Magnesium ingot smelting process

The smelting methods of raw magnesium are mainly divided into two types: one is the silicon thermal reduction method; the other is the electrolysis method. At present, most domestic raw magnesium manufacturers use the Pidgeon method among the silicon thermal reduction methods. The following is a brief introduction to the more mature Pidgeon method.

The production of magnesium ingots by the Pidgeon method uses calcined dolomite or magnesite ore as raw materials, ferrosilicon as reducing agent, and fluorite as catalyst, and is metered and batched. After grinding and pressing into balls, they are called pellets. Put the pellets into the reduction tank, heat it to 1200°C, and evacuate the interior to 13.3Pa or higher to generate magnesium vapor. Magnesium vapor forms crystallized magnesium, also known as crude magnesium, in the condenser at the front of the reduction tank. After adding flux and refining, commercial magnesium ingots are produced, namely refined magnesium.

Pidgeon process magnesium smelting production process:

(1) Dolomite calcination: Heat dolomite to 1100-1200°C in a rotary kiln or vertical kiln, and burn it into calcined white (MgOCaO).

(2) Ingredients for ball making: Calcined white powder, ferrosilicon powder and fluorite powder are measured and batched, ground, and then pressed into balls.

(3) Reduction: Heat the ball in the reduction tank to (1200+10) ℃, and keep it under vacuum conditions of 13.3Pa or higher for 8 to 10 hours. The magnesium oxide is reduced to magnesium vapor, and becomes crude magnesium after condensation.

(4) Refined ingot casting: The crude magnesium is heated and melted, and then refined with a flux at a high temperature of about 710°C to cast it into magnesium ingots, also known as refined magnesium.

(5) Pickling: Clean the surface of the magnesium ingot with sulfuric acid or nitric acid to remove surface inclusions and make the surface beautiful.