Patent ID: 8969439
Filing Date: 2015-03-03
Classification: B09B,C04B,C21B,C22B,Y02P

Abstract:
1. A method of agglomerating small particles in a wet feedstock containing the small particles, the method including (i) forming a binder mixture by mixing the wet feedstock with a binder in the form of an aqueous polyvinyl alcohol solution containing polyvinyl alcohol in a proportion of 2% to 15% by weight of the polyvinyl alcohol solution, such that the polyvinyl alcohol is present in the binder mixture in a proportion of 0.2% to 2% by weight of the binder mixture on a dry basis, wherein the aqueous polyvinyl alcohol solution comprises a polyvinyl alcohol that is fully hydrolysed with a degree of hydrolysis of 97 mol% to 99.5 mol%, and (ii) reacting a gelling agent comprising borax in the proportion of 1% to 7% by weight of the polyvinyl alcohol on a dry basis with the polyvinyl alcohol, thereby inducing cohesive gelation of the polyvinyl alcohol and forming a gelled polyvinyl alcohol which envelops at least a portion of the small particles as an integral part thereof, wherein none of the polyvinyl alcohol, the polyvinyl alcohol solution, and the binder mixture, is or has been subjected to a foaming operation during the method, and wherein the gelled polyvinyl alcohol enveloping the small particles is water resistant, having a high degree of water insolubility at room temperature.