Characterization and Rheological Improvement of Boyolali White Bentonite with Soda Ash and Carboxy Methyl Cellulose

Abstract

The main objective of this study was to evaluate the effect of soda ash (SA) and carboxy methyl cellulose (CMC) on the rheological of white bentonite collected from Boyolali, Indonesia (BWB). The first work was the determination of BWB composition with XRF and the study on the effect of SA on the swelling index. The second step was to study adding SA and CMC on viscosity at 600 and 300 rpm. Another rheological parameter (yield point to plastic viscosity ratio, μP/μV) was determined based on the viscosity data. The results showed that the BWB sample tended to be categorized as Ca-bentonite with a calcium oxide content of 0.70 wt.% and contained montmorillonite, quartz, and pyrophyllite. SA and CMC in BWB increased the interlayer space of the montmorillonite. The addition of 14 wt.% SA to the BWB sample showed the maximum swelling index of 10 mL/2 g. The optimal formula meeting API 13A specifications is BWB sample of 81.23 wt.%, soda ash 14 % (w/w), and CMC 4.77 wt.%. This product results in the viscosity at a reading of 600 rpm of 30 cP and the μP/μV ratio of 1.0. Therefore, the product is potential as a candidate material for drilling mud.