Steel has many applications in the mining industry because it is inexpensive, strong but lightweight, corrosion-resistant, durable, and sustainable. Tools, drill rigs, demolition equipment, grinding media, mining screens, fluidized bed boilers, pumps, heat exchangers, vessels, pipes, tanks, and cathode plates are made of steel because steel is able to withstand harsh and abrasive mine environments. Heavy mining machinery, including mass excavators, bulldozers, shovels, and crushers are made from steel.
Most mine site structural components are built using steel. But structural steel is susceptible to corrosion without expensive protective coating. According to the International Molybdenum Association web site, there is a growing interest in using duplex stainless steels as a building and construction design material because of their unique characteristics: higher strength than carbon steel and a high level of corrosion resistance for the price relative to austenitic (300-series) stainless steels. In many cases stainless steel is cost-effective if the whole life cycle of the installation is considered. The site also describes the use of duplex stainless steel to make wireline cable, used to lower oil- and gas-well tools and measuring equipment downhole. Wireline must be strong, dependable and resistant to the increasingly corrosive conditions encountered in today’s deeper wells. Molybdenum imparts the required corrosion resistance to the stainless steel and nickel alloys used in this application.
Duplex stainless steel is a composite of austenitic and ferritic steels, and typically contains 22-25% chromium and 5% nickel with molybdenum and nitrogen. Duplex steels are both strong and flexible and are also used in the paper, pulp, shipbuilding, and petrochemical industries. Newer duplex grades are being developed for a broader range of applications.
Two technologies that provide the elemental analysis needed to produce high quality stainless steel are X-ray Fluorescence (XRF) and Optical Emission Spectroscopy (OES). Stainless steel is 100% recyclable and therefore a huge amount of stainless steel must be evaluated at the scrap yard. Handheld XRF analyzers bring immense value to scrap metal recyclers because XRF is a highly accurate, nondestructive testing technique that can analyze a metal sample in seconds with little to no need for sample preparation. With a handheld XRF analyzer, stainless steel scrap can be quickly analyzed and sorted according to grade and type. OES is a robust, reliable, and widely used technology for the analysis of metals and alloys in the lab.