Chemometric quantification of trace element impurities within kaolin and talc white clay minerals in Kutch and Banas-Mahi basin, India

Abstract

The unique properties of kaolin-talc white clays such as hydration, plasticity, rheological, color, and adsorption capacities are affected by the existence of elemental/trace metal impurities. A systematic and comprehensive study regarding elemental/trace metal impurities in kaolin and talc is lacking. Thus, the present study investigated elemental impurities in kaolin and talc and their source apportionment pattern. For this concern, a total of 50 kaolin samples from the Bhuj area of the Kutch basin (Gujarat, India) and 30 talc samples from the Mahi-Banas basin of Rajasthan (Bhilwara, Udaipur, and Dungarpur) were analyzed. The major trace element impurities such as lead (Pb), chromium (Cr), copper (Cu), nickel (Ni), arsenic (As), manganese (Mn), and zinc (Zn) were detected in kaolin-talc clays from inductively coupled plasma optical emission spectrometry (ICP-OES) technique. Further, the source apportionment study was carried out by using multivariate analyses such as principal component analysis (PCA), hierarchical cluster analysis (HCA), and Pearson correlation matrix (PCM). The results indicated that the mean concentrations of trace elements Cr, Pb, Mn, Ni, Zn, Cu, and As in kaolin were 114, 57.82, 33.31, 20.36, 16.51, 10.98, and 0.05 mg/kg, respectively, whereas 2.53, 0.63, 159, 5.05, 20.11, 1.22, and 11.23 mg/kg, correspondingly, in talc samples. However, the toxic elemental impurity level was low as compared to Indian and European Union standards for soils. The present study explores the existence of major trace elemental impurities in kaolin-talc clays. Furthermore, the multivariate analyses described that the major sources of existing elemental impurities are attributed as being from different geogenic sources.