The high costs associated with wear and chemical corrosion of industrial equipment used in mineral processing are apparent in decreased productivity and increased maintenance. In particular, nozzles used within the mining and industrial sector are exposed to gases or liquids and solutions, which are corrosive and abrasive. The need to counteract these effects led to the development of ceramic nozzles.
Stephen Jackson, Marketing Manager of Multotec Wear Linings, points out that the use of ceramics in harsh environments is not endemic to the industrial sector. “If you consider that NASA uses ceramics to protect the space shuttle from the searing temperatures on re-entry into the Earth’s atmosphere, as well as the fact that ceramics are used in some bullet proof vests, it then makes perfect sense that they are also used in industry.” Multotec Wear Linings has adopted the technology for use in a range of tailor-made high-alumina ceramic nozzles, which offer considerably extended wear life in harsh spraying applications. “We have used these nozzles to replace stainless steel, cast iron and even silicon carbide nozzles,” he continues.
The company has successfully installed its ceramic nozzles in a number of demanding industrial applications. Jackson cites the example of an application where a wet scrubber spray nozzle is used for particulate removal in emissions. “The spraying is undertaken at temperatures of almost 500°C, whereby the emissions are sprayed with either plain water or slurry usually composed of water, limestone and sand. We have had extremely positive feedback from the customer who says that the use of the ceramic nozzles has resulted in cost savings on labour and plant downtime.”
High-alumina ceramics are extremely hard, rated on the Mohs hardness scale at 9, which is just below the hardness of diamonds, at 10. “Ceramic is a stable oxide and not subject to oxide deterioration like most metals. It is also able to withstand high temperatures. Tests show that at extreme temperatures of 1,100°C it is able to retain approximately 50% of its room temperature tensile strength and dimensional stability,” Jackson explains.
Multotec Wear Linings believes that the use of high-alumina ceramic nozzles should not be approached on a one-size-fits-all basis. “We have a highly experienced team that is tasked with undertaking extensive consultation with customers to ensure best fit in each application. They are able to leverage the experience and expertise they have gained on past installations to provide a solution rather than merely a boxed product. Access to a large range of high-specification nozzles in a number of sizes and shapes, results in optimised productivity for customers,” Jackson concludes.