Õèìèÿ â èíòåðåñàõ óñòîé÷èâîãî ðàçâèòèÿ 19 (2011) 243–247 243 INTRODUCTION Columbite is the most widespread niobium mineral and makes for an important ore of the industrially useful metal [1]. Columbite, also called niobite, niobite-tantalite and columbate has a chemical formula (Fe, Mn, Mg)(Nb, Ta) 2 O 6 [2]. It is a black mineral [3] group that is an ore of niobium and tantalum. It has a submetallic luster and a high specific gravity and is a nio- bate of iron and manganese, containing tanta- late of iron while tantalite (Fe, Mn)(Ta, Nb) 2 O 6 is the most widespread tantalum mineral and also makes for an important ore of the indus- trially useful metal [4]. It is a mineral that is close to columbite, the two minerals of this series have similar properties since they have the same structure and similar chemistries. Columbite has the same composition and crys- tal symmetry (orthorhombic) as tantalite. In UDC 543 Comparison of Some Physicochemical Characterization of Columbite and Tantalite Samples from Different Locations in Nigeria OLUSHOLA S. AYANDA 1 and FOLAHAN A. ADEKOLA 2 1 Department of Chemistry, Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town (South Africa) 2 Department of Chemistry, University of Ilorin, P.M.B 1515, Ilorin (Nigeria) E-mail: holysholay04@gmail.com (Received 31.08.10) Abstract A detailed physicochemical characterization of columbite and tantalite samples from different locations in Nigeria has been undertaken. Parameters such as moisture content, loss of mass on ignition, pH, and the specific gravity of columbite and tantalite samples from different locations were determined and compared. The results showed that the moisture content of columbite samples obtained from Kwara and Plateau States are 1.0 and 0.53 %, respectively, while the percentage of moisture content of tantalite samples obtained from Kwara, Kogi, Kaduna, and Nasarawa States are 0.37, 0.30, 0.67 and 1.00 %, respectively. The percentage loss of mass on ignition of columbite samples obtained from Kwara and Plateau States and tantalite samples from Kwara, Kogi, Kaduna, and Nasarawa States are 6.1, 3.6, 7.7, 2.4, 4.4 and 4.3 %, respectively. Values of 2.40, 3.76, 3.65, 3.37, 2.07 and 1.96 were obtained as the specific gravities of columbite samples obtained from Kwara and Plateau States and tantalite samples from Kwara, Kogi, Kaduna, and Nasarawa States, respectively, and finally, the mean pH for each of columbite and tantalite samples was approximately 7.6. Keywords: columbite, tantalite, moisture content, loss of mass on ignition, pH and specific gravity fact, the two are often grouped together as a semi-singular mineral series called columbite- tantalite or coltan in many mineral guides. How- ever, tantalite has a much greater specific grav- ity than columbite, more than 8.0 compared to columbite¢s 5.2 [5, 6] and columbite is the more niobium rich end member while tantalite is the more tantalum rich end member [4, 7]. Other properties that vary slightly are colour, trans- parency and streak. Extensive columbite (niobium ore) and tan- talite (tantalum ore) reserves are found in Can a- da, Brazil, Nigeria, Zaire and Russia [8, 9]. In Nigeria, columbite samples are located in Kwara, Kadun a, Bauchi (Bauchi Plateau), Pla- teau (Bassa, Jos East, Jos South, Jos North or Riyom), Kano, Kebbi, Gombe, Abuja, Nassa- rawa and River States [10] while tantalite sam- ples are located in Kaduna (Abu hill, Gerti sta- tion or Tare Nandu), Kwara (Oro, Oke-Onig-