Why do nickel smelters need cooling systems in their furnace linings?

In modern nickel smelters, particularly those processing laterite ores, cooling systems within the furnace's refractory lining are essential due to the extreme operating temperatures required.1

These electric furnaces typically operate between 1,360 °C and 1,610 °C (2,480 °F to 2,930 °F). The need for such high temperatures is driven by the high magnesia content found in most laterite ores and the specific liquidus temperature of the resulting furnace products. Because these temperatures are so intense, an extensive system of cooling blocks is necessary to protect the furnace structure and maintain the integrity of the lining against the heat and chemical environment.12