The determination of metallic iron, nickel and cobalt in reduced ores and oxides

et al. 2019

J min metall B Metall

Use of colemanite in metal-slag systems aims primarily to decrease the viscosity of slag and, therefore, achieve better metal-slag separation. Enhanced metal-slag separation is helpful to decrease the number of suspended metal/alloy droplets in slag, i.e. the physical losses. In the literature, successful use of colemanite was reported both in steelmaking and copper matte smelting processes. Ferronickel smelting slags contain nickel in the range of 0.1-0.2% and correspondingly, metal-slag distribution ratio values of nickel are reported even above 200. On the contrary, nickel recoveries are hard to exceed 95%. This can be mostly attributed to the physical losses of nickel due to very high slag volume in ferronickel smelters; for 1 ton of ferronickel, 10-15 tonnes of slag are generated regardless of the type of the laterite, which contains significant quantity of gangue components. The authors thought that use of colemanite could be a solution to decrease physical losses. Therefore, the use of colemanite in ferronickel smelting was investigated in the present work. Laboratory-scale smelting experiments were conducted using calcined and prereduced laterites in a vertical tube furnace under different gas atmospheres. The amount of colemanite added was in the range of 0-2.5% of the total charge. The experiments were also performed using ferronickel and slag samples obtained from a ferronickel smelter.

Section: Methodsmentioning

confidence: 99%

Use of colemanite in ferronickel smelting

et al. 2019

J min metall B Metall

“…In the first step, physical losses were determined by extraction of the metallic phases with bromine-methanol solution (Pournaderi et al, 2014;Kinson, Dickeson, and Belcher, 1968) and measurement of the dissolved metals by atomic absorption spectrophotometry (AAS). In the second step, the residue from the first step was dissolved in an acid mixture (HNO 3 +HCl+HF) and the solution was analysed by AAS to determine the chemical losses in the slag.…”

Section: Volume 117mentioning

confidence: 99%

Laboratory-scale smelting of limonitic laterite ore from Central Anatolia

J. South. Afr. Inst. Min. Metall.

et al. 2017

Nickel laterites are classified into three main types; saprolite, nontronite, and limonite. Of these, limonitic ores possess the lowest nickel content, ranging from 0.8 to 1.5 wt%. It is generally accepted that limonitic laterites are suitable for hydrometallurgical treatment while saprolitic laterites are suitable for pyrometallurgical treatment, i.e. ferronickel smelting. However, this perception is changing and new projects (Reinecke and Lagendijk, 2007) are aiming to treat low-grade limonitic ores by pyrometallurgical routes (Mudd, 2010) to produce ferronickel. The simplicity of the process, the nickel market, and new advances in furnace technology, as briefly discussed below, are the main incentives for smelting of limonitic laterites.Nickel in limonitic laterites is incorporated in minerals containing elements such as Fe, Co, Si, and Mg. Hydrometallurgical methods basically handle the separation of nickel from these elements through a complex process to obtain nickel in pure form (Canterford, 1975). Pyrometallurgical processing is simpler and shorter as the product contains Ni, Fe, Co, and Cu.The nickel market is the other incentive for ferronickel smelting from limonitic laterites. About 70% of this nickel output is used in iron-nickel based alloys such as stainless steels (Zevgolis, 2004), where Ni is added to the bath of molten alloy as ferronickel rather than high-priced metallic nickel. Hence separation of nickel from iron through the longer and more complicated hydrometallurgical processes is not necessary. In addition, the growing demand for ferronickel and the gradual decline in highgrade saprolitic reserves will inevitably shift the industry towards the smelting of low-grade limonitic ores in the future.Furthermore, recent advances in furnace technology (Walker et al., 2009;Voermann et al., 2004) have overcome, to a great extent, difficulties related to the smelting of limonitic ores, such as unfavourable slag composition and high CO 2 emissions. Energy costs per ton of metal have decreased, thus compensating for the low grades of limonitic ores. With current technology and nickel market conditions, ores with a nickel content of more than 1% can be treated economically (Norgate, 2010). In the future, however, higher Ni prices and new advances could lower the cut-off grades.This study investigated the feasibility of ferronickel production from a low-grade limonitic laterite ore. At the same time, it focused on the nickel losses in the slag, which is one of the major problems in ferronickel smelting. Ferronickel slags typically contain 0.1-0.2% Ni and the nickel partition ratio (percentage Ni in the ferronickel divided by percentage Ni in the slag) is about 200 or Laboratory-scale smelting of limonitic laterite ore from Central Anatolia by S. Pournaderi*, E. Keskinkılıç † , A. Geveci ‡ , and Y.A. Topkaya ‡ The feasibility of ferronickel production from a low-grade limonitic laterite ore was investigated. The ore was first calcined and then prereduced in the solid state. The reduced ore was then sme...

“…The contents of metallic iron, nickel and cobalt in the reduced samples were determined by the extraction of the metallic phases with bromine-methanol solution and the measurement of the dissolved metals using an atomic absorption spectrophotometer. 19 In a series of experiments, some reduced particles were collected before grinding and their metallographic sections were prepared for microscopic investigation by SEM/EDS.…”

Section: Reduction Experimentsmentioning

confidence: 99%

Reducibility of nickeliferous limonitic laterite ore from Central Anatolia

Canadian Metallurgical Quarterly

et al. 2013

Limonitic nickel laterite from Sivrihisar reserve in Turkey was reduced at 700-1100uC by the addition of 5?74, 8?61 and 11?48 wt-% coal under an argon atmosphere. The run-of-mine ore and the reduced samples were studied using X-ray diffraction. The metallisation of Fe was found to be limited up to 900uC, but increased rapidly at higher temperatures. The metallisation of Ni and Co increased when the temperature was increased from 700 to 800uC, almost levelled off up to 900uC and then increased up to 1100uC. The results also showed that increased coal additions did not affect Fe metallisation up to 900uC. At 1000uC the metallisation of Fe became slightly better, but its effect was more pronounced at 1100uC. The increased coal addition affected the nickel reduction equally at all temperatures, while it had no effect on the metallisation of Co.