Chemical and Process Engineering Research www.iiste.org ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online) DOI: 10.7176/CPER Vol.60, 2019 39 Production of Alumina from Local Clays using Nitric and Acetic Acids Kenneth Kekpugile.Dagde * Nwankwo Chiedozie Onyebuchi Department of Chemical and Petrochemical Engineering, Rivers State University, Port Harcourt, Rivers State, Nigeria Abstract The study was carried out to investigate the effect of process variables on the production of alumina (Al2O3) by leaching of local clays obtained from four different locations in Nigeria – Ikot-Abasi, Enito II, Akpugo and Awgbu containing 56.00%, 8.45%, 25.28% and 14.43% of Al2O3 respectively. The process variables whose effect on alumina leaching investigated were: acids concentration (2M to 10M), calcinations temperature (200 o C to 1000 o C), calcinations time (15 to 75 minutes), leaching time (20 to 100 minutes) and particles size (75 to 1000µm) with the experiment conducted at constant boiling temperatures of the acids used (Nitric and Acetic acid). The recommended leaching conditions used as obtained from literature were: 6M for the two acids concentrations, particles size of 150µm, calcinations and leaching time of one hour and calcinations temperature of 600 o C. Upon leaching of these clays under prescribed conditions, the optimal yield obtained by varying each of the process variables were noted. Calcination temperature was observed to have the highest effect on the yield of alumina extractible providing the highest yield of alumina after analysis using mass adsorption spectrophotometer. The yield of alumina presented under the variation of calcination temperature were: Ikot-Abasi clay and nitric acid – yield of 68.10% alumina; Ikot-Abasi and Acetic – yield of 38.07% alumina; Enito II and nitric acid – yield of 56.50% alumina; Enito II clay and acetic acid – yield of 43.41% alumina; Awgbu clay and nitric acid – 59.04% alumina yield; Awgbu clay and acetic acid – alumina yield of 46.55%; Akpugo clay and nitric acid – alumina yield 53.47%; Akpugo clay and acetic acid – alumina yield 43.23%. It was observed that Ikot-Abasi clay/nitric acid gave the best yield. Keywords: Local Clays, Alumina, Nitric Acid, Acetic Acid, Mass Adsorption Spectrophotometer. DOI: 10.7176/CPER/60-05 Publication date:March 31 st 2019 1. Introduction In almost every part of the world, the major raw material for the manufacture of alumina has been industrial refinement of bauxite (Bayer process). Bauxite is known to contain 30-54% of aluminum oxide. The quantity of bauxite available is limited compared to its demand industrially. For the sake of conservation of resources against the backdrop of extinction, it becomes only natural to look for other means of extracting alumina from other cheaper and readily available local raw materials containing significant amount of alumina. In recent times, local clays have been the focus of these experimental studies for alumina production in which clays from Nigeria and some parts of Saudi Arabia have come under investigation (Al-Zahrani and Abdul-Majid, 2009; Ajemba and Onukwuli, 2012). Quite a number of processes have been investigated for production of alumina from kaolin and other types of clays - chiefly sintering, treatment of clays with acids or the continuous electrolysis of aluminum chloride (Austin, 1984). The French Pechiney-Ugine Kuhlmann process treats clays and shales with concentrated sulphuric acid. Hydrochloric acid is added during the crystallization step to form aluminium chloride which crystallizes readily (Barclay and Peters, 1976). In the kingdom of Saudi Arabia, kaolinitic clay obtained from Riyadh area (N: 24 00’36”, E: 47”44”03”) was subjected to leaching using hydrochloric acid. The analysis of the aluminium ion present after leaching was carried out using the solar MS Atomic Absorption Spectrophotometer. The results of their experiment showed that 62.9% of alumina present in the local clay was extracted under optimum calcinations conditions of 600 o C and 1 hour (Al-Zahrani and Abdul-Majid, 2009). Ozdemir and Cetisli, 2015 studied the extraction kinetics of alunite in sulphuric acid and hydrochloric acid in a batch reactor. The effects of reaction temperature, acid concentration, particle size, calcinations temperature, and calcinations time and aci/Al2O3 molar ratio on the extraction process were investigated. The calcinations temperature was found to be the most important parameter affecting the extraction process followed by the reaction temperature. Ajemba and Onukwuli, 2012 studied the effects of hydrochloric acid-leaching on the structural and adsorptive performance of Nteje clay in Nigeria. In their analysis, it was observed that hydrochloric acid leaching caused an exchange of Al 3+ , Fe 3+ and Mg 2+ with H + ions which led to a modification in the clay crystalline structure and caused an increase in the adsorptive capacity of the clay from 35.7% (raw clay sample) to 88.9% (leached sample with 3M HCl). brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by International Institute for Science, Technology and Education (IISTE): E-Journals