The nickel and cobalt industries play an important role in the global economy and serve as essential components in various industrial processes and technologies. These metals are known for their unique properties and versatile applications, making them indispensable in industries ranging from stainless steel manufacturing to advanced battery technologies. As important players in the transition to sustainable energy solutions and technological advances, nickel and cobalt have received a lot of attention in recent years.
The production of nickel and cobalt from primary sources involves enrichment and hydrometallurgical and pyrometallurgical processing. Nickel is recovered from lateritic oxides, either as ferronickel from saprolite ores or
as an intermediate mixed sulfide or hydroxides from limonite ores. Intermediate products are refined into high-purity nickel. Cobalt in nickel ores is recovered during refining. Recycling of nickel and cobalt also takes place to a significant extent through the reuse of alloy materials.
Among other processing methods, the High-Pressure Acid Leach (HPAL) process is a hydrometallurgical technique for the extraction of valuable metals, particularly nickel and cobalt, from laterite ores. Laterite ores are a type of ore that is rich in iron and low in sulphur, but also contains significant amounts of nickel and cobalt. The HPAL process addresses the challenges posed by low nickel content and high impurity levels in these ores and has as a major benefit the ability to quickly leach nickel and cobalt from laterite ores.
For the processing of laterite nickel and cobalt in HPAL plants, it is necessary to heat a slurry flow. In most plants direct heating with steam injection is used to heat the slurry. The disadvantages of using direct heat transfer by employing direct steam injection is that the fresh slurry feed is diluted with the condensates.
There has always been a drive to apply indirect heating in HPAL plants because of the benefits of indirect heating in comparison with direct heating:
- Increase autoclave production capacity;
- Reduced acid consumption;
- Reduced neutralising agent consumption;
- Recovery of demineralised condensate and process condensate.
However, while indirect heating methods can be effective in some situations, they come with issues and challenges in the context of HPAL, such as severe fouling of the heat exchangers and the related issues like reduced heat transfer, shutdowns and maintenance.
With the KLAREN self-cleaning heat exchanger technology, most of these issues and challenges can be overcome.
