The role of alkalis and conserving resources in blast-furnace smelting

Abstract

In ferrous metallurgy, the potential for conserving resources is often determined by the behavior of the impurity elements in metals production. This behavior may be highly complex, and its features may be interpretedThe special importance of alkali metals and their compounds to the running of a blast furnace has long been known.Nearly 200 years ago, in his work "Traitte de Chemia" (in the section on iron) the eminent chemist I. J. Bercellius was describing the chemical transformations that iron undergoes in metallurgical production. In so doing, he was perhaps the first to have mentioned the remarkable materials that are formed in a blast furnace and that can be seen after the furnace has been blown out. Among these materials in particular are common salt (NaCL), potassium chloride (KC1), and potassium cyanide (KCN).Since that time, the behavior of alkali metals in blast-furnace smelting has been the subject of continuous research throughout the world. The largest study of this subject in our country was the study done (1931)(1932) on the smelting of titanium-magnetite ores in blast furnaces at the Verkhne-Turinsk and Nizhniy Tagil plants with the use of coke obtained from a charge containing additions of common salt (this so-called "salt" coke contained about 5% NaCL). During the heats, from 120 to 250 kg of NaC1 entered the furnace for each ton of pig iron smelted. With the slag having had a basicity (CaO + MgO)/(SiO 2 + A1203) = 0.8 and an Na20 content of 2.8%, furnace operators could not remove more than 50 kg of sodium from the furnace. Most of it was removed through the top along with the top gases. The rest of the sodium accumulated in the furnace, rapidly destroying the lining. Nevertheless, after two trial periods of furnace operation lasting 15 and 10 days, the factories were able to smelt about 2500 tons of vanadium pig iron. M. A. Pavlov was heavily involved in the study of the behavior of alkalis in blast furnaces. In his research conducted during the 1940s, he became probably the first scientist in this country to examine the mechanism of circulation and accumulation of alkali metals during the reactions that form their cyanides and carbonates: K2CO 3 + 4C + N 2 ~ 2KCN + 3CO, Na2CO 3 + 4C + N 2 ~ 2NaCN + 3CO.Moscow State Institute of Steel and Alloys.

Mobilisation of potassium and phosphorus from iron ore by ectomycorrhizal fungi

“…High grades iron ore are usually associated with the Asbestos Hills subgroup while the medium and lower grade iron ore are found in the Campbell Rand and Gamagara subgroups, respectively (Carney and Mienie 2003). The low grade iron ore of Sishen mine has high K ([0.24%) and P ([0.03) contents that diminishes their market value and could render them non-exportable because of their negative impact on the smelting process in the blast furnace (Parks et al 1990;Yusfin et al 1999;Williams and Cloete 2008;Delvasto et al 2009). …”

Multistage dilute acid leaching of a medium grade iron ore to super-concentrate

“…The single stage leaching was carried out with about 1 g of the pre-concentrated samples (subjected to 5 minutes preliminary agitation in a 250 ml beaker and thereafter covered with aluminium foil) at 0.25 and 0.75M HCl in a 2 3 factorial design with temperatures of 30 and 90˚C and leaching contact times of 20 and 80 minutes at atmospheric pressure. Further single stage leaching were also conducted at 0.875 and 1M HCl at a temperature of 90˚C and leaching contact time of 80 minutes to determine the optimal hydrochloric acid concentration.…”

“…The ores are usually rich in iron oxides and vary in colour from dark grey, bright yellow, deep purple, to rusty red. The iron itself is usually found in the form of magnetite (Fe 3 containing46.7% of Fe). Ores carrying very high quantities of hematite or magnetite (greater than 60% iron) are known as natural ore [1].…”

Culturable microorganisms associated with Sishen iron ore and their potential roles in biobeneficiation

“…Iron ore mining companies are now faced with the challenges of refining and reprocessing low-grade iron ore minerals. Such poor quality iron ore minerals contain contaminants such as potassium, phosphorus, aluminium and sodium which are deleterious to the processing and products of this mineral (Parks et al 1990;Yusfin et al 1999;Williams and Cloete 2008;Delvasto et al 2009). …”