Definitions by sentinel75

Pig-iron 

Solid iron taken from a blast furnace; first metallic product after the reduction of iron ore. Full of impurities and brittle. Almost always further refined to steel or cast iron. In molten form, referred to as hot metal

The largest blast furnaces in the world can produce 10,000 tonnes per day of pig iron.

Pig-iron by sentinel75 May 10, 2005

hot metal

Any molten metal other than mercury, e.g. iron and steel, lead, tin, aluminium, copper, silver, gold, platinum, etc. Usually used in industry to refer to the product of melting furnaces.

Furnaces 4 and 5 can each melt and tap about 6 tonnes of hot metal.

hot metal by sentinel75 May 10, 2005

pig 

1. Crap metal, only good for scrap. Remelting and cleaning may make it good again
2. To get rid of such hot metal from a furnace

The (metal) melt was pigged because the silicon was too high

pig by sentinel75 May 10, 2005