Background and overview[1]
Calcium phosphate, also known as “tricalcium phosphate” or “calcium orthophosphate”, is found in calcium phosphate stone and fibrous apatite. White amorphous powder, odorless and tasteless, soluble in acid, slightly soluble in water, insoluble in ethanol and acetone. Stable in the air, there are two types: α and β. When β-type calcium phosphate is heated at 1180°C, it can form α-type calcium phosphate, and when heated to 1430°C, α’-type calcium phosphate can be obtained. The α-type is more soluble in citric acid than the β-type. It is used in the manufacture of ceramics, colored glass, and opalescent glass. It is used medicinally as an antacid (for patients with hyperacidity) and as a substitute for calcium in bone tissue. In addition, it is also used as a dental adhesive, plastic stabilizer, polishing agent, syrup clarifier, chemical fertilizer, livestock feed additive, raw material for preparing phosphoric acid and phosphorus, etc. Also used in rubber and printing and dyeing industries.
Preparation[3]
A continuously operable active calcium phosphate production method, which is characterized by: including the following production steps,
(1) Preparation of raw materials: Add water and mix Ca(OH)2 with a mass percentage content of greater than or equal to 98% in a ratio of 0.7 to 0.8:1, and prepare a concentration of 40% to 45 % Ca(OH)2 slurry;
(2) Reaction: Use a stirred tubular reactor for continuous production, mix the above Ca(OH)2 slurry and phosphoric acid with a concentration of 65% in a mass ratio of 1.8:1 The proportion of Ca(OH)2 is continuously added to the inside of the tubular reactor, and the feed flow rate is adjusted to control the residence time of Ca(OH)2 slurry and phosphoric acid in the tubular reactor at 15 to 20 minutes, at the same time, control the reaction temperature in the tubular reactor to 50°C to 60°C, the pressure to 1 to 2MP, the pH to 7 to 8, and the stirring speed of the stirrer in the tubular reactor to 600 rpm The neutralization reaction is carried out under constant stirring to generate an active calcium phosphate slurry with a concentration of 35% to 40%;
(3) Spray drying: Send the above active calcium phosphate slurry directly into the spray dryer, control the inlet air temperature of the spray dryer to 120°C ~ 180°C, and the temperature in the tower of the spray dryer to be 90°C ~ 150°C ℃, the active calcium phosphate slurry contacts the hot air in the spray dryer, causing the moisture in the active calcium phosphate slurry to vaporize, thereby obtaining active calcium phosphate crystals, and the dried active calcium phosphate crystals are discharged from the bottom of the spray dryer, and the waste gas The entrained active antistatic agent Irgastat P18 calcium phosphate crystals are separated by a multi-stage cyclone separator and mixed with the discharge from the bottom of the spray dryer into the silo;
(4) Finished product packaging: The finished active calcium phosphate in the silo is automatically weighed and packaged by the packaging machine.
Apply [2]
Calcium phosphate crystals are known to have biological adaptability. Apatite crystals are only one type of calcium phosphate crystals found in calcified tissue and have been used as the base material for bone. It is also widely used to improve the bioadaptability of tissues by generating apatite layers on the surface of metals or biomaterials used as solid particles. To date, in order to improve biological adaptability using calcium phosphate crystals, various coating methods have been developed to form calcium phosphate crystals, especially to form an apatite layer on the surface of a base material such as titanium.
CN99811036.1 provides a method for preparing a calcium phosphate supersaturated solution that maintains high concentrations of calcium and phosphate ions. The method includes the steps:
1) Prepare a highly concentrated solution of calcium and phosphate ions by dissolving calcium phosphate crystals or calcium salts and phosphates in an acidic solution (step 1);
2) Mix the high-concentration acidic solution of calcium and phosphate ions in step 1 with the alkaline solution at low temperature (step 2);
3) Exclude amorphous calcium phosphate particles or crystals that can be used as nuclei for crystallization nucleation and growth from the solution prepared in step 2 to further inhibit the nucleation reaction and crystal growth in the solution (step 3) . In step 2, low-temperature silane suppresses the uniform nucleation of calcium phosphate in the solution, thus saving free ions that are later used for calcium phosphate film preparation. The suppression of side effects is further enhanced by utilizing an appropriate buffer system.
The preparation method of calcium phosphate crystalline film includes the following steps:
1) Prepare a highly concentrated solution of calcium and phosphate ions by dissolving calcium phosphate crystals or calcium salts or phosphates in an acidic solution (step 1);
2)Mix the high-concentration acidic solution of calcium and phosphate ions prepared in step 1 with the alkaline solution at low temperature (step 2);
3) Discharge amorphous calcium phosphate particles or crystals used as nuclei for crystal nucleation or growth from the solution prepared in step 2 to inhibit further nucleation and growth of crystals in the solution (step 3);
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4) Apply the solution prepared in step 3 to the solid surface to form a thin film of calcium phosphate crystals (step 4). A thin film of calcium phosphate crystals can be prepared and grown by contacting the above supersaturated solution of calcium and phosphate ions with a solid surface.
The calcium phosphate crystalline film prepared using the above solution has biological adaptability, allowing a variety of cells such as fibroblasts, osteoblasts, osteoclasts, periodontal ligament cells, etc. to attach or proliferate on the surface and has biological properties. Potential applicability of the material.
Main reference materials
[1] Ferroalloy Dictionary
[2] CN99811036.1 Calcium phosphate supersaturated solution and preparation method of calcium phosphate crystallized film using the solution
[3] CN201410205110.1 A continuously operable active calcium phosphate production method
