There are several mini
mills in Australia and quite a few in the USA and they produce a
considerable amount of steel from what is essentially quite a small plant. So
what is a mini mill?
Scrap steel is delivered by truck and tipped into the mill's scrap pit which has a capacity of 18,000 tonnes - carefully divided into four grades held in separate bays. That's enough to feed the mill for two weeks. STEP TWO
According to the demands of the furnace production schedule, the various grades are loaded into scrap buckets for transfer by rail trolley into the melt shop.
A mini mill is a steel production facility that uses an
electric arc furnace to melt the scrap steel. In contrast, the traditional
Integrated Steel mill has blast furnaces or basic oxygen furnaces using iron ore
and coke as the basic ingredients with some scrap thrown in. Although some
integrated mills have electric arc furnaces for specific purposes, the arc
furnace is the key component of a mini mill.
Over the past 20 to 30 years, there has been substantial growth
in mini mills. In 1970, mini mills accounted for less than 10% of US steel
production. These early mills typically produced between 100,000 and 300,000
tonnes per annum, with the number of grades of steel and product types kept to a
minimum. In 2001, mini mills produced nearly half of the steel shipped by United
States mills. Nor is it stopping there. Mini mills are no longer mini, with
production capacities now approaching 1,000,000 - 2,500,000 tonnes per annum
while still using a single but now quite large arc furnace. In addition, the
list of grades of steel produced and product types has increased