Traditional Pidgeon Process used in China
Historical Development of Silicothermic Mg Technology
Silicothermic magnesium technology was initially developed in the early 1940’s by Dr. Lloyd Pidgeon.
2CaO.MgO + Si = 2 Mg(g) + 2CaO.SiO2
Dominion Magnesium opened the world's first Pidgeon Process plant at Haley, Ontario Canada in 1941. The plant was subsequently operated by Timminco Ltd producing the world’s highest purity 99.98% Mg for specialized applications until its closure in 2008.
The Pidgeon Process suffers from its reliance on small diameter, high alloy retorts operating under high vacuum at 1200C. Since each retort has a Mg production capacity of only ~ 75 kg per day, commercial level production requires hundreds if not thousands of small-scale vacuum retorts clustered in fossil fuel fired furnaces which leads to a highly labour & maintenance intensive operation. By the early 1990's, silicothermic magnesium production had been largely eclipsed by electrolytic technology which produced over 85% of the world’s commercial grade magnesium metal.
The Chinese version of the Pidgeon Process was developed using coal based fossil fuels in the late 1990's. In doing so, Chinese producers brought magnesium technology back some 60 plus years to a highly polluting, energy and labour-intensive version of the Pidgeon process. Even though the Chinese Pidgeon Process operates at much lower productivity, & raw material utilization efficiency than the traditional Pidgeon Process commercialized in Canada, cheap labour, abundant low cost raw materials, lax pollution regulations & a low CAPEX, enabled Chinese magnesium producers to capture over 80% of world production within a few short years.
Tech Magnesium's Clean Process represents high efficiency, low cost silicothermic technology that has a carbon footprint that is about 3 times lower than the average Chinese Pidgeon Process plant.
CLEAN Mag Process Route Breakthroughs
Tech Magnesium’s CLEAN Process Route
A highly flexible and profitable patent pending process route utilizing silicon (Si) reduction of calcined dolomite (CaO.MgO), and a proprietary reactor derived from proven industrial equipment.
The CLEAN Process Route maximizes chemical, energy, and raw materials utilization efficiency to co-produce magnesium alongside a commercially valuable mineral. This results in the lowest magnesium production cost in the western world and a Carbon Footprint that is three times lower than Chinese magnesium.
The CLEAN Process Route employs Tech Magnesium's proprietary silicothermic reduction methodology, utilizing its atmospherically sealed electric furnace and isothermal condenser design to co-produce high-purity molten magnesium together with fused 2CaO.SiO2.Al2O3 ('white slag").
Importantly, the CLEAN Silicothermic Process Route employs the same Tech Magnesium Co-Production Technology equipment used for the ULTRA CLEAN Aluminothermic Process Route. Consequently, by altering the raw material mix, a single Tech Magnesium Co-Production plant can use either the ULTRA Clean and/or the CLEAN Process Route to co-produce high purity Mg metal along side five different commercially valuable minerals. Such process flexibility allows the facility to operate in the most profitable manner aligned with market demand.
Proof of the CLEAN Process concept: was established by rigorous thermodynamic modelling conducted by Professor Arthur Pelton, Polytechnique Montreal – an internationally recognized metallurgical thermodynamics expert & co-developer of industry leading FactSage thermodynamic modelling software. Pelton’s thermodynamic model was confirmed by bench scale experimental test work carried out at Process Research ORTECH, Mississauga, Ontario Canada.
ORTECH's Test Work Mass Balance confirms Pelton's Model
CLEAN Mag Process Step Wise Evolution
CLEAN Process Route Benefits
CLEAN Silicothermic Process Route Performance
Using Pelton’s fundamental modelling & Process Research ORTECH’s test work results, Tech Magnesium applied its extensive metallurgical industrial processing expertise to develop high efficiency, low cost, clean, patent pending silicothermic magnesium production technology.
Maximize Raw Material Utilization Efficiency to lower material costs & lower energy consumption: the process' high heat & mass transfer rates are designed to enable highly efficient reduction of CaO.MgO to high purity magnesium vapor with an industry leading Silicon Efficiency of 94.2% & a Magnesium Recovery of 92.3%.
Low Carbon Footprint: the carbon footprint of the CLEAN Process has been determined by Process Research ORTECH as 9.1 kg CO2 per kg Mg metal when using renewable electricity for both Mg & FeSi production and CaO.MgO produced from raw dolomite in a natural gas fired rotary kiln. As such, the Tech Magnesium CLEAN Process carbon footprint is significantly lower than the average for Chinese Pidgeon plants. Further reduction in the process’ carbon footprint is expected by employing technology to recover magnesium condenser waste heat to produce steam or electricity.
Innovative Electrical Process Reactor Design Replaces Low Productivity, Fossil Fuel Fired Retort Production used in the Pidgeon Process: Tech Magnesium Co-Production Technology utilizes industrially proven electric furnace technology adapted specifically to enable the most efficient magnesium production. This proprietary Reactor provides the following benefits:
- replaces fossil fuels with clean renewable electricity, significantly reducing the process’ carbon footprint.
- provides an atmospherically tight design critical for efficient Mg metal recovery.
- facilitates exceptionally high mass & heat transfer rates which are the efficiency limiting constraints in all thermal Mg processes.
- facilitates atmospheric Mg production pressures reducing the need for a vacuum.
- facilitates condensation of Mg process gas to molten Mg metal using Tech Magnesium’s proprietary isothermal condenser. Molten magnesium condensation is an important enabler to increase Mg yield, reduce energy consumption, lower production costs and facilitate efficient molten metal transfer methods.
Low, Competitive OPEX: Tech Mag CLEAN Process produces Mg at a cost lower than both Chinese & Electrolytic magnesium production and is on a par with the world average cost to produce aluminum, once adjusted for density differences between Mg & Al.
Low CAPEX per ton: a Tech Magnesium Co- Production Technology plant equipped with the CLEAN Process Route plant can be built in 5,000 MT modules in tune with market demand. Most importantly, its capital cost is less than US $3,500 per MT Mg which is ~ 4 to 6 times lower than the capital cost of a typical magnesium electrolytic plant thereby ensuring a very attractive ROI.
CLEAN Mag Process Competitive Edge
Status Update & Next Steps
The CLEAN Silicothermic process chemistry has been confirmed by Prof. Pelton's FactSage thermodynamic modelling which substantiates a magnesium Yield & Silicon Efficiency of over 90%. Pelton's modelling predictions have been confirmed by bench scale experimental testing at Process Research ORTECH.
Tech Magnesium's proprietary reactor has been designed to utilize industrially proven electrical heating technology that will maximize heat & mass transfer rates to achieve the high energy & raw material utilization efficiencies predicted by Pelton.
The CLEAN Process can be configured to use either a batch or a fully continuous reactor.
Tech Magnesium has completed a detailed work plan and planning budget for the next round of development work. It has also prepared a Case Study analysis to identify CAPEX & OPEX costs and the expected ROI for a 50,000 MT Mg Co-Production Technology facility.
Tech Magnesium is seeking strategic partner(s) to support the final pilot scale testing phase with the aim of producing molten Mg using Tech Magnesium's proprietary isothermal condenser.
