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Energy efficient, primary production of manganese ferroalloys through the application of novel energy systems in the drying and pre-heating of furnace feed materials.

Periodic Reporting for period 1 - PreMa (Energy efficient, primary production of manganese ferroalloys through the application of novel energy systems in the drying and pre-heating of furnace feed materials.)

Reporting period: 2018-10-01 to 2020-03-31

The overall objective of PREMA is to demonstrate a technology for pretreatment of Manganese ores that will enable to increase energy flexibility, energy efficiency, enhance raw material use of fines, and reduce CO2 emissions in production of Mn-alloys.
Various pretreatment technologies using different energy sources like: CO-rich industrial off-gas, bio-carbon and solar thermal will thus be developed and demonstrated.
Design, engineering, cost figures and impact for industrial full-scale will be made together with a business plan for industrial implementation during the project (see implementation part).
From the start of the project and during the first reporting period a main focus have been to identify the most actual ores for pretreatment and the most actual technologies to concentrate the research and development towards.
This work has been done as a cooperation between all the partners in common meetings.

Different pretreatment technologies were evaluated at a Technology selection workshop in WP1.
Pretreatment in Rotary kiln and pretreatment in Shaft furnace were identified as the technologies with highest potential to be industrialised with the planned reduction in CO2 emission and energy reduction.
Further investigations and developments will focus on theese. To achieve the goals for CO2 and energy reduction, the raw materials must be transported warm to from the pretreatment unit to the Mn-alloy furnace.
An integration of technologies to ensure this will be a part of the development.

A pilot rotary kiln at Eramet Ideas have been updated and two campaigns have been run where the materials were successfully heated to 600°C.
The results look promising and will continue with further evaluations and pilot tests. A pilot submerged arc furnace (SAF) for Mn-alloy production at SINTEF/NTNU has been modified for investigations of pretreated ore.
Four pilot tests with untreated ore have been run as reference tests. The effect of pretreatment will be investigated when materials from the pretreatment pilots are ready.

Preheating and pretreatment with different gas mixtures have been investigated in laboratory scale up to 2kg and in rotary kiln pilot experiments described above.
It has been shown that it is possible to dry and preheat ores to 600 °C with air and with various CO/CO2 gas mixtures.
It has been demonstrated through laboratory experiments that Mn-ores can be dried, preheated to 600 °C and partly reduced in air and CO/CO2 gas mixtures.
Obtained degree of prereduction vary with ore type, is limited with air, and increases with % CO in the gas mixture.

Solar resource evaluation in different countries have shown that both Spain and South of France are suitable for thermal solar installation. Western part of South Africa will be ideal for thermal solar installations.

HSC and HSC Sim has been chosen in PreMa as tools for simulating the process for integrated Mn-ore pretreatment and Mn-alloy production.
Models that enables comparison of CO2 emission and energy consumption in different scenarios have been developed.

The HSC models will be combined with the LCA tool GaBi to give more information about the sustainability of the different scenarios.
The models have been used for simple cases but are still under development based on new input from other works.
The main objectives in this project:
Produce Mn-alloys in a new two stage process with pretreatment in a separate unit developed in PREMA followed by final reduction to Mn-alloys in sub-merged arc furnace (SAF) by current technology.
Provide a technology for pretreatment of manganese ores based on sustainable energy sources and with flexibility in choice of energy source
Be able to use solar thermal energy as energy source in production of Mn-alloys
Provide technology suited to pre-treat all actual Mn-sources
Assess the sustainability and robustness of the developed technology
Prepare for industrial implementation the developed technology for separate pretreatment of Mn-ores by sustainable energy sources
Exploit the results of the research, organisation of trainings and workshops

The main impacts can reach:
- 15% reduction of operating cost
- 20% increase in energy efficiency
- the total CO2 emissions decrease would be around 20%