Effect of sodium hexametaphosphate and ageing on the rheological behaviour of kaolin dispersions

摘要: Concentrated dispersions (35% v, v) of ceramic grade kaolin dispersed with sodium hexametaphosphate (NaHMP) were prepared at three different experimental conditions: in distilled water 30 and 60 °C, a 5*10 −3 M Ca(NO3)2·4H2O solution, °C. The kept constant temperatures for ageing times (2, 4, 6, 18, 24, 48 h). After each period they submitted to rheological measurements centrifuged measure the concentration HMP − ion supernatant solution by ICP. Measurements electrophoretic mobility containing KCl as background electrolyte also performed both presence absence NaHMP. results allow better understanding roles played calcium ions They shed light on deflocculating mechanism Correlations between parameters chemical properties could be established. © 2005 Elsevier B.V. All rights reserved.