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  • Plate Water Absorption as a...
    McDonald, Jacob; Kawatra, S. Komar

    Mineral processing and extractive metallurgy review, 07/2017, Letnik: 38, Številka: 4
    Journal Article

    Plate water absorption has been traditionally used to assess the binding ability of bentonite clay binders for iron ore concentrate pelletization. Until 1997, there was an accepted test by ASTM, but due to inconstant data this method was withdrawn. This value, however, is still used by some pelletization operations to gauge the efficacy of their bentonite. This test procedure has only been investigated on inorganic binders and never organic binders. This paper seeks to confidently prove that PWA can be used to accurately determine the efficacy of starch binders both alone and in conjunction with bentonite. The role of bentonite as a binder for iron ore concentrate is not only to hold agglomerates together during high temperature operations. But during pelletization it can also mitigate many times its own weight in water. This water absorption capacity aids in retarding the growth rate of pellets, as faster growing pellets tend to be weaker. The value of this water absorption, known as plate water absorption (PWA), is used as a metric to determine the strength and quality of the resulting pellets by industrial pelletizing facilities. As new low silica binders seek to replace bentonite, they too must take on the role of moisture mitigation. This study has shown that starches with lower water absorption capacities tend to have lower compressive strengths. As the water absorption capacity increases so too does the compressive strength. When using only starch, higher absorption capacities lead to lower compressive strengths of pellets exposed to elevated temperatures. When bentonite is used in conjunction with starch, higher water absorption mixtures do exhibit an increase in strength when heated.