The Magnesite Pidgeon Process is one of the methods of magnesium metal production, via a silicothermic reduction. The Pidgeon method is less complex technologically, and because of distillation/vapor deposition conditions, a high purity product is easily achievable.

Introduction of Magnesite Pidgeon Process

The Pidgeon process is a batch process in which finely powdered calcined dolomite and ferrosilicon are mixed, briquetted, and charged in retorts made of nickel-chrome-steel alloy. The hot reaction zone portion of the retort is either gas fired, coal fired, or electrically heated in a furnace, while the condensing section equipped with removable baffles extends from the furnace and is water-cooled. Due to distillation, very high purity magnesium crowns are produced, which are then remelted and cast into ingots. Practical production requires roughly 35–40 MWh/ton of metal produced, which is on par with the molten salt electrolytic methods of production, though above the 7 MWh/ton theoretical minimum.

Advantages of Magnesite Pidgeon Process

1. Energy Saving

The refractory lining of the rotary kiln consists of the outer insulation made of light refractory brick and inner compound refractory bricks, which will reduce the heat emission on the shell surface of the rotary kiln. The pre-heater at the end of the rotary kiln will recycle the heat to preheat the material and save fuel by 40% and increase the output by 30%.

2. Low Consumption

The vertical cooler at the discharge end of rotary kiln recycles the heat of the calcined dolomite which is discharged from the magnesium rotary kiln, and will preheat the secondary air up to 600℃. The vertical cooler is integrated with kiln hood to prevent the waste caused by heat emission from the discharged calcined dolomite.

3. Environmental Protection

Two phases of dust collection including cyclone filter and bag filter, will control the dust emission below the limitation of the national standard.

4. High Degree of Automation

PLC control system improve the working efficiency.

Henan Zhengzhou Mining Machinery Co., Ltd began to manufacture equipment for Mg smelting industry from 1988, and focused on the technology upgrading and utilization. During 2003-2005, the company invented Vertical pre-heaterfor the calcination of dolomite. This kind of new pre-heater saves fuel by 40% and increases the output by 30%. The exhaust gas is recycled and dust emission can be controlled under 50mg/m3. This kind of new pre-heater takes up more than 85% in the market share. We also adopt the advanced and reliable technology of Pidgeon process for the magnesium production.