Dr D.R. Nagaraj (Nag), for his work in developing flotation chemicals, will be inducted into the International Mining Technology Hall of Fame in the Concentration category at the gala awards dinner in Denver on February 20th, during SME Conference week. In a close run judging, he narrowly beat Olivier Guyot, currently Vice President, Technology at Metso, who created the OCS© software, leader in advanced control for mineral processing optimisation. He has also created a series of revolutionary vision (VisioFroth™, VisioRock™) and audio-based (AudioMill™) sensors, and further developed those into next generation sensors.
Flotation chemicals constitute a most powerful tool in enhancing mineral separation performance, affecting overall economic and environmental impacts of the process. Dr D.R. Nagaraj (Nag) has more than 35 years of outstanding and innovative achievements in the design, development and commercialisation of numerous families of novel flotation reagents (collectors, depressants, dispersants, etc.) and in advancing the art and science of flotation agents for sulphide and non-sulphide mineral separations. His seminal 1987 paper titled The chemistry and application of chelating or complexing agents in minerals separations formally introduced the donor-acceptor model, which paved the way for rational design of flotation reagents. During his entire career he has been involved in a bridge building exercise between academic research and practical applications. However, his persistence at requiring knowledge to be useful has made him sought after by both communities. His holistic approach to reagent selection and flotation optimisation is one example of his devising a rational and practical scheme for dealing with real, complex ores. His pioneering work in the use of SIMS surface analytical technique, for determining the disposition of collectors on mineral surfaces started a trend in the academic community and is an example of the high quality work for which he is known.
In addition to devising schemes to optimize chemical usage, Nag has developed and patented many organic and polymeric materials for flotation and toxic metal removal. These include:
- Alkyl and Aryl monothiophosphates as acid circuit sulphide collectors
- Synthetic functionalized polymers as depressants in sulphide flotation
- Alkoxycarbonyl thionocarbamates as collectors for mildly alkaline circuits
- New Collectors for PGMs and gold.
