Comparative study of the rheological properties of kaolins from two deposits occurring nearby in Portugal, one residual and the other sedimentary

• Type: Article in International Scientific Journal
• Date: 1999

Authors

Carames, M (Author) Other; Bobos, I (Author) Other; Gomes, C (Author) Other

Journal

The Journal is awaiting validation by the Administrative Services.

Title: Mineralogica et Petrographica Acta

Vol. 42

Pages: 57-69

ISSN: 0540-1437

Indexing

ISI Web of Knowledge

Scopus - 0 Citations

Other information

Authenticus ID: P-007-8QW

Abstract (EN): Kaolins from two nearby (ca.10 km apart) deposits located at the north - western littoral of Portugal, were studied for their mineralogy, chemistry, morphology and rheology. Both deposits are genetically related, one of residual type and the other of sedimentary type. Three size fractions: < 38 ¿m, < 10 ¿m and < 2 ¿m were analysed, in order to assess the relationships between texture, mineralogy, genesis and rheological properties. Kaolinite is the main mineral component in all size fractions of both residual and sedimentary kaolins. It exhibits particles having regular shape and good structural order. Particle size distribution in both kaolins is characterised by notorious differences. Residual kaolin has higher particle mean size and better particle size classification than sedimentary kaolin in which particles are grouped in two populations. In average, kaolinite crystals in residual kaolin exhibit better regular shape, higher mean size and better structural order than kaolinite in sedimentary kaolin. CEC values determined for residual and sedimentary kaolin are: 4.23 meq/100g and 9.30 meq/100g, respectively. Also, BET values are 19.18 m2/g for residual kaolin and 20.35 m2/g for sedimentary kaolin. The viscosity of sedimentary kaolin is considerably higher than the viscosity of residual kaolin, regardless of the addition of NaOH (0.1N), due to its smaller grain size. ¿-potential measurements carried out on both residual and sedimentary kaolin yield differ significantly, corresponding the lower values to residual kaolin.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13