Recent FerroAlloys production and marketsMetalist
2.4 Recent FerroAlloys production and markets
As the ferroalloys are primarily used in steelmaking, different grades of alloys have been developed to fulfill the varying requirements of the steel industry. As discussed earlier, most of the chromium is added in the form of high-carbon charge FeCr (50% to 55% Cr, 2% to 5% Si, 6% to 8% C, and the balance is Fe).
Also, for different alloying purposes, different Cr-alloys are produced with higher Cr and lower carbon contents than in Charge HC (high-carbon) FeCr. Typical composition is 60% to 70% Cr, 2% to 3% Si, and in different carbon categories: high-carbon (HC) grades with 5% to 8% C, medium-carbon (MC) grades with 1% to 4% C, and low-carbon (LC) grades with 0.1% to 0.5% C.
Even lower carbon contents are available. The world leader in ferrochrome prouction is South Africa with 3.6 MT in 2008; China is second with 2.2 MT, followed by India and Kazakhstan with about 1 MT/year. Kazakhstan, South Africa, and India have the largest chromite resources known. Russia and Finland are the next big producers with productions of about 0.25 MT/year.
Over 80% of all FeCr goes into stainless steel and high-alloyed steels. The rest is used in low-alloyed steels (typically 0.3% to 2.0% Cr) to improve hardenability and strength. Concerning the need of FeCr for stainless steels, it is noteworthy that a significant share of the all Cr units (on average 30% to 40%) comes from recycled stainless scrap and the rest (60% to 70%) comes from “virgin” ferrochrome alloy.
Ferroalloys production is firmly coupled with steel production, and the time-dependent production rates follow each other.
A comparison of the production of the mentioned “bulk” ferroalloys since the 1980s reveals some interesting features. Concerning manganese alloys, there has been a clear transition from FeMn to SiMn. In the beginning of the 1980s FeMn was produced much more than SiMn, in the beginning of 2000 the produced amounts were equal, but in 2010 the FeMn/SiMn ratio was ~0.6 (Brown, 1984; Corathers et al., 2012; Fenton, 1996).
There have been some changes in production technology: ferromanganese production in blast furnaces has reduced from 30% to about 10%, and most FeMn production now occurs via submerged arc furnaces (SAF). All silicomanganese is produced in SAFs. Silicomanganese is a suitable addition to be used for the de-oxidation of most steels, whereas ferromanganese and ferrosilicon are used mainly for alloying purposes.
By calculating the apparent ferroalloy consumption per all kinds of steels produced, eventual trends in “alloying degree” can be observed. The average consumption of ferroalloys has been 2.2% to 2.4% of the mass of steel, but it has grown to 3% in recent years. However, this does not refer to real growth of “degree of alloying” but describes the fast growth of high-alloyed stainless steels. As most chromium is added as charge FeCr with low Cr content (50% to 55%), the quantity of the ferroalloy addition is still emphasized.
Despite the volatility of metals markets, ferroalloys production is rather steady as it represents one of the major backbones of steelmaking. Besides steels, ferroalloys are used also for special materials production (foundry castings, super-alloys, low-iron and nonferrous alloys, welding materials, etc.). Countries with reported ferroalloys production are marked (data collected from various sources as of 2010). Nevertheless, there is also local ferroalloys production in-house in some metallurgical plants for that company’s own use as well as occasional smelting campaigns to satisfy peak demands or to utilize locally available resources.