materials , modified plastics reinforcing fillers, etc.

Why it is suitable for this purpose: Tricalcium phosphate is chemically inert, with high whiteness, fine particle size and moderate density. It is used as a filler to improve the stiffness, dimensional stability and surface whiteness of plastic and rubber products and reduce production costs.

7.Coating fillers and rust preventive pigments (coating industry)

Application areas: Industrial coatings, anti-corrosion coatings.

Products matched:include marine anti-rust primers, bridge steel structure anti-corrosion coatings, container coatings, automotive chassis coatings, building steel structure anti-rust paints, phosphate anti-rust pigments, water-based anti-corrosion coatings, etc.

 Why it works for this purpose: The phosphate ions released by tricalcium phosphate react with the steel surface to form a dense passivation film that prevents corrosion from water and oxygen. It is the basic material of environment-friendly phosphate antirust pigments which can replace traditional lead-chromium antirust pigments.

8.Surface treatment field – Polishing and grinding supplies

Application Areas: Metal Processing & Surface Treatment.

Products matched: Metal polishing paste, aluminium and copper soft metal polishing agent, jewellery polishing powder, optical component polishing material, stainless steel surface treatment abrasive, eyeglass lens polishing agent, precision parts polishing media and so on.

Why it is suitable for this purpose:  Tricalcium phosphate is a moderate Mohs hardness, soft abrasive that can remove oxide layers and micro-defects from workpiece surfaces without scratching the substrate, suitable for fine polishing of soft metals, jewellery and optical components.

9.Defluoridator for drinking water (area of water treatment)

Application Areas: Water treatment and purification.

Products matched: Defluoridation filter material for drinking water in high fluoride area, defluoridation water purifier filter cartridge, bone char defluoridating agent, packing material for centralised water supply defluoridation device, industrial fluoride containing wastewater treatment agent, fluoride containing wastewater adsorbent material, etc.

Why it is suitable for this purpose:  Tricalcium phosphate reacts with fluoride ions in the water by adsorption and ion exchange to form insoluble fluorapatite to remove excess fluoride to drinking water standards. It is a common defluoridation material in high fluoride water treatment and purification equipment.

10.Binders of refractory materials (area of refractories)

Application areas： Refractory materials, high temperature industrial domains.

Products matched: Phosphate-bonded refractory castables, monolithic refractories, kiln lining materials, high-temperature furnace repair materials, ceramic kiln furniture, refractory bricks for glass kiln walls etc.

Why it is suitable for this purpose:  At high temperatures, tricalcium phosphate forms a phosphate-bonded phase with the components of the system, improving the bonding strength, thermal shock stability and erosion resistance of the refractory material, which is suitable for lining high-temperature equipment such as kilns and glass melting furnaces.

To summarise, tricalcium phosphate (TCP, Ca3(PO4)2, CAS 7758-87-4) is a versatile material, finding application in building materials and in industrial and agricultural areas. This mineral is used as a fluxing agent in ceramic glazes and body fluxes, raw material for bone china, fluxing and clarifying agent in glass and enamel, phosphate fertiliser and soil conditioner, calcium and phosphorus supplement in feed, plastic and rubber filler, rust-preventive pigment and coating filler, polishing and grinding agent, defluorinization of drinking water, and refractory binder through its high temperature fluxing, calcium and phosphorus nutrient supply, passivating and rust-preventive activity, soft abrasive polishing, adsorption and defluorination, and inert filler mechanisms. The three main uses are for phosphate fertilisers, bone china and ceramic glazes.