The Pyrometallurgy Best Paper Award was established by the Pyrometallurgy Section to recognize the best paper on this topic published in either the CIM Magazine, the Canadian Metallurgical Quarterly or the Conference Proceedings from the previous year. The section selects the best paper and the nominations are reviewed by the Award Subcommittee.
This award is not open to nominations from the public. The award is administered by the committee of the section of MetSoc.
H2 injection in molten metal
Author: Torben Eden, Aurubis
Presented at COM 2022, “Deep Decarbonization Pathways for Pyrometallurgical Processes: Opportunities & Challenges” symposium
The deoxidation of copper or “poling” is the final step in the pyrometallurgical process of primary and secondary copper extraction. The deoxidation generates CO2 since gaseous and liquid hydrocarbons (natural gas) are the common choice for reducing agents. Previous energy and cost saving measures increased the efficiency of the process, but the inherent production of CO2 cannot be avoided. The use of hydrogen as a reductant may decarbonise a core process of copper production, which is a desirable target for the metal industry in general and Aurubis in particular.
The primary smelter in Hamburg runs two anode furnaces with a capacity of 270 t per batch each. From September to December 2021, the anode furnaces were provisionally supplied with hydrogen and 14 batches were poled using hydrogen. These experiments were designed to determine in full scale operational tests the properties of the poling with hydrogen in terms of efficiency and process control.
The average efficiency of poling with hydrogen was higher than poling with natural gas. The adjustment of the volume flows and the temperature control of the process was always controllable. The end point of the poling with hydrogen could be determined similarly to the poling with natural gas based on the temperature curve.
The tests showed the importance of nitrogen addition for stable jetting conditions where clogging of the tuyeres was a phenomenon observed when pure hydrogen was used. An important observation from the tests was that the efficiency of the reduction was not affected by the addition of nitrogen.
This paper will discuss in detail and share the learnings of full-scale polling tests in the Hamburg anode furnace and discuss requirements for its introduction into the daily production.
Recycling Ferronickel Concentrates as an Iron Source to Extract Nickel from Nickel Sulphide Concentrates
Fanmao Wang, Sam Marcuson, Mansoor Barati and Leili Tafaghodi
Presented at COM 2021-WALSIM symposium
The conventional nickel extraction from sulphide nickel ore consists of smelting and refining, producing high purity metallic nickel products. The limit of the traditional extraction process is the significant cost of SO2 abatement, disposal of by-products (e.g., slags), and complex refining treatment. With the interest of reducing SO2 emissions and simplifying the extraction process, the authors investigated a solid-state (800 oC) thermal treatment of nickel sulphide concentrates in the presence of metallic iron under a neutral atmosphere. The results showed that approximately 97% of Ni was extracted into ferronickel (FeNi) particles with d80 = 45 µm. Recycling these FeNi particles as an iron source yielded new FeNi precipitations in the sulphide matrix with d80 = 20 µm. The Ni concentration in the resulting sulphide phase was in the range of 1–3 wt%. Optimization is required to use the recycled FeNi particles as seeds to increase the size of newly precipitated alloy particles.
Trace Element Distributions Between Matte and Slag in Direct Nickel Matte Smelting
Sukhomlinov, D., Klemettinen, L., Virtanen, O., Lahaye, Y., Latostenmaa, P., Jokilaakso, A., & Taskinen, P.
(2020) Canadian Metallurgical Quarterly, 59(1), 67-77.
Abstract: The behaviour of trace elements in the nickel matte smelting was studied at 1673 K (1400°C) by equilibration-quenching techniques followed by direct phase analyses using electron probe X-ray microanalysis and laser ablation inductively coupled plasma-mass spectrometry. The matte-slag samples at silica saturation were equilibrated with SO2-CO-CO2-Ar mixtures of fixed pSO2, pS2 and pO2 in order to obtain a pre-determined oxidation degree for the sulphide matte, and thus to
generate a targeted iron concentration of the nickel-copper–iron sulphide matte (Ni: Cu = 5, w/w), depending on the slag chemistry. The slag composition was varied from 0 to 2 wt-% K2O and 0–10 wt-% MgO in silica saturation. The studied trace elements were Co, Ge, Pb, Se and Sn, but also the matte-to-slag distributions of the slag forming fluxing components Mg (MgO) and Si (SiO2) were determined experimentally. Selenium was the only trace element studied which strongly enriched in the low-iron nickel mattes, and the deportment became larger when the sulphide matte depleted with iron. All the other trace elements behaved in the opposite way.