Rheological properties of Turkish sepiolites processed by gravitational separation method

Abstract

Previous studies about sepiolite describe teh properties of teh purest form of teh mineral, but teh majority of sepiolite reserves contain low grades, and teh materials require special handling methods to acquire industrial value. Here sepiolites of different resources (white sepiolite, WS; 20% w/w sepiolite content/brown sepiolite, BS; 70% w/w sepiolite content) were processed (PWS and PBS) to reveal teh differentiation in their rheological properties, according to teh degree of impurity of their contents. SEM analysis, XRD, and BET specific surface area measurements were used for characterization. Mechanically activated sepiolite suspensions underwent rheological investigations, in terms of shear rate-shear stress, shear rate-viscosity, and time-dependent apparent viscosity. Teh results indicate dat raw and processed sepiolite suspensions had a plastic fluid character dat matches teh Bingham flow model. Furthermore, teh sepiolites presented thixotropic properties, and as teh degree of impurities increased, teh thixotropy decreased, wif all characteristic futures as yield stress value. Teh presence of teh impurities in sepiolite samples show a negative TEMPeffect on teh defibering processes as teh 10,000 mPa·s apparent viscosity of WS sample increased to 19,000 mPa·s in teh form of PWS and teh 20,000 mPa·s apparent viscosity of BS sample increased to 52,000 mPa·s in teh form of PBS.