Application - Submerged arc furnace (ferroalloy)


Ferronickel is mainly produced in submerged-arc furnaces by reducing lateritic nickel ores. The process aims to transfer most of the nickel into the metal phase. It starts with pre-heated and pre-reduced ores which are hot charged as calcine (at temperatures of up to 800 °C) into the furnace. Then the final nickel reduction takes place in the submerged-arc furnace. Usually, round furnaces are used for smaller and medium quantities, whereas large capacities are produced in rectangular furnaces. Nickel contents of up to 35 % in the FeNi are possible.

Today, advanced high-power FeNi-smelting furnaces are very efficient and implement a series of improvements such as various sidewall cooling methods as well as AC thyristor controls. These ensure better operation, higher and more efficient power input, and less overall maintenance.

The world's largest submerged-arc furnace for FeNi was recently supplied to POSCO SNNC, a joint venture between the Korean company POSCO and the mining company SMSP, which is based in New Caledonia. The power rating of the rectangular FeNi smelter is 135 MVA, resulting in a total nominal effective power input of 100 MW. The large-capacity furnace comes with impressive dimensions of 40x15x8.5 m, making it the world's largest electric smelter. SMS group was proud to work with such a high-reputation partner on this project. Finallly, in January 2015, the first metal was tapped, and 100% capacity load was already demonstrated in 2015. This project exemplifies our superior position in FeNi smelters.

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What distinguishes high-carbon ferrochrome is the carbon content of 4-8%. It's usually used in AOD converters to produce alloyed steel grades. Due to environmental restrictions, ferrochrome is commonly produced in closed, stationary furnaces. Medium-carbon chrome alloys and low-carbon FeCr are produced in combined process stages. Both products require special slag metallurgy to attain high chrome yields.

We also landed a major order from Kazchrome JSC for the engineering and supply of an HC FeCr plant. The complex was installed and commissioned at the existing FeCr plant in Aktobe/Kazakhstan. Here, we supplied four DC-based smelters with a power input of 72 MW for each furnace. Now the annual production of the plant (melt shop No. 4) is approx. 440,000 t of HC FeCr. It was a big day when the first metal was tapped in November 2014. That's because it was the first time we demonstrated on an industrial scale that the furnaces can directly process the chrome ore fines. To improve operation, the system includes DC electrode columns, and the results so far are favourable.

Along with Metix, SMS group is a leading supplier of new FeCr furnaces and has also modified numerous existing furnaces worldwide. Most of our recent installations have been in South Africa, which has the largest known chrome ore deposits. Listed among our customers in the region are IFM, Glencore, and Hernic.

SMS group also upgraded two 66 MVA FeCr furnaces for IFM/South Africa. Furthermore, we installed the core equipment in a new Xstrata plant named Lion 2. Our supply scope included two 75 MVA FeCr furnaces. They were combined with Xstrata's PREMUS technology for pre-reduction of the Cr ore. The plant was commissioned in 2013. Previously, we upgraded Lion 1, for instance, replacing the electrode columns for the two 63 MVA FeCr furnaces.

Another project, for Eti Krom in Elaziğ, Turkey, comprised the modernization of two FeCr furnaces. New here is that the revamped furnaces are connected to a 3 x 10 MVA transformer and produce approx. 90,000 tons of HC FeCr per year. Since commissioning in 2011, the smelters have operated without a hitch. It was also an endorsement of our success that Eti Krom A. Ş. contracted SMS group to install an energy recovery system and a gas cleaning plant connected to the two recently installed furnaces. Right now, the equipment is being commissioned. We calculate that 5 MWh/h will be recovered as electrical power.

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FaCr image
SMSgroup Image
SMSgroup Image

FeMn / SiMn

Ferro-manganese is usually available on the market in the form of high-carbon (6-8%C), medium-carbon (1 - 4%C), or low-carbon (< 0.4%C) products. There are also alloys with high Si contents (15 - 20%) known as silicomanganese. High-carbon ferro-manganese and silico-manganese are produced in open or closed furnaces.

Yunnan Metallurgical Group Co Ltd contracted SMS group to carry out the basic engineering for China's largest closed 67.5 MVA SiMn furnace. We also supplied the core equipment (1,750 mm electrode system, copper roof, and lining). Commissioning took place in 2011.

Here, SMS group attracted the full engineering, procurement, and construction (EPC) contract from Sakura Ferroalloys for a project in Eastern Malaysia. You may know that this company is a tripartite joint venture between Assmang Ltd (itself a joint venture between African Rainbow Minerals Limited and Assore Limited) of South Africa, Sumitomo of Japan, and Taiwan's China Steel Corporation. This is a major project consisting of two 81 MVA FeMn/SiMn closed submerged-arc furnaces, gas cleaning, raw material handling, product handling, and associated services, plus infrastructure.

FeMn / SiMn image
FeMn / SiMn image
SMSgroup Image

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