Energy-efficient production of manganese-iron alloys through pre-processing: Thermal pre-treatment using solar energy
In the PreMa research project, scientists are investigating different approaches to CO2 reduction for the production process of manganese-ferroalloys. In previous projects, researchers from the Norwegian research organisation SINTEF found that thermal pre-treatment of the manganese ore reduces CO2 emissions and total energy consumption in the production of manganese ferroalloys by about 20 percent each. For the pre-treatment, the researchers are investigating different innovative technologies, such as the recycling of the CO-rich off-gas emitted by the manganese arc furnace; regenerative and fossil carbon, as well as concentrating high-temperature solar technology.
Researchers at the DLR Institute of Solar Research are now developing a plant with thermal preheating technology using solar heat for manganese ore pre-processing. By investigating the pre-production of manganese ores, PreMa is providing answers to the need of energy-intensive industries to adapt their production processes and operations to an increasingly sustainable but highly fluctuating energy supply.
In recent years, global demand for manganese alloys has shown an upward trend, reaching a level of about 22 million tonnes in 2018. The production of manganese alloys requires a lot of electricity and heat, which are currently generated almost entirely by burning fossil fuels. To reduce this emissions footprint, new technologies are needed that allow renewable energy to be used as an energy source for the process. They help to reduce CO2 emissions in the production of manganese-ferroalloys and make the process more sustainable and flexible, and thus more competitive, through the energy sources used.
Producing manganese-ferroalloys using solar energy
Pre-treatment of manganese ores increases energy flexibility and energy efficiency, improves the raw material utilization of fine ore and reduces CO2 emissions in the production of manganese alloys.
The main concept of PreMa is to reduce the overall energy consumption and CO2 emissions in the production of manganese alloys, exploring technologies that also increase energy flexibility and enable the use of sustainable energy sources. The researchers want to expand the current production process of manganese alloys in the submerged arc furnace (SAF) one step before by the thermal pre-treatment of the manganese ore. Alternative energy sources such as bio-carbon, CO-rich off-gas and concentrating high-temperature solar technology are being tested for their suitability as heat suppliers for this purpose.
As part of the project, the researchers are developing various pre-treatment technologies and demonstrating them in conjunction with different energy sources.
More energy-efficient production processes, reduced costs and improved process reliability
The PreMa research project improves the raw material utilization of fine ore. The pre-treatment of manganese ores
The scientists are also designing the technology to be flexible enough to be easily adapted to the specific needs and production routes of individual manganese producers, the main difference being the use of different ores.
Partial replacement of fossil fuels with sustainable energy is expected to reduce operating costs and the amount of CO2 tax required in Europe. It is expected that the integration of the novel PreMa pre-treatment technologies into the processes currently used by smelters will lead to the following results:
Researchers at the DLR Institute of Solar Research are developing a new heat exchanger technology that can use heat from the sun to thermally pre-reduce manganese ores for the sustainable production of manganese ferroalloys.
In a heliostat field, numerous mirrors concentrate the incident solar rays onto a particle receiver on the solar tower. Here, ceramic particles are heated up to 1000 degrees Celsius and trickle downwards through the newly developed particle-air direct-contact trickle-flow heat exchanger (TFHX). Simultaneously, air enters the TFHX from below and flows countercurrently to the trickling particles upwards and heats up to 800 degrees. The hot air generated in this way can now be further used for the thermal pre-treatment of the manganese ore. A suitable plant in which the manganese ore is pre-heated with the hot air generated is being developed by the company MINTEK from South Africa.
As one of three technological options for pre-processing manganese ore, the DLR Institute of Solar Research is researching high-temperature solar technology. The Helmholtz Zentrum Dresden-Rossendorf, the Norwegian research organisation SINTEF and the Norwegian University of Science and Technology (NTNU) are comparing the different technologies for preheating by means of a Life Cycle Assessment (LCA).
Multinational cooperation in the PreMa consortium: leading research organisations and manganese ore processing industries
The PreMa consortium consists of all the manganese alloy producers in Western Europe and one from South Africa, innovative technology providers for manganese processing and the use of renewable energy sources, and research and academic institutions with global expertise in manganese ore processing and the use of solar thermal energy. The expertise of the different partners brought together in the consortium makes it possible to cover the entire value chain and various specific needs for development in PreMa. The multinational collaboration strengthens the cooperation between Africa and the EU in the field of raw materials.
This project has received funding from the European Union's Horizon 2020 research and innovation programme (grant agreement number: 820561).