Pengfu Tan's Story
Dr Pengfu Tan's resume is peppered with achievements of international significance, testament to his tireless efforts to advance metallurgical practice. He has designed metallurgical process optimisation models and software used in smelters across the globe, penned 83 international journal and conference papers and authored three metallurgical books. In his time at Xstrata Copper's Mount Isa smelter alone, Dr Tan has designed and initiated several projects to minimise copper loss in Rotary Holding Furnace (RHF) slag, improvements worth more than $12 million per year; developed and implemented a thermodynamic model to simulate the converter process, solving the high-frequency converter foam-over issue which had remained unsolved for decades; and achieved an overall smelter recovery of more than 98 per cent, a free metal gain worth approximately $30 million annually.
But ironically, by far the biggest challenge he has faced in his career had nothing to do with increasing copper yield or finding a cost-efficient way to extract precious metals from tailings. It was trying to work out why our smelter's primary furnace bricks were disappearing so fast.
"Despite what we learn at university, in practice, chemical engineering isn't the cut-and-dry science we like to think it is. The mining industry continues to present unique challenges.
I was born in the mineral-rich Hunan Province in China's central-south, and early on I began to understand the vital role the region's resources played in the world. This burgeoning curiosity developed into a passion for metallurgical engineering that would see me complete two doctorate degrees on the subject. It's what drives my determination for finding solutions to smelting's universal challenges.
I spent the early years of my career as a research academic in China, Finland and then Germany, before stepping into the role of Principal Engineer at Glencore's Portovesme zinc-lead smelter in Sardinia, Italy. When Mount Isa Mines was acquired by Xstrata in 2003, I was invited to take up the Principal Metallurgist position at the Copper Smelter in Mount Isa. It was an experience, waving goodbye to my island home in the Mediterranean, bound for a bustling mining town in the heart of Queensland's iconic outback.
In late 2010, our ISASMELT™ furnace experienced an accelerated brick wear rate of 260 millimetres for that year. Re-bricking the primary furnace requires a huge capital outlay for us – it's by far our biggest expense - and at that rate we would have had to push the next scheduled re-bricking project forward significantly, which means a complete shutdown of the smelter for 30 days. The stakes were very high.
Through exhaustive testing and trials, we found that by improving the temperature, slag chemistry, draft and burner fire rate controls and by establishing an optimised smelting temperature target, we were able to decrease the brick wear rate of the ISASMELT™ furnace to only five millimetres for the entire 2011 campaign - almost a 96 per cent reduction, and the slowest brick wear rate for all licensed ISASMELT™ furnaces in the world. The improvement has resulted in a directly attributable capital expense saving of $5 million, thanks to the reduced need for major re-bricking works. It has also amounted to an operational increase equivalent to $3 million by minimising production time lost.
We're now striving to achieve a four-year campaign life for the current ISASMELT™ furnace. In years past, ISASMELT™ campaigns have been as short as nine months.
This was a great outcome for us, and a brilliant investigative opportunity for our team. Smelting will always require experienced metallurgists to trouble-shoot and improve performance, and this project in particular highlighted that to our younger metallurgists, so what a great learning experience it was. After all, getting the best performance out of the ore we pull out of the ground is what mining is all about.
The best part of my job is the continuous improvement aspect, solving problems and always looking for new ways to do what we do better."