Supplementary Cementitious Materials, silica and iron oxide will be produced as valuable by-products of magnesium extraction from almost 100% fly ash waste in a new demonstration facility being constructed east of Melbourne.
Latrobe Magnesium (LMG) is constructing a 1000 tpa demonstration magnesium production plant in the Latrobe Alley in Hazelwood North (pictured), which is expected to begin production mid-2023. The company is repurposing buildings to house plant and machinery and will build external facilities including a fly ash receival area, fly ash storage tanks, storage silos and container storage facility.
The company has developed what it calls a ‘world-first’ patented hydromet extraction technology that uses fly ash from brown coal power plants. The process dissolves magnesium, iron and calcium minerals with hydrochloric acid and leaches out magnesium as MgCl2,. Iron as Fe2O3 is removed and calcium as calcium carbonate. The MgCl2 is converted into magnesium oxide and recovers the hydrogen chloride for reuse in the process. This processes MgO into Mg and supplementary cementitious material (SCM) using the thermal reduction process.
The process produces 60% lower CO2 emissions than the industry average, according to LMG. Once a successful demonstration is complete, LMG says it will construct a 10,000 top commercial production facility.
The company believes this will enable it to operate at globally competitive costs, with low CO2 emissions. Global demand for magnesium is reaching one million tpa and is projected to double over the next few years, according to LMG. Fifty jobs will be created in the first year of operation and the expansion plans are expected to create another 300.