Kaolin buyer FAQ
Answers to the questions overseas buyers ask most about kaolin grades, specs, samples and shipping.
What is kaolin and how is it used?
Kaolin (china clay) is a white clay mineral composed mainly of kaolinite, Al₂Si₂O₅(OH)₄. It is used in ceramics, paper filling and coating, paints, rubber, plastics, FCC catalysts and fiberglass because of its whiteness, fine particle size, chemical inertness and alumina content.
What is the difference between hydrous and calcined kaolin?
Hydrous (washed) kaolin is processed without heating and keeps its combined water (LOI about 13–14 %). Calcined kaolin is heated to roughly 650–1100 °C, removing combined water; it becomes harder, brighter and more oil-absorbent, which suits paints, plastics and cable compounds.
Why does iron (Fe₂O₃) content matter?
Iron-bearing impurities discolour kaolin and lower whiteness and fired whiteness. PTMS kaolin is purified with high-intensity electromagnetic separation — the same technology PTMS builds for mineral processors — to remove weakly magnetic iron and titanium minerals.
Which parameters should I specify for my industry?
Ceramics: chemistry, fired whiteness, fineness. Paper: ISO brightness, % < 2 µm, viscosity, grit. Paint/rubber/plastics: whiteness, D50, oil absorption, residue. FCC catalyst: kaolinite content, low alkalis and iron, fineness. Fiberglass: stable Al₂O₃/SiO₂, low Fe₂O₃ and alkalis. Our Spec Builder pre-fills typical values for each.
Are the values on this website guaranteed specifications?
No. They are typical reference values drawn from public industry sources. Final specifications, test methods and tolerances are agreed with each customer, usually after sample testing.
Do you offer free samples?
Yes — free samples are available on request. Tell us your industry and key parameters via the Spec Builder or WhatsApp.
What packaging options are available?
25 kg bags, 1-tonne jumbo bags (FIBC) and bulk. Palletising and shrink-wrapping can be discussed for container shipments.
How should kaolin be tested on arrival?
Common methods include XRF for chemistry, ISO 2470 for brightness, sedimentation (Sedigraph) or laser diffraction for particle size, wet sieving for 325-mesh residue, Brookfield viscosity for slurries and ISO 787-5 for oil absorption. Agree the method with your supplier, because results differ between methods.
What is your MOQ, price and lead time?
These depend on grade, packaging and destination. Send your requirements through the Spec Builder and our sales team will reply with a quotation.
Can you ship to my port?
Please enter your destination port in the RFQ. We will confirm shipping options and Incoterms (e.g. FOB, CFR, CIF) in the quotation.
Need a sample or a quote?
Free samples available on request. Build your spec in two minutes and send it via WhatsApp or email.