Why iron removal decides kaolin and feldspar grade
Kaolin buyers specify brightness, and the iron-bearing minerals that depress it. Those discolouring minerals concentrate in the fine fraction, so a stage that treats only the coarse stream leaves most of the problem in the product. Feldspar for ceramic and glass is judged the same way: iron-bearing impurities show up as colour and specks after firing. Our article kaolin brightness: what buyers actually specify covers the specification side.
Kaolin and feldspar slurry: wet electromagnetic separation
PTMS wet electromagnetic separators handle slurries and pulps continuously. The material is already dispersed, so particles present their full surface to the magnetic matrix, and the continuous design keeps throughput steady without stopping the plant. Cooling by water or oil keeps coil temperature stable, so the field strength stays consistent through long runs. Piped and tank designs adapt to existing slurry lines. Wet units are configured to your slurry (solids content, particle size distribution, throughput and the brightness target), so there is no fixed catalogue figure; a datasheet is issued with the quotation.
Dispersant ahead of the magnet
PTMS also supplies the dispersants SHMP and STPP for kaolin lines. A dispersant (deflocculant) helps liberate and disperse iron in the slurry so the magnetic separator can capture it more effectively, for higher whiteness. It does not replace the separator: the dispersant prepares the slurry and the magnet removes the iron.
Dried feldspar and quartz powder: dry electromagnetic separation
When feldspar or quartz has already been dried and flows freely, a dry electromagnetic separator removes iron without water and without a drying step afterwards. The current dry-powder models are PT3A160, PT20A600, PT25A600 and PT1000; the PT20A600 is published at 2.5 T, 20 kW maximum coil power, water and oil double cooling, 600 mm magnetic cavity and 2–4 t/h, and datasheets for the other models are issued on request. See the electromagnetic dry separator for quartz and the dry model guide.
| Material | Form in the plant | Separator route |
|---|---|---|
| Kaolin | Slurry | Wet electromagnetic separator, configured to the slurry |
| Feldspar | Slurry or dried powder | Wet electromagnetic separator, or dry electromagnetic separator (PT3A160, PT20A600, PT25A600, PT1000) |
| Quartz / silica sand | Dried sand or powder, or slurry | Dry electromagnetic separator, or wet electromagnetic separator |
What to send
Material (kaolin, feldspar, quartz or silica sand), form (slurry or dried powder), solids content for slurry, particle size distribution, hourly throughput, current iron content, the brightness or Fe target, and your destination port or country. Send 2–5 kg of the material for the free sample test; the test report is issued within 5 days. No iron-reduction figure is quoted without a test.
Next step: send us your material details (or WhatsApp +86 139 2990 7491) and we reply with a matched model and a quotation. Our FAQ states that a test on a sample of your material comes first, and that no iron-reduction figure is quoted without a test.