Key Metallurgical Parameters of Fe-Ni Production During 1984–1997 and 2007–2017 at the Ferronickel Smelter in Drenas

The new Foundry of the new Ferronikel in Drenas is located near the source “Old Çikatove” 37 km northwest of Prishtina. The production of metallurgy until now in the Republic of Kosovo is oriented in processing ore of local mines, such as Golesh and Çikatove, and imported ore (from the year 2007) from Indonesia, Philippines, Guatemala, Albania, Macedonia and Turkey.

The processing is done using the electro-reduction process to prepare Fe-Ni as the final product. The fundamental establishments and the equipment of the foundry are two rotary kilns of the firm “Schmid” Copenhagen, two rotary kilns of the firm “Elkem”-Spikerverket, Oslo and two convertors LD of the firm Krupp, Dusseldorf [1].

In the new foundry in the new Ferronickel in Drenas, the process of Fe-Ni production passes through the following stages: processing of Fe-Ni ore and fuels and their delivery to appropriate bunkers where with the aid of conveyor belts they enter the rotary kiln. At a temperature of over 500°C using special equipment, the fuel enters, consisting of heavy-oil and pet - kok, that influence the temperature increase of the rotary kiln (over 700°C) and the qualitative production of calcine [2]. The calcine produced by the rotary kilns is sent to the electric furnace through special pipes where the Fe-Ni metal production process and the quantity of slag are realised.

The produced metal from the electric furnace is sent to the converter for refining, in which an amount of limestone is introduced, and oxygen is blown into it. After the refining, metal is poured into special equipment where we have the production of Fe-Ni metal, in the form of granules of the size of 15–20 mm and weight 5–15 g while the remaining slag in the converter is divided into the metallic part and the non-metallic part, where the metallic part gets back in the process [3].

In the new foundry of the new Ferronickel in Drenas during the realisation in 2007–2017, these Fe-Ni ores were used: ores from Kosovo (mines: Gllavice and Qikatove), ores from Albania, ores from Guatemala, ores from Indonesia, ores from the Philippines, ores from Turkey and ores from Macedonia. The composition of the ores is oxide and silicate. The annual average of Ni content in the Guatemala, Philippines, Indonesia ore is higher (Ni = 2%) compared with the Kosovar ore (Ni = 1.5%) and Albanian ore (0.99%) [3].

The industrial data are parameters based on the production process of ferronickel in Drenas, during the years 1987–1997, and the industrial production period of Fe-Ni during the years 2007–2017, directly from the production process of the Fe-Ni alloy [1, 3].

During the industrial processes of the analyzed years, we have determined:

The average of Fe-Ni ore in rotary kilns,

Figure 1

Figure 2

The research during the years 1984–1997 is based on the data from the archive of the ferronickel Plant, whereas the research during the years 2007–2017 is based on the laboratory and industrial work of the Fe-Ni alloy production in the Plant.

Figure 1 represents the production data of the iron-nickel, starting from:

Average of Fe-Ni ore,

The obtained amount of calcine during the years 2007–2017 is 40% higher than the calcine amount obtained during the years 1984–1997, a difference which comes as a result of a few factors.

During the years 1984–1997, the Plant's start is accompanied with great difficulties, among them the inability of reaching the high temperatures of 900–1000°C as provided by the Gipronickel project (the Plant project of 1983), which was a big problem because the temperature plays a crucial role in the process of rotary kilns and the development of pyrometallurgical processes in general [1].

The amount of calcine produced during the years 1984–1997, followed by very high impurity, was frequently interfered within the manufacturing process for the possibility of achieving production parameters as provided by the project (according to the archive and engineering of that time). These were the factors that influenced the low production of both Fe-Ni and Ni quantities in tons, compared with higher production quantities during 2007–2017. During the years 2007–2017, some changes were made to the ferronickel plant in Drenas which resulted in the higher production of Fe-Ni alloy:

Placement of Fe-Ni ore dryer during the years 2010–2012 [4].

Figure 3

From the analysis of research done during the years 1984–1997 and 2007–2017, we can conclude that as a result of the changes made during the years 2007–2017, we have a higher amount of iron-nickel alloy production [1, 2].

During the laboratory and industrial research of the production parameters analysis 1984–1997 (based on the plant archive) and the years 2007–2017, we may conclude that we analyzed the first 13 years when the ferronickel plant started operating for the first time and the 10 years when the plant started operating again [1, 4].

From the research made, it is clear that the amount of ore input in rotary kilns does not change much, varying only by a 2% increase during the period of 1984–1997; however, the amount of calcine obtained by rotary kilns is 40% higher during the years of 2007–2017, even though the higher ore input of 1984–1997 should have correlated with a higher calcine output [1, 5].

During the research, we have concluded that the low calcine output of the years 1984–1997 is a result of the high impurities which followed the ore and calcine obtained and the frequent cessation of the rotary kilns due to their inability of reaching the adequate temperatures.

From the research we obtain the main parameter of the production of the plant, Fe-Ni alloy is very high during 2007–2017. Changes made during 2007 and 2017 were the major factors in the greater benefits of Fe-Ni alloy production parameters [3].