Smelting Furnace Non Destructive Testing and Monitoring

Abstract

Smelting furnaces are structures designed to produce metal from raw ore. Furnaces are constructed and operated in a way to withstand harsh thermal, mechanical, and chemical conditions. Furnaces are lined by refractory bricks or castables to protect the structure against the harsh operational environment. With time, refractory linings in smelting furnaces undergo deterioration and wear. The deterioration is mainly caused by thermal stresses and chemical attacks, resulting in loss of heat-transfer and load-bearing capabilities. Failure of the lining is dangerous and can affect the structural integrity of the furnace. The degree and mechanism of deterioration depends on many different factors. To examine and monitor smelting furnace integrity, a number of non-destructive testing (NDT) techniques have been developed by the Hatch NDT Group. NDT and monitoring of the refractory lining leads to better safety, longer service life of the furnaces, controlled maintenance, and increased production. In addition to our refractory inspection techniques, we have utilized acoustic emission (AE) to monitor furnace and taphole structural integrity, fiber optics to tightly monitor the hot face of furnace tapholes and high frequency radar systems to monitor and control feed levels in the furnace. In this paper, we will discuss and share case studies on these and several other NDT and monitoring systems that we have developed in the past 16 years to inspect and monitor operating metallurgical furnaces.