Publication: Optimising the use of raw materials in Metal processing – the best doctoral thesis of the year 2021 offers solutions

The Foundation for Research of Natural Resources in Finland granted the award for the best doctoral thesis in 2021 to Lassi Klemettinen, who earned his Doctor of Technology degree from the School of Chemical Engineering at Aalto University. The doctoral thesis provided new data and improved accuracy concerning the distribution of rare earth metals and noble metals in the PRINCIPAL production process of base metals, FLASH SMELTING.

The award was presented on 19 May 2022 in Helsinki at the seminar entitled “Natural Resources in Tomorrow’s Solutions”, which was arranged in the honour of the 70th anniversary of the Foundation for Research of Natural Resources in Finland.


“Several recycled raw materials are already included in flash smelting processes. In the future, their share will further increase”, says Lassi Klemettinen. His doctoral thesis work provides tools for optimising the use of both virginal and recycled raw materials in flash smelting.

Professor emeritus Pekka Taskinen, who served as thesis advisor for Klemettinen, refers to the history of the flash smelting process:

“After the second World War, Finland suffered from a serious lack of energy and materials. The nation was highly motivated to develop a new energy-saving method for metal production”, Taskinen explains.

Flash smelting can be used to produce various metals, such as copper and nickel. Today, more than half of the copper in the world is produced by means of flash smelting. In Finland, the method is in use at the copper and nickel smelting plant in Harjavalta.

Many of the smelters have, however, been optimised to handle ORE concentrates, which means that more research is needed to better understand the effects of introducing recycled raw materials into the process. In his thesis work, Doctor of Technology Lassi Klemettinen investigated the behaviour of several trace elements present in secondary raw materials (Ir, Mo, Pb, Re, Sn, Te, Ga, In, La, Nd, Li, Co, Mn) in copper smelting experiments.

Professor Ari Jokilaakso, the supervisor of Klemettinen’s thesis, points out that no comparison data was found in the literature for the behaviour of, for example, gallium, indium, lithium and lanthanum in the flash smelting process. “For manganese, the new data indicates clearly that it cannot be recovered in the current copper smelting processes”, Jokilaakso says.

The improved accuracy and reliability of the data is due to the adoption of new, direct phase-by-phase analysis techniques and their application to metallurgical samples. The results can be directly applied to industrial metallurgical processes in order to optimise the simultaneous recovery of as many metals as possible.


The Foundation grants the best thesis award annually

The Foundation for Research of Natural Resources in Finland granted the €10,000 award for the second time. A total of 13 doctoral theses approved at universities in Finland in 2021 were nominated as candidates for the award. The annually granted award supports the Foundation’s activities as a funding agency for research of natural resources in Finland.

“We want to encourage young researchers to engage in the research related to the sustainable use of Finland’s natural resources”, says Professor Pekka A. Nurmi, Chair of the Board of Directors for the Foundation for Research of Natural Resources in Finland.

The Foundation considered that Lassi Klemettinen’s doctoral thesis Behaviour of trace elements in copper smelting processes – LA-ICP-MS as a tool for sample characterisation advances the utilisation of Finnish mineral reserves and use of recycled raw materials.

According to Nurmi, the thesis investigated the behaviour of elements required, for example, in electrification, and their distribution and analysis in flash smelting, which is the leading industrial process. Although it is necessary to advance the utilisation of renewable natural resources, Nurmi points out that the demand for non-renewable metals is also increasing in, for example, the green transition technologies.

In industrial-scale smelting processes, an improvement of a few percent in the yield of valuable metals may translate to a profit of millions of euros. The share of metallurgical industry of the value of Finnish exports amounts to 12–15 percent, so it is a significant field of industry.

Resource-efficient operations, outstanding analysis methods, circular economy and state-of-the-art technologies contribute to the sustainable utilisation of natural resources. The development of these aspects calls for research, innovations and breakthroughs related to natural resources, and all these are promoted by the Foundation for Research of Natural Resources in Finland through grant funding.


More information:

Professor Pekka A. Nurmi, Chair of the Board of Directors, Foundation for Research of Natural Resources in Finland, tel. +358 40 504 5236.

D.Sc.(Tech.) Lassi Klemettinen, Postdoctoral Researcher, Aalto University, lassi.klemettinen@aalto.fi, tel. +358 44 214 9569