Work

Thermal treatment of lizardite for mineral carbonation using high flux radiation

Year: 2024

Type: article

Abstract: Heat-treatment of lizardite with a high-flux radiant source to temperatures of up to 630 °C, at rates greater than 10 °C/s and exposure times up to 10 minutes, was carried out for the first time in this study. The novel proposed radiant heat activation process was shown to enhance the subsequent carbonation potential when used as a precursor to dissolution experiments for magnesium extraction. It was found to increase magnesium carbonate yields by up to 58% following dissolution in a saturated carbonic acid solution at room temperature for 2 hours (i.e., exposed to carbon dioxide, CO2, at a partial pressure of 1 atm) compared to the same material heat treated in a rotary kiln. The magnesium extraction from the radiantly heat-treated samples was found to: 1) increase monotonically with increasing heat-treatment temperature (up to 630 °C), 2) increase with increasing holding time at the set heat-treatment temperature (up to 480 s), and 3) decrease with increasing heating rates (from 10 to 25 °C/s) for the same heat-treatment temperature. Mineral analyses showed that the heat-treated samples providing the greatest magnesium extraction had significant dehydroxylation of the crystalline lizardite, as the atomic structure is rearranged into meta-serpentine and amorphous phases. The results suggest that the phases formed during heating to moderate temperatures (530 < T < 630 °C) with relatively short exposure times (<10 minutes) are highly beneficial for magnesium extraction from the particles, potentially improving carbonation performance and the viability of mineral carbonation using lizardite as the feedstock for long-term chemically stable storage of carbon.

Source: Fuel

DOI: 10.1016/j.fuel.2024.134187