silica making process

Here’s an article on the silica manufacturing process in English:

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Silica Manufacturing Process: From Raw Material to Industrial Applications

Silica (silicon dioxide, SiO₂) is a versatile material widely used in industries such as electronics, construction, cosmetics, and chemicals. The production process varies depending on the desired form (amorphous or crystalline) and purity. Below are the key methods for manufacturing silica.

1. Production of Amorphous Silica
Amorphous silica lacks a defined crystalline structure and is produced through chemical or thermal processes.

# a) Precipitated Silica
- Raw Materials: Sodium silicate (water glass) and sulfuric/ hydrochloric acid.
- Process:
1. Sodium silicate is dissolved in water to form a solution.
2. Acid is added to precipitate silica gel.
3. The gel is washed, filtered, and dried to remove impurities.
4. The dried product is milled into fine powder.
- Applications: Tire reinforcement, toothpaste abrasives, food additives.

# b) Fumed Silica (Pyrogenic Silica)
- Raw Material: Silicon tetrachloride (SiCl₄).
- Process:
1. SiCl₄ is vaporized and burned in a hydrogen-oxygen flame (~1,800°C).
2. High heat triggers hydrolysis:
\[ \text{SiCl}_4 + 2\text{H}_2\text{O} \rightarrow \text{SiO}_2 + 4\text{HCl} \]
3. The resulting fine silica particles are collected.
- Applications: Thickeners in paints, adhesives, and pharmaceuticals.

# c) Gel Silica
- Made by acidifying sodium silicate to form a hydrogel, which is then purified and dried.
- Used in catalysts and desiccants.

2. Production of Crystalline Silica (Quartz Processing)
Natural quartz undergoes purification for high-purity applications like semiconductors.

# a) Mining & Beneficiation
- Quartz ore is crushed, washed, and magnetically separated to remove impurities (e.g., iron).

# b) Chemical Purification
- Treated with hot acids (HCl/HF) to dissolve metal contaminants.
- Further refined via calcination or chlorination for ultra-high purity (>99.999%).

3. Key Industrial Grades
| Type | Purity | Primary Use |
|------------------|-----------|--------------------------------------|