Calcium silicate (Ca2SiO4) is a mineral compound that’s used in construction materials, insulation, and fireproofing. It’s made by combining calcium oxide and silica. Calcium silicate provides heat insulation and is resistant to fire.
| IUPAC Name | Calcium silicate |
| Molecular Formula | Ca2SiO4 |
| CAS Number | 1344-95-2 |
| Synonyms | Silicic acid, calcium salt (2:1); Calcium metasilicate; Calcium silicon oxide; Calcium orthosilicate |
| InChI | InChI=1S/Ca.2O.Si/q+2;2*-1; |
Calcium Silicate Properties
Calcium Silicate Molar Mass
Ca2SiO4 has a molar mass of 172.237 g/mol. This value is calculated by adding the atomic masses of calcium, silicon, and oxygen, which are 40.078 g/mol, 28.085 g/mol, and 15.999 g/mol, respectively. The molar mass is important in determining the amount of Ca2SiO4 needed in chemical reactions or for preparing solutions.
Calcium Silicate Boiling Point
Ca2SiO4 does not have a definite boiling point because it decomposes before reaching its boiling point. When Ca2SiO4 is heated, it undergoes a series of chemical reactions that lead to the release of water and the formation of calcium oxide and silica. The decomposition temperature of Ca2SiO4 depends on the specific type and composition of the compound.
Calcium Silicate Melting Point
Ca2SiO4 has a melting point of 2130°C. At this temperature, Ca2SiO4 transforms from a solid to a liquid state. The melting point of Ca2SiO4 is relatively high, which makes it suitable for high-temperature applications such as refractory materials, insulation, and fireproofing.
Calcium Silicate Density g/mL
The density of Ca2SiO4 varies depending on the specific type and composition of the compound. The density of Ca2SiO4 ranges from 2.2 to 2.8 g/mL. The high density of Ca2SiO4 makes it useful for applications where weight is a concern. For example, it is used as a lightweight aggregate in concrete.
Calcium Silicate Molecular Weight
The molecular weight of Ca2SiO4 is 172.237 g/mol. This value is determined by adding the atomic weights of calcium, silicon, and oxygen to the compound. The molecular weight of Ca2SiO4 is used in various calculations, such as determining the concentration of solutions or the amount of compound needed in chemical reactions.
Calcium Silicate Structure
Ca2SiO4 has a crystalline structure that can vary depending on the specific type and composition of the compound. The most common crystalline structure is a monoclinic crystal system. The crystal structure of Ca2SiO4 provides it with certain properties such as high strength, thermal stability, and chemical resistance.
Calcium Silicate Formula
The chemical formula of calcium silicate is Ca2SiO4. This formula represents the ratio of calcium, silicon, and oxygen in the compound. The formula of calcium silicate is important in determining its properties and for use in various applications such as cement, insulation, and fireproofing.
| Appearance | White Powder |
| Specific Gravity | 2.2 – 2.8 g/cm³ |
| Color | White |
| Odor | Odorless |
| Molar Mass | 172.237 g/mol |
| Density | 2.2 – 2.8 g/cm³ |
| Melting Point | 2130°C |
| Boiling Point | Decomposes before boiling |
| Flash Point | Not Applicable |
| Water Solubility | Insoluble |
| Solubility | Insoluble in water, soluble in acids |
| Vapour Pressure | Not Applicable |
| Vapour Density | Not Applicable |
| pKa | Not Applicable |
| pH | 7.0 – 9.0 |
Calcium Silicate Safety and Hazards
Ca2SiO4 is generally considered safe for use in various applications, including construction materials, insulation, and food additives. However, prolonged or excessive inhalation of Ca2SiO4 dust may irritate the respiratory system. Skin and eye contact with Ca2SiO4 may also irritate. While Ca2SiO4 is not considered a hazardous substance, it is important to handle it with care and follow safety guidelines when working with the material. Personal protective equipment such as gloves, safety goggles, and respiratory protection should be worn when handling Ca2SiO4 to minimize potential health risks.
| Hazard Symbols | Not Applicable |
| Safety Description | Not a hazardous substance |
| UN IDs | Not Applicable |
| HS Code | 6810.19 |
| Hazard Class | Not Applicable |
| Packing Group | Not Applicable |
| Toxicity | Low toxicity; may cause respiratory and skin irritation with prolonged or excessive exposure |
Calcium Silicate Synthesis Methods
A variety of methods can synthesize Ca2SiO4.
In one method, Calcium oxide (CaO) reacts with silica (SiO2) to produce a mixture of calcium silicates. The high-temperature furnace allows for the synthesis of Ca2SiO4. The mixture includes Ca2SiO4 and Ca3SiO5. Further processing and grinding of the mixture produce different grades of Ca2SiO4 powder.
Another method involves the reaction between calcium hydroxide (Ca(OH)2) and silica in an autoclave at high pressure and temperature. This process produces a purer form of Ca2SiO4, known as wollastonite (CaSiO3), which has a wide range of applications, including as a filler in plastics and coatings.
Other synthesis methods for Ca2SiO4 include the reaction between calcium chloride (CaCl2) and sodium silicate (Na2SiO3) to produce Ca2SiO4 hydrate (CSH), which is the main binding agent in Portland cement.
Various reagents and methods allow for the synthesis of Ca2SiO4 by precipitating it from a solution of calcium and silicate ions.
Calcium Silicate Uses
Ca2SiO4 has a wide range of applications due to its unique properties, such as high-temperature resistance, low thermal conductivity, and excellent fire resistance. Here are some common uses of Ca2SiO4:
- Insulation: Used as an insulation material in high-temperature applications such as furnace linings, boiler insulation, and steam pipes. Its low thermal conductivity makes it an effective insulator in these environments.
- Construction materials: Used in various construction materials such as bricks, tiles, and cement. Its high-temperature resistance and fire resistance make it an ideal material for use in fire-rated walls and ceilings.
- Food additives: Used as an anti-caking agent in food products such as powdered sugar and salt. Its ability to absorb moisture and prevent clumping makes it a popular choice for food manufacturers.
- Pharmaceuticals: Used as an excipient in pharmaceuticals, where it serves as a binder, disintegrant, and flow agent.
- Cosmetics: Used in cosmetics as a bulking agent and absorbent. It helps to improve the texture and feel of products such as face powders and foundations.
- Other uses: Also used in the production of ceramics, refractory materials, and as a filler in rubber and plastics.
Questions:
Q: How to remove calcium silicate from a pool?
A: To remove Ca2SiO4 from a pool, use a pool tile cleaner or a solution of muriatic acid and water. Apply the cleaner or solution to the affected area and scrub with a stiff-bristled brush. Rinse thoroughly with water after cleaning.
Q: How to make calcium silicate refractory at home?
A: Making Ca2SiO4 refractory at home is not recommended due to the high temperatures and specialized equipment required. It is best to purchase pre-made Ca2SiO4 refractory products from a reputable supplier.
Q: Calcium silicate compounds hydrate to form what two compounds?
A: Ca2SiO4 compounds hydrate to form Ca2SiO4 hydrate (CSH) and calcium hydroxide (Ca(OH)2). These compounds play important roles in the formation and strength of concrete and other cementitious materials.