pH & Chemical Stability of Expanded Perlite — Compatibility with Industrial Media:
Expanded perlite exhibits a neutral to slightly alkaline pH (6.5–7.5) and is chemically inert in most industrial environments. Its stability makes it suitable for filtration, horticulture, construction, and insulation applications.
pH indicates the acidity or alkalinity of perlite when mixed with water.
Expanded perlite is:
• Neutral to slightly alkaline
• Non reactive
• Stable across a wide pH range
1.1 Surface Chemistry
• Silicate glass structure → chemically inert.
1.2 Leachability
• Minimal ion release under normal conditions.
High quality expanded perlite typically shows pH 6.5–7.5
3.1 Standard Method:
Procedure:
1:5 perlite water mixture Stir for 1 hour Measure with calibrated pH meter
3.2 Factors Affecting pH
• Mineral impurities
• Weathering
• Storage conditions
4.1 Acid Resistance
Stable in most acids except HF.
4.2 Alkali Resistance
Stable in alkaline media.
4.3 Organic Compatibility
Non reactive with organic compounds.
4.4 Thermal Stability
Maintains chemical integrity up to 1,000°C.
5.1 Filtration
Neutral pH ensures chemical purity.
5.2 Horticulture
Ideal root zone pH.
5.3 Construction
Compatible with cementitious systems.
5.4 Insulation
No chemical degradation.
• Weathering
• Hydration
• Mineral impurities
• Glass chemistry
Deposits with low iron and alkali show stable pH.
Q: Does perlite alter soil pH?
No — it is pH neutral.
Q: Can perlite react with chemicals?
Only with HF acid.
Q: Why does pH vary?
Impurities and weathering.
