Rheological properties and stability of lignite washery tailing suspensions

•Rheological properties and stability of LWTS were studied.•LWTS has good stability and is suitable for long-term storage and transportation.•Rheological properties were studied by rotational viscometer and pipeline system.•The two rheological methods were compared and a rheological model was proposed.•Dispersant NDF has no effect on stability but improves the rheological properties.

The rheological properties and stability of lignite washery tailing suspensions (LWTS) were studied as a special type of coal water slurry (CWS). The properties of LWTS in these aspects are all shown to meet the requirement of a CWS. Two test methods, i.e., a rotational viscometer and a pipeline test system, were used to study the rheological properties of the LWTS and to distinguish between theory and practice. Furthermore, a rheological model of LWTS transfer in the pipeline test system was proposed and proved to be suitable and useful in designing commercial pipeline systems. Moreover, the influence of an anionic dispersant NDF (a co-polymer of methylene naphthalene sulfonate, styrene sulfonate and maleate) on the stability and rheological properties of LWTS was studied. The dispersant NDF proved to have no effect on the stability of the LWTS, while it significantly improved the rheological properties of the LWTS.