STOP SMOKING! Techno-economic feasibility of solar phosphate rock calcination in Tunisia

Cooperating countries: Tunisia and Austria

Coordinating institution: Univ.-Prof. Ali Tlili, University of Sfax

Partner institutions: Dr. Nils Haneklaus, University for Continuing Education Krems

Project duration: 1 September 2021 - 31 August 2024

Calcination of minerals is responsible for approximately 10% of all human carbon emissions
worldwide. Carbon dioxide is produced through the calcination reaction itself (roughly 50%) and through burning fossil fuels (another 50%) to provide the heat required for mineral calcination (calcinare = to burn lime, latin). Dr. Nils Haneklaus developed a system that can calcinate minerals without burning fossil fuels using a heat transfer fluid that could be heated using concentrated solar power plants, allowing for less carbon emissions (50% less) and increased resource efficiency in mineral and metallurgical processes. In the 2-year project “STOP SMOKING!” Prof. Ali Tlili from Sfax University (US) and Dr. Nils Haneklaus from University for Continuing Education Krems will investigate the technoeconomic feasibility of potentially using this system for solar phosphate rock calcination in Tunisia.

The core aim and outcomes of the project “STOP SMOKING!” is to reduce carbon emissions during phosphate rock calcination in Tunisia (and if applicable elsewhere). These efforts contribute directly to SDG 13 (Climate Action). Mineral calcination worldwide contributes to roughly 10% of anthropogenic CO2 emissions. The largest share of this (>90%) comes from cement production. Roughly 2% of CO2 emissions during mineral calcination can be attributed to phosphate rock calcination (0.2% of global anthropogenic CO2 emissions).

Should we be able to develop a system for mineral calcination of phosphate rocks, significant CO2 emissions could be mitigated in Northern Africa (Algeria and Morocco) where phosphate rock is presently calcined. Tunisia could profit from inexpensive calcination in a way that huge amounts of groundwater could be left untouched as described in Chapter 2. An adapted version may in a next step be used for all kinds of mineral calcination (in regions with high solar radiation) that has the potential of reducing global CO2 emissions significantly. As a result of the largest economic growth taking place in the global south and Africa, 2-8% of all minerals calcined could be calcined in areas with high solar radiation without significantly higher transportation costs.