Manganese Alloy Production
Manganese alloys began 2005 in a position of relative oversupply and returned to equilibrium in the second half of the year due to production cutbacks made by alloy producers as well as rebounding demand. Total world production of manganese alloys reached 10.7 million metric tons, down by 1% from 2004. As in past years, manganese alloy production was dominated by China, producing approximately 43% (4.6 million mt). All other regions of the world showed marked decreases in production, while Chinese production grew by 8%.
Chinese measures to control production and consolidate the industry continued with the elimination of its export tax rebate (8%) scheme for manganese alloys. The government also cancelled the 13% tax rebate on manganese metal, and eliminated the manganese alloy tolling business. In addition, Chinese steel producers’ manganese alloy inventories began the year much higher than normal. Therefore, despite the strong growth in steel demand, manganese ore imports, 4.5 million mt in 2005, did not experience the same explosive growth as in 2004 (a 67% increase).
Global production of silico-manganese (SiMn) reached 6.0 million mt, which was greater than the combined production of high carbon ferro-manganese (HC FeMn) and refined ferromanganese (Ref FeMn), their respective totals being 3.5 million mt and 1.2 million mt. SiMn is commonly used in the production of steel long products, critical components in the construction industry. A vivid example of this is China, where domestic SiMn production reached 2.75 million mt (up 9% from 2004) due largely to rapid investment in infrastructure that continues to fuel greater use of long products.
In 2005, the global unit consumption of manganese ferroalloys was approximately 10 kg alloy per mt of steel produced. This figure varies significantly from region to region with the differences related to the steel production process, the quality of raw materials used, (such as iron ore grades) and types of steel products produced.
Manganese Ore
Alloy production cutbacks directly impacted the demand for manganese ore with the consequence that production fell by 2% in the second half of the year.
However, over the whole year global manganese ore production increased by 11% to 34.7 million mt in 2005 (11.8 million mt in manganese content). China was the largest producer at 12.0 million mt (2.4 million mt of manganese content), followed by South Africa with 4.6 million mt (2.05 million mt in manganese content), Australia and Brazil producing 3.9 million mt and 3.5 million mt, respectively (1.8 and 1.5 million mt in manganese content).
Demand
World demand for manganese depends directly on the needs of the steel industry. There are numerous grades of steel and each requires a different amount of manganese. Unit consumption is determined by calculating the average requirement of manganese per ton of steel. Some manganese which is to be converted into steel is present in the iron (hot metal) coming either from the iron ore charge or from the addition of manganese ore to the blast furnace. This manganese is only a small part of the total requirement and it is partly oxidized during the different processes that convert the hot metal into steel. Hence most of the manganese addition is made in the steel melting shop. The majority of it is in the form of manganese ferro-alloys, but there are some cases when it can be added in the form of ore.
Part of the manganese is lost in the steelmaking process through oxidation. In the 1960’s and 70’s, when the oxygen-blown process progressively replaced the open hearth, Bessemer and Thomas processes, the subsequent improved manganese yield caused a decline in unit consumption. In the 1980’s further improvements in steelmaking (brought about by the development of combined blowing processes) meant even better manganese yields. Today, the average unit consumption for industrialized countries is a little over 7.5 kg of manganese per ton of steel. Changes in steel grade chemistry have had an effect on manganese requirements. For a constant unit consumption, manganese demand follows the growth in steel production. Manganese requirements for other metallurgical applications or for non-metallurgical uses do not represent a quantity large enough to significantly affect the evolution of the overall manganese demand as a direct function of steel production growth.
World Market
International manganese trade has long been closely linked with the demand of industrialized countries in Europe, North America, Japan and South East Asia. In the early 1980’s, a slowdown in steel production combined with a decrease in manganese unit consumption resulted in a decrease in the demand for manganese. This was partly compensated by new demands from China and CIS, all wanting to upgrade their own resources. These trends, added to the decrease in demand for ferruginous ore, increased the share of high grade ore in world trade.
Out of a manganese ore production of over 20 million tons per year, 8 million tons come onto the international market. A few producing countries, Australia, Brazil, Gabon and South Africa, account for over 85% of the world’s supply. From the mid-1970’s, South Africa, Brazil and Mexico started upgrading their exports by locally processing part of the ore into manganese-containing ferro-alloys.
Today, most of the manganese requirements of industrialized countries are supplied in the form of alloys. As a result, the UK and Germany have has almost completely abandoned local production of manganese alloys and the USA is now only a minor producer. In Europe, countries such as France, Norway and Spain have continued to be large exporters of these ferro-alloys.
Manganese and Manganese Alloy Production
With the exception of Japan, where steelmakers developed about ten years ago the direct use of manganese ores, most of the manganese ore used by the steel industry is processed into suitable metallic alloy forms.
Manganese metallurgy is very similar to iron metallurgy except that a higher temperature (over 1200°C) is required for the reduction of manganese oxide. Standard (or high carbon) ferromanganese, which is to manganese what pig iron is to iron, is a very commonly used alloy. It contains more than 76% of manganese and about 7% carbon, and can be produced either in the blast furnace or in the electric furnace. Production world-wide was about 3.4 million tons in 2000.
Another high tonnage alloy is silicomanganese, which was first produced at the beginning of the 20th century, when calcium carbide furnaces were reconverted to produce ferroalloys. The standard grade contains 14-16% Si, 65-68% Mn, with about 2% carbon. Lower carbon levels result when the silicon content is increased. Special grades with up to 30% Si are produced for use in the manufacture of stainless steel. World production of SiMn was about 3.5 million tons in 2000.
The steel industry also requires manganese alloys with less carbon than that contained in standard ferromanganese. For a long time these alloys, medium-carbon and low-carbon ferromanganese were both produced by a silicothermic process involving the reaction of silicomanganese and manganese ore, the latter generally being reduced to near-MnO state by heating. At present, however, medium carbon grades (1% to 1.5% carbon) are produced either in the ladle or in the converter. For a lower carbon grade, silicomanganese must still be used in many cases. About 820.000 tons of medium and low carbon grades were produced in 2000.
Manganese metal was first produced by an aluminothermic process in 1898. Some commercial production took place in the early 20th century. The development of electrolytic manganese began on a pilot scale in 1940 and the first commercial-sized plant was built fourteen years later in the USA. The manganese is produced through the electrolysis of a sulphate solution and sold as “flakes” (which are the stripped cathode deposits) or as powder. In 1966, electrothermic manganese, with a purity between 93 to 98% Mn, was first produced on a commercial scale in France. The process uses high-silicon silicomanganese to yield extremely low carbon levels. Approximately 150.000 tons of electrolytic manganese metal were produced in 2000.
Levels result when the silicon content is increased. Special grades with up to 30% Si are produced for use in the manufacture of stainless steel. World production of SiMn was about 3.5 million tons in 2000.
The steel industry also requires manganese alloys with less carbon than that contained in standard ferromanganese. For a long time these alloys, medium-carbon and low-carbon ferromanganese were both produced by a silicothermic process involving the reaction of silicomanganese and manganese ore, the latter generally being reduced to near-MnO state by heating. At present, however, medium carbon grades (1% to 1.5% carbon) are produced either in the ladle or in the converter. For a lower carbon grade, silicomanganese must still be used in many cases. About 820.000 tons of medium and low carbon grades were produced in 2000.
Manganese metal was first produced by an aluminothermic process in 1898. Some commercial production took place in the early 20th century. The development of electrolytic manganese began on a pilot scale in 1940 and the first commercial-sized plant was built fourteen years later in the USA. The manganese is produced through the electrolysis of a sulphate solution and sold as “flakes” (which are the stripped cathode deposits) or as powder. In 1966, electrothermic manganese, with a purity between 93 to 98% Mn, was first produced on a commercial scale in France. The process uses high-silicon silicomanganese to yield extremely low carbon levels. Approximately 150.000 tons of electrolytic manganese metal were produced in 2000.
