Selection of Ultra-fine Grinding Equipment for Chemical Raw Materials: Corrosion Resistance and Stability Considerations

1. Special Challenges in Grinding Chemical Raw Materials

1. Strong corrosivity

   Organic acids, inorganic salts, pigments, dyes, pesticide intermediates, chlorine/sulfur compounds, etc., cause serious corrosion to metal parts.

2. Easy oxidation / flammable and explosive

   Some powders burn or explode when exposed to air or high temperatures, requiring inert protection and explosion-proof structures.

3. Hygroscopic and adhesive

   Easy to agglomerate and stick to the wall after grinding, leading to blockage and reduced output.

4. High hygiene / high purity requirements

   Metal contamination and dust leakage are strictly prohibited; requires dead-angle-free, easy-to-clean, and non-precipitating design.

5. Continuous production demand

   Equipment must run stably with low failure rate, simple maintenance, and long service life.

2. Core Selection Factor 1: Corrosion Resistance — Material is the First Lifeline

1. Comparison of Common Corrosion-resistant Materials

• 304 Stainless Steel

  Application: weakly corrosive, neutral, conventional chemical powders

  Features: general-purpose, moderate cost, average rust resistance

• 316L Stainless Steel

  Application: weak acid, weak alkali, salt-containing, chlorine-containing materials

  Features: resistant to pitting and damp heat, mainstream choice in chemical industry

• 2205 Duplex Steel

  Application: moderate corrosion + high wear occasions

  Features: high strength, better corrosion resistance than 316L

• Hastelloy / Titanium Alloy

  Application: strong acid, strong oxidation, high-temperature corrosive environments

  Features: ultimate corrosion protection, relatively high cost

• Engineering Plastic / PTFE Lining

  Application: strong acid and alkali, materials where metal ion contamination is prohibited

  Features: non-conductive, non-corrosive, non-polluting

• Wear-resistant Ceramics (Alumina / Zirconia)

  Application: materials with both high hardness and corrosion

  Features: ultra-wear-resistant, no metal precipitation, high chemical stability

2. Selection Recommendations

• General chemical powders → 316L Stainless Steel
• Strong acid and alkali → PTFE Lining / Hastelloy
• High purity, anti-metal contamination → Ceramic Lining + Ceramic Classifier Wheel
• High wear + corrosion → Ceramic + Duplex Steel Combination

3. Core Selection Factor 2: Operational Stability — Ensuring Continuous Production

1. Key Structures Ensuring Stability

1. Reliable sealing system
   • Multi-stage shaft seals and air seals to prevent dust leakage and material entry into the bearing housing
2. Stable temperature control
   • Low-temperature / temperature-controlled design to avoid melting, denaturation, and explosion caused by temperature rise
3. Anti-blocking design
   • Smooth inner walls, air sweeping devices, reasonable flow field to reduce wall adhesion
4. Shock absorption and low noise
   • Stable operation, suitable for long-term 24-hour continuous work
5. Easy disassembly and cleaning
   • Quick-release structure greatly reduces time for material change, cleaning, and maintenance

2. Direct Benefits of Stability

• Equipment life increased by 2–5 times
• Maintenance costs reduced by more than 50%
• More uniform particle size and higher product qualification rate
• Significantly lower risk of safety accidents

4. Recommended Grinding Solutions for Different Chemical Materials

1. Pigments, Dyes, Color Powders

• Characteristics: easy adhesion, easy contamination, pure color required
• Recommendation: 316L / Ceramic-lined Jet Mill / Mechanical Ultra-fine Grinding Machine
• Key points: anti-wall adhesion, no metal contamination, easy cleaning

2. Pesticide Intermediates, API Chemicals

• Characteristics: corrosive, high purity requirements
• Recommendation: 316L / Ceramic Inert-protected Ultra-fine Grinding System
• Key points: GMP hygiene, corrosion protection, closed and dust-free

3. Inorganic Salts, Chemical Fillers

• Characteristics: high hardness, high wear, certain corrosiveness
• Recommendation: Ceramic-lined Jet Mill + Wear-resistant Classifier Wheel
• Key points: wear resistance, long service life, high stability

4. Resins, Plastics, Rubber Additives

• Characteristics: heat-sensitive, adhesive, easy to soften
• Recommendation: Cryogenic Ultra-fine Grinding Equipment
• Key points: temperature control, anti-adhesion, anti-melting

5. Flammable and Explosive Powders

• Characteristics: flammable, explosive, explosion-proof required
• Recommendation: Inert Gas Closed-loop Grinding System
• Key points: nitrogen protection, explosion-proof motor, explosion-proof certification, anti-static

5. 5-step Final Selection Method for Chemical Ultra-fine Grinding Equipment

1. Confirm material corrosivity: strong acid / weak acid / neutral / strong oxidation
2. Confirm explosion-proof and anti-oxidation needs: whether nitrogen protection is required
3. Confirm purity requirements: whether trace metal precipitation is allowed
4. Confirm capacity and particle size: mesh/μm, output kg/h
5. Confirm working conditions: continuous production, humidity, temperature, on-site layout

6. Summary

• Corrosion resistance: determines equipment life and whether material is contaminated.
• Stability: determines whether safe and continuous long-term production is possible.