ABSTRACT Soft rubber linings based on bromobutyl rubber are well known in the market for their high chemical resistance and very low water absorption. This type of rubber linings are produced in an extrusion process (roller head equipment) and formulated as self-vulcanizing systems. The vulcanization takes places under ambient temperature. They are used in flue gas desulphurization plants and also in large ore treatment plants (hydrometallurgical plants) where we find process temperatures up to 105 °C (221 F). The paper presents two on-site application projects in the mining industry. It will be shown, what the typical demands on such corrosion protection systems are, how the application conditions are and which experiences are gained.
INTRODUCTION The standard method for production non-ferrous metals from their ores involves the high temperature smelting of sulfide minerals. This so-called pyrometallurgical process produces stack gases containing SO2, which is an air pollution hazard unless it is recovered as sulfuric acid – the so-called “fatal acid” of the non-ferrous metals industry. By contrast, the hydrometallurgical process, i.e. low temperature processing of ores by leaching methods, offers advantages. When properly managed, environmental impact is much less, and the operations can often use some of the fatal acid produced by an adjacent smelter. While smelter-based metal refineries are very capital intensive, with the need of large capacities to get economy of scale, hydrometallurgical operations have a lower limit for economy of scale. Leaching processes have at first mainly been used on mine wastes and low-grade or secondary ores rather than for primary minerals. Further developments suggest this is all about to change and that before too long leaching processes will be taking the lead in new base metal production capacity, including that based on primary ores too. The first well known hydrometallurgical process that has been used to treat nickel / cobalt laterite ore from Moa Bay, Cuba has been in use since 1959.