Rheological characterization of concentrated jarosite waste suspensions using Couette & tube rheometry techniques

• Rheological behaviour of concentrated jarosite suspension was evaluated.
• Both Couette & tube rheometry techniques were employed for the purpose.
• Flow behaviour of the slurry was characterized by power law model.
• Wall slip and entrance corrections were applied to the tube rheometry data.
• True flow curve of the slurry was then obtained for pressure drop prediction.

Hydraulic disposal of jarosite wastes at high solid concentrations may be considered as a safe mode of disposal from environmental and economic points of view. The rheological and pipe flow characteristics of jarosite waste slurry samples in mass concentration ranging from 40 to 60% have been investigated. The rheological experiments performed on the samples using both Couette and tube rheometry techniques indicated non-Newtonian pseudo plastic behaviour and were well described by a power law model in the studied range of concentrations. The pressure drop for the suspension was predicted from the estimated true flow curve data in a novel type tube viscometer after incorporating necessary wall slip and entrance-effect corrections. The predictive capabilities of the pressure drop model in pipe flow velocity range of 0.8–1.8 m/s dramatically improved when compared with the pipeline experimental data in a 100 mm nominal bore pipe. Therefore, it is quite imperative to adopt suitable rheometry techniques to avoid discrepancy in predicting the true flow behaviour of the concentrated jarosite waste suspensions for economic hydraulic disposal.

Comparative evaluation of predicted pressure drop data using rheometry techniques with actual pipeline experimental data in a 100 mm NB pipe for concentrated jarosite–water suspension, Cw = 54.6%.Figure optionsDownload as PowerPoint slide