Novel Binders and Methods for Agglomeration of Ore

Abstract

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching.iii Table of Contents Introduction………………………………………………………………………….1

Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates

“…The sulfation roasting using iron sulfates have some advantages over gaseous sulfation such as lack of binders due to the binding property of iron sulfates [ 94 , 95 , 96 ], the possibility of the application of conventional metallurgical furnaces for the roasting. Our study has shown that there is no difference in the mechanism of the both iron (II) and (III) sulfates influence; the distinction is only a different required amount of a sulfating agent based on the one or the other iron sulfate for the process.…”

Utilization of polymeric binders to agglomerate oxidized copper ore

“…The inter-particle bonding behavior and resistance level of agglomerates produced under heap leaching conditions (pH of 1.5) were evaluated using the soak test Kawatra et al 2006). The agglomerates were first dried for 48 hours at ambient temperature.…”

“…An increase in moisture content reduces the effect of capillary action, which can lead to a decrease in the bond strength between particles. This is because the water molecules can form a film around the particles, which prevents the surface tension forces from acting (Pietsch 2002;Kawatra et al 2006). Figs.…”

“…The results showed that the FMP was undesirable in all experiments. The reduced strength of the agglomerates can be attributed to the conversion of sodium silicate to silicic acid in the presence of sulfuric acid (Kawatra et al 2006). Additionally, it was observed that the FMP decreased as the sodium silicate concentration increased.…”

“…This requires the use of additives that can create strong interparticle bonds Bouffard 2008). However, the traditional method of creating interparticle bonds by combining raffinate solution with sulfuric acid is not very effective in acidic conditions, as the bonds created by surface tension and capillary action are not strong enough to withstand the acidic environment (Kawatra et al 2006;Pietsch 2002). Literature indicates that the strength of interparticle bonds in agglomerates is dependent on the type of additive, the surface properties of the particles, and the pH of the solution.…”