Before we understand lead refining or casting, let us define lead. The chemical element, lead is a soft, bluish-white or grayish metal and makes up 0.0013% of the Earth’s crust. It is very malleable, ductile, and dense and is a poor conductor of electricity. It is highly durable and resistant to corrosion. It’s properties of ductility, ease of welding, low melting point, high density, and ability to absorb gamma radiation and X-radiation allow for its many uses in the world today.
Lead is a very common element and easy to extract. It is typically found in very small amounts in ores such galena, anglesite and cerussite. Once the ore is removed from the veins or lodes in the Earth, the ore is treated at concentrating mills. Here the ore is finely crushed to particle diameters sometimes to less than 0.1 mm. The powdered lead will then go through a floatation process to remove waste rock, known as gangue. The lead concentrates (containing 40 to 80 percent or more lead) are then shipped from the concentration mill to the smelter to be refined.
The Parkes zinc-desilvering process is the most widely used pyrometallurgical method of refining lead. Metal from the smelting furnace is melted in an indirect-fired kettle or pot and the trace elements are combined to produce the desired alloy. Lead is first melted and again allowed to cool below the freezing point of copper, which crystallizes, and along with any remaining nickel, cobalt, and zinc is removed by skimming.
The molten, refined, or alloyed lead is then cast. Lead casting is the manufacturing process in which liquid metal is poured into a mold – by a crucible — that contains a negative impression of the intended shape. Lead is pumped by heated pipes from kettles to a casting reservoir, or casting wheel, which directs a measured amount of lead into steel or cast-iron molds.
Medi-Ray is devoted to innovation in lead metal technology. We offer die-casting and automated gravity pour casting (hand casting). Custom casting equipment allows the manufacture of low porosity, high density metal castings.
Since 1970 Medi-Ray has been designing and manufacturing lead casting products. If you’re interested in knowing more about products of custom lead casting or would like to make a purchase, then we will be pleased to help. We also offer a “just-in-time” delivery schedule for your convenience. (877) 898-3003