The rheology of Victorian brown coal slurries: 2. Effect of pH

✍ Scribed by Fedir Woskoboenko; Stanley R. Siemon; Dennis E. Creasy

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 571 KB
• Volume: 68
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(89)90023-9

✦ Synopsis

The effect of pH on the rheological properties of raw Morwell brown coal slurries has been examined using a Couette viscometer and the results were analysed on the basis of the Bingham plastic model. The plastic viscosity and Bingham yield stress behaved independently. It was found that as the pH was reduced from neutral to a value of 2; the plastic viscosity was reduced by factors of 0.5 and 0.08 at volumetric concentrations of0.48 and 0.60 respectively. The Bingham yield stress was found to have a minimum in the neutral region of <: 1 Pa and to increase dramatically by nearly three orders of magnitude to a maximum at the iso-electric point, pH a.25 The maximum yield stresses obtained were 20 and 150 Pa for the two volumetric concentrations used. Earlier results have been re-analysed to allow for this pH effect, and the fact that the raw brown coal slurries have a natural pH which is a function of concentration.