Quantitative leaching of a Nigerian chalcopyrite ore by nitric acid

Abstract

Due to increasing uses of copper nitrate, Cu(NO 3 ) 2 , as catalysts, textile and polishing agents for other metals, experiment on the leaching of a Nigerian chalcopyrite ore by nitric acid for possible production of copper nitrate was examined. The effects of acid concentration, temperature and particle size on the dissolution rates of chalcopyrite ore have been investigated. Distribution of elements, compounds present within the ore particle size -90 + 75 µm was initially determined by X-ray Fluorescence (XRF), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to provide basis for explaining the dissolution process. It was observed that dissolution rates were greatly affected by acid concentration, temperature and particle diameter. Kinetic data analysis showed that the dissolution mechanism followed diffusion as the rate controlling step. The reaction order was calculated to be 0.51 while the activation energy was deduced to be 29.99 kJmol -1 from the dissolution data. The X-ray diffraction analysis of the unleached residue at optimal leaching showed that it contains α-quartz (α-SiO 2 ) and Tin oxide (SnO 2 ).

Reduction of Sulphur Content of AGBAJA Iron Ore using Hydrochloric Acid (HCL)

“…As the analyses progresses it could be observed that as the leaching time increases the percentage degree of reduction of sulphur content increases. The results obtained from the experiments agreed with [9] which observed that the percentage reduction sulphur is directly proportional to leaching time.…”

“…The removal of sulphur from iron and steel presents problems because of similarity of the standard free energies of formation of iron oxide and sulphur pentoxide [9]. Consequently, in the reducing conditions of the blast furnace to recover some 99.5% of the iron charged, near complete reduction of sulphur pentoxide from the acid blast furnace occurs.…”

“…The prevalence of this amount of sulphur is a major setback to its utilization in the blast furnace or direct reduction process [9]. The removal of sulphur from iron and steel presents problems because of similarity of the standard free energies of formation of iron oxide and sulphur pentoxide [9].…”

“…The first route employs basic slag during the conversion to steel. This technique covers the activity coefficient of sulphur pentoxide in the slag [9,10]. The second route delves into ways of reducing sulphur in the iron at relatively low temperatures.…”

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

“…Dilute acid leaching has been shown to be efficient leaching reagents. Alafara et al (2005) have quantitatively evaluated leaching dissolution of Itakpe iron ore in hydrochloric acid [7]. Adeleke et al [8].…”