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High-Temperature Furnaces

High-Temperature Furnaces

Date posted: December 7, 2017 // Uncategorized

The process of liquefying a normally solid material in order to fashion it into some useful form has been practiced for millennia, albeit without the aid of the modern high-temperature furnaces employed for that purpose today. As the ability to create, to contain, and to sustain the increasing levels of heat needed to, for example, melt metals, gradually improved, so too did the prospects for improvements in the lifestyle of primitive man. Process metallurgy is a science whose evolution began with the discovery of, first gold, in around 6000 BC, and then copper, more than 2000 years later. Because of its relative softness, gold proved to be of little value other than for its decorative qualities, and only with the discovery of copper did some of the more practical uses for metal begin to emerge. Even without the benefit of high-temperature furnaces, the people of that era learned to chip small pieces from larger chunks of the metal and to hammer and grind them, much as their ancestors had done with stone chippings, to fashion arrowheads and similar items. Named cuprum after the island of Cyprus on which it was mined, copper proved to be brittle and easily broken until the discovery, probably by accident, that, when heated, the metal became more durable – a commonly applied process that is known today as annealing. The earliest evidence of copper being smelted was found in the Nile valley and must have been achieved in the closest thing to a high-temperature furnace available at the time, which appears to date from between 4000 BC and 4300 BC. Given that a campfire burns at a temperature of between 600 and 650 °C, more than 100 degrees below that required for the reduction of copper, it is likely the process was first performed in a potter’s kiln, as the temperatures generated in these structures could easily reach 1200 °C. Later, the discovery of tin led to the first alloy in the form of bronze, which later lost popularity with the dawning of the Iron Age. When man learnt to smelt iron, several new uses for the metal soon began to emerge. The appearance of high-temperature furnaces was an event that still lay far in the future and, by the 17th century, only 12 of the 86 metals known today had been discovered. Even during the following 200 years, that figure only grew to 24. Today, however, process metallurgy plays a vital role in many important industries and many of those metals discovered more recently are now used alone, or alloyed with others, to create materials with extraordinary properties. One collection of metallic elements upon which industry has become especially dependent is a group known as the refractory metals. Typified by their exceptionally high melting points, they are the ideal choice for components associated with high-temperature furnaces for use in the smelting of metals or glass. In the latter application, such components include melting crucibles, mandrels and mandrel shafts, various fittings, such as hoppers, fasteners, and radiation shields, as well as glass-melting electrodes. In South Africa, these items and others for use in hot zones and hot isostatic presses are readily available from Labotec Industrial Technologies.