 When smelted for steel, 1000 pounds of sand yielded about 100 pounds of steel, 100 pounds of slag, and 90 pounds of pig iron.Slag and pig iron that were not suitable for use were then melted together to form wrought iron, of which 1000 pounds mixed produced about 500 pounds of iron.Unlike the rest of Eurasia and Africa, there is very little archeological evidence to suggest that bloomery smelting was used in ancient China.