Kinetics of chloridization of nickel-bearing lateritic iron ore by hydrogen chloride gas

Abstract

The selective chloridization of nickel in a lateritic iron ore by gaseous HCl is based on the principle of relative thermal stability of iron and nickel chlorides. This aspect has been discussed with differential thermal analysis (DTA) and thermogravimetric (TG) data of the hydrated chlorides of iron and nickel. The kinetics of chloridization of nickel in a lateritic nickel ore from Orissa, India, have been studied by using both pure HCl (g) and the HCl (g) ϩ N 2 mixture. The sharp decrease in the rate of chloridization of nickel at temperatures above 250 ЊC is attributed to the rapid decomposition of molten ferric chloride hydrate (FeCl 3 ⅐ 3H 2 O), which blocks the pores of the reactant solid. Therefore, kinetics of chloridization follow both the pore-blocking model (logarithmic rate law) and diffusioncontrolled mechanisms. Very low values of apparent activation energy and effective diffusivity derived from the rate constants of the diffusion-controlled process suggest that diffusion of HCl (g) takes place either in a dissolved state in the molten ferric chloride (at 100 ЊC to 150 ЊC) or through cracks and fissures formed on the surface due to rapid decomposition of ferric chloride at 200 ЊC to 250 ЊC. Because of the complexity of the reaction system, the rate of chloridization of nickel is almost independent of grain size.

Vapor‐Deposited Minerals Contributed to the Martian Surface During Magmatic Degassing

“…Iron oxychloride readily picks up atmospheric moisture and can produce akaganéite (FeO (OH,Cl); Argo, 1981), a phase seen in the mudstone at Yellowknife Bay (e.g., Vaniman et al, 2014) and at Vera Rubin Ridge (Morris et al, 2019), Gale Crater, or it can produce Fe (OH) 2 Cl, even at temperatures below 100°C. Upon heating, Fe (OH) 2 Cl can lose some HCl and revert to FeO (OH,Cl), or, if all HCl is lost, form β-FeOOH (Kanungo & Mishra, 1997). Perhaps Fe (OH) 2 Cl contributed to the HCl release detected by the Sample Analysis at Mars (SAM) instrument on board the MSL Curiosity rover in Gale Crater (Hogancamp et al, 2018).…”

Kinetics of hematite chlorination with Cl2 and Cl2+O2: Part I. Chlorination with Cl2

“…[4] and [8]. It seems that carbon monoxide has little effect on the chlorination of wüstite at low temperatures during non isothermal treatment.…”

“…The extraction of these metals and / or upgrading of their ores by chlorination process depends on the amount and nature of the iron compounds content. In some cases, such as from laterites [4], jarosites [5], steel making waste dusts [6], slags from tin metallurgy [7], etc., selective separation of nonferrous metals are desirable, while in other cases, for example in the upgrading of chromite [8], bauxite [9], ilmenite [10], etc., removal of Fe as volatile chlorides has been proved to be highly beneficial. Selectivity in the processes, as mentioned above, is greatly dependent on the nature of interaction between iron oxides and different chlorinating agents.…”

Developments in physical chemistry and basic principles

“…[36][37][38] The chlorination of nickel oxide was also investigated. [39][40][41] Padilla et al 42 conducted a thermogravimetric study of the decomposition and volatilization of arsenic from enargite concentrate. Arsenic volatilized as sulfide under nitrogen and as a mixture of sulfide and oxide in 1% oxygen plus nitrogen.…”