How to choose a mineral powder grade

Most grade-selection problems come from starting with a number instead of a job. Start with what the powder has to do, then pick the properties that deliver it. This page gives the order of decisions we use on every inquiry.

1. Start from the application

In plastics and masterbatch, talc raises stiffness and heat deflection; calcium carbonate is the low-cost bright filler; both need good dispersion. In coatings, whiteness, brightness and oil absorption dominate. In paper, opacity and retention matter. In rubber, reinforcement and low abrasion protect equipment.

Tell us the application and we will shortlist two or three grades instead of quoting a catalogue.

2. Pick the properties that move the result

Whiteness and brightness drive appearance in coatings, PVC and paper. Oil absorption affects formulation cost and viscosity — lower is usually better. Mohs hardness matters where the powder contacts screws, dies and calender rolls; talc (Mohs 1) is the softest and most equipment-friendly.

For exterior or wet systems, moisture and impurity limits (Fe2O3, SiO2 depending on product) protect colour and stability.

3. Decide fineness last

Fineness is the final tuning knob, not the first. Once the product and the key properties are set, choose the coarsest mesh that still meets performance — see our mesh size guide for the mapping and the common ranges by product.

If two adjacent mesh sizes both look viable, sample both; the process difference is usually larger than the number implies.

4. Consider surface treatment

For polymers, a coupling agent (silane, titanate or stearate) improves compatibility and mechanicals. Specify the polymer and we will recommend whether treatment pays off for your part.

Surface treatment is optional and quoted per grade; it is not assumed by default.