Sina Mostaghel

Smelting of difficult laterite ores

Abstract The favourable physicomechanical characteristics of nickel have resulted in its wide application in various products, around 2m t year−1. Nickel is an essential alloying element in austenitic stainless steel and other speciality alloys. The drastic increase in production of such alloys over the last decade, mostly because of economical growth of Asian countries, particularly China, has resulted in a considerably increased demand for ferronickel. To fulfil such an expanding industrial demand, newer and more efficient routes for extraction of nickel from poorer and more difficult ores are required. The current paper summarises years of experience in designing, operating, and optimising ferronickel smelters, and describes how this knowledge can be used to develop the mitigation measures necessary to address some of the foreseeable smelting challenges associated with metal extraction from low-grade and previously undesirable laterite ores.

RECENT DEVELOPMENTS IN DRY SLAG GRANULATION: A PATH TO IMPROVING SAFETY AND SUSTAINBILITY OF THE METALLURGICAL SECTOR

Molten slag from pyrometallurgical furnaces is tapped at high temperature, carrying a large amount of thermal energy. But the common slag dumping and water granulation methods used for slag treatment do not permit energy recovery. Furthermore, water is present in these processes and while operations are designed to minimize risks of steam explosions, from the contact of slag with water, these common slag handling practices have never been inherently safe. Common handling practices do permit some slags to be sold, but often in low volumes at low prices. Dry granulation offers advantages over these common slag handling practices, including the production of by-products, the recovery of thermal energy, and the eliminated consumption and safety hazards of water. For these reasons, there have been various studies in dry granulation and heat recovery, but most have never been brought to commercial scale due to scalability and cost challenges. EcomaisterHatch has developed and brought to commercial scale a reliable and simple dry granulation and heat recovery technology. Here we review common slag handling practices, the developments in dry slag granulation over the last three decades, introduce the Ecomaister-Hatch dry slag granulation process, and elaborate on future applications of the technology in the processing of argon oxygen decarburization and blast furnace slags.

Manganese Emissions From Steelmaking

Manganese emission from pyrometallurgical furnaces is becoming an important issue with more and more stringent environmental restrictions on hazardous air pollutant (HAP) metals across the globe. Manganese is going to become the next pollutant in focus from 2016 onward. Mn emission from steelmaking or ferromanganese furnaces mainly depend on factors such as input load, gas flow rate, blowing practice, and finally the operating conditions of the dust capture systems which control particulate matter emissions. In the present study, several mechanisms of dust formation have been reviewed, and a manganese mass balance was performed to understand the distribution of Mn between liquid metal, slag, and dust for a few BOFs in operation. Operational parameters such as oxygen flow rate, blowing time, hot metal (HM) Mn content, scrap Mn content, end blow Mn%, and conditions of the electrostatic precipitator (ESP) were considered and correlated to plant measurements of Mn emission. Issues related to emissions from EAFs, ferromanganese furnaces, and high-Mn steels have been discussed as well.