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Since the mid-1990s, to meet the demands of global sustainable development, the research, development, and application of magnesium and magnesium alloys have entered a period of rapid growth. During this period, thanks to its advantages in resources, energy, and costs, China’s magnesium industry grew rapidly and quickly took control of the global supply of primary magnesium. According to customs statistics, in 2003 China’s exports of magnesium products amounted to 298,000 tons, accounting for approximately 66.6% of the world’s total shipments. 98% of China’s primary magnesium production is carried out through silicothermic reduction, also known as the Pidgeon Process, and it is expected to become the main method for producing metallic magnesium in China in the future. Experts are concerned that without a guarantee of a high-quality and relatively stable supply of raw materials, the magnesium industry is likely to experience overall decline. Therefore, the horizontal Pidgeon process reduction units deployed in magnesium plants across China cannot fail to attract significant attention. Such production facilities have the advantages of a simple process route and easy control of process parameters; however, they also suffer from significant drawbacks such as poor mass and heat transfer during the reduction process and low thermal efficiency, which limits the production scale of magnesium plants using the Pi Jiang method. 1. Thermochimistry of magnesium production by the Pidgeon process. The thermoreduction reaction for magnesium production via the Pidgeon process takes place in a horizontal reactor, and the stoichiometric equation for the overall reaction is given by equation (1): 2MgO·2CaO + Si(Fe) → Ca2SiO4 + 2Mg + Fe (1) The free energy function ΔG of reaction (1) as a function of temperature T is given by equation (2): ΔG = 115600 + 11.74TlogT – 100.38T (2) The relationship between the reaction heat ΔH and temperature T is shown in equation (3): ΔH = 115600 – 5.098T (3) Equation (2) allows us to determine the critical temperature Tc for this reduction reaction. For reaction (1) to proceed in the forward direction, the reaction temperature must be above the critical value Tc; the higher the temperature, or the more significantly the reaction rate is increased, the more readily reaction (1) can proceed to completion. The actual reduction process takes place under vacuum; this **lowers the critical temperature Tc and provides a pathway for the transport of magnesium vapor, but it also reduces the heat transfer efficiency of the reactants, resulting in a complex and unique vacuum thermal reduction mechanism in the Pidgeon process. 2 Introduction to the testing setup: This test makes use of the production facility, with the testing activities carried out in parallel with production. The reduction reaction apparatus consists of a horizontal reduction tank, a heating furnace, and a vacuum system. Figure 1 is a schematic diagram of the reduction tank structure; the tank is filled with raw materials and heated from the outside. The calcined dolomite is thoroughly ground and mixed with a certain proportion of ferrosilicon and fluorite, then pressed into balls. These balls are placed in containers in fixed quantities, with the containers sealed ； Vacuum evacuation and heating of the reduction furnace are initiated simultaneously to achieve a vacuum level of 13.3 Pa within the tank; under conditions of varying reaction temperatures and reaction durations, the conversion efficiency of the reduction reaction is evaluated based on the yield per tank. Energy consumption is determined through the analysis of production statistical reports. 3 Results and Discussion 3.1 Comparison between coal-based reduction furnaces and gas-based reduction furnaces The energy structure of China’s magnesium industry relies primarily on coal. There are two types of furnaces used for magnesium reduction, with furnace gas and raw coal serving as the respective fuels. Figure 2 is a schematic diagram of the structure of a gas-reduction furnace; from an environmental perspective, professional design firms tend to recommend this type of furnace. However, in recent years, in an effort to reduce fuel costs and the investment required per ton of magnesium produced, manufacturers have been reluctant to use gas-fired furnaces; as a result, over 90% of newly built reduction furnaces are of the direct coal-firing type, which has exacerbated dust pollution. Both types of reduction furnaces have their advantages, but the gas furnace still holds a clear advantage, which lays the foundation for subsequent process and technical improvements. The disadvantage of gas reduction furnaces is the need to add a gas production unit; common gas generators use bituminous coal to produce gas, which increases the cost per ton of magnesium. This is the main problem that this article aims to address. 3.2 Improvement of the operating procedures for energy-saving reduction furnaces: The reduction process is the main energy-consuming part in the Pidgeon process for magnesium production. Based on heat balance calculations, two phenomena deserve attention. First is the fuel consumption required for heating the reduction furnace, which accounts for about 2/3 of the total fuel consumption in the magnesium production process ； Secondly, within the energy consumption of the reduction furnace, the energy used to heat the raw material pellets and to provide the heat necessary for the reaction accounts for only 3.66% and 19.83% of the total energy consumption of the reduction furnace, respectively ； Meanwhile, the ineffective heat loss was as high as 76.51%. The existing Pijiang process indirectly heats the pellet feed in the reduction tank, which results in a significant reduction in the effective utilization rate of heat; this is an inherent characteristic of the current process. We will discuss in a separate article the options for replacing the outdated equipment of the traditional Pijang method. This article aims to emphasize that there is still significant room for energy savings in the reduction process, and engineering and technical personnel can certainly take advantage of this situation to make a difference. Theoretical analysis and practice show that the best approach to eliminating pollution in magnesium smelting reduction furnaces involves two key elements: the first is energy conservation, that is, reducing emissions by lowering fuel consumption per ton of magnesium produced ； The second is to use pollution-free clean energy. Magnesium plants can choose to implement it based on their own conditions. A careful analysis of the performance characteristics of the two types of reduction furnaces shown in the table reveals that using a gas furnace as the main furnace type for the Pi Jiang process reduction step is a necessary condition for implementing a clean and energy-efficient solution; such furnaces will be phased out in the process of cleaning up these systems. To determine the optimal process parameters for the production of gas furnaces, this paper examined the output per furnace and per tank under reduction cycle times of 6, 7, 8, 9, and 10 hours respectively. The results show that, under production conditions where other process specifications are strictly followed, these reduction processes, which exhibit significant differences in reduction time, are not directly proportional to the yield. Since the preparation process for gas stoves takes little time, they heat up quickly with a short idle burning time ； The temperature inside the furnace is uniform, facilitating automatic control. These advantages enable the gas furnace to maintain stable operation over an 8-hour cycle. Achieving an 8-hour production cycle in gas-reduction furnaces is crucial for reducing flue gas emissions, which is mainly accomplished by lowering energy consumption and reducing unnecessary operating time. By reducing the usual 12-hour cycle to 8 hours, one additional shift can be carried out per day, resulting in a significant increase in production efficiency. 3.3 Clean fuel options Common clean fuels are producer gas and natural gas. The cost or price of both is high, and it is no longer acceptable for the magnesium smelting industry, which has low profit margins. The feature of this approach is that it combines the silicothermic method for magnesium production with the related coking and ferrosilicon smelting processes, using the off-gas from coking as fuel for magnesium production. Products are interrelated and intertwined, extending the industrial chain. Utilizing coke oven gas is a clean industrial solution that enables significant technological innovation in magnesium smelting at present. The model factories built in Ningxia and Shanxi have achieved good economic benefits as well as valuable experience in technological upgrades. Taking an annual production of 10,000 tons of primary magnesium as an example, merely by recovering gas, 70,000 tons of coal can be saved each year, resulting in cost savings of 20 million yuan in coal consumption expenses ； No smoke emissions, harmless to the environment. According to a report in the China Nonferrous Metals News on April 15, 2004, Shanxi and Shaanxi produce 150 million tons of coke annually, with 80% of the by-product coke oven gas being vented. Magnesium plants using the Pidgeon process in China are moving to areas where there is an abundance of coke oven gas. 4 Conclusion Reducing energy consumption and improving resource utilization are important measures to achieve clean magnesium production using the Pi Jiang method. This paper presents a set of industrially viable solutions, proven through practice, regarding the current status of the Pi-Jiang process. The features of these solutions are as follows: first, heat energy and waste gas emissions are reduced by saving energy and reducing production cycles, thereby shortening the reduction reaction time from 12 hours to 8 hours ； II. By using the modified gas as the main equipment in the reduction furnace and recovering waste coke oven gas as a clean fuel, an industrial chain that combines magnesium production, coking, and ferrosilicon manufacturing and features complementary functions has been established, thereby improving the technology and equipment standards for magnesium production using the Pi Jiang method.