Effects of Chemical Additives on Rheological Properties of Dry Ground Ore - a Comparative Study

Abstract

It is well documented that chemical additives (grinding aid "GA") during grinding can increase mill throughput, reduce water and energy consumption, narrow the particle size distribution of products, and improve material flowability. These advantages have been linked to their effects on the rheology, although there is a gap in understanding GA effectiveness mechanism on the flow properties. The present study aims to fill this gap using different GAs (Zalta™ GR20-587, Zalta™ VM1122, and sodium hydroxide) through batch grinding experiments of magnetite ore and addressing the mechanisms of their effects on the rheology by an FT4 Powder Rheometer as a unique system. Experimental results showed that GA improved grinding efficiency (energy consumption and product fineness), which were well-correlated with basic flow energy, specific energy, aerated basic flow energy, and aerated energy. Moreover, the rheometry measurement showed strong linear correlations between basic flow energy, specific energy, and the resulting work index when GAs was considered for grinding, which confirmed the effect of GA on ground particles' flowability. Zalta™ VM1122, a polysaccharide-based grinding aid, showed the best performance with 38.8% reduction of basic flow energy, 20.4% reduction of specific energy, 24.6% reduction of aerated basic flow energy, and 38.3% reduction of aerated energy. It also showed the strongest correlation between the grinding parameters and flow parameters (r > 0.93). The present investigation shows a strong indication that the predominant mechanism of GAs is based on the alteration of rheological properties and identify Zalta™ VM1122 as the best GA.

Influence of milling methods on the flow properties of ivory teff flour

“…SE represents the interparticle interactions due to cohesive forces, which are highly dependent on particle shape, texture, and size. Lower SE means fewer interparticle forces and lower degree of cohesion (Chipakwe, Hulme‐Smith, Karlkvist, Rosenkranz, & Chelgani, 2021; Gnagne, Petit, Gaiani, Scher, & Amani, 2017; Nan, Ghadiri, & Wang, 2017). No significant difference was observed among the three flours in terms of SE.…”

Beneficial effects of a polysaccharide-based grinding aid on magnetite flotation: a green approach

“…In the cement industry, the use of grinding aids (GAs) has been examined as a promising alternative to address these issues 3 , 4 . Chemical additives or GAs would be considered as any substance (less than 0.25 wt.%) added to the mill to reduce energy consumption 5 – 7 . GAs have been mostly examined in the cement industry and are still not widely practiced in mineral beneficiation plants.…”

“…Previous studies demonstrated the benefits of polysaccharide-based GA (PGA) as a green chemical additive in improving mineral grinding performance 10 and material rheology 5 . However, the high cost and purported effects on downstream processes as a result of the potential synergistic interaction of the GAs and flotation reagents limit their applications.…”

Exploring the effect of a polyacrylic acid-based grinding aid on magnetite-quartz flotation separation

“…The positive effect of grinding aids on improving product fineness has been observed in the literature [10,[41][42][43]. The improvement in fineness points to better grinding due to improved material flowability resulting from the reduction in agglomeration [5,6,41,44,45]. In terms of uniformity, which generally measures PSD, the introduction of AAG results in a narrow PSD width (lower number uniformity).…”