A new method to determine composition of sphalerite without secondary pollution based on CIELAB color space

Currently, most of the methods for mineral materials analysis generate secondary pollution, which is detrimental to human health. For instance, traditional methods for sphalerite analysis in the zinc (Zn) smelting industry including chemical titration, atomic absorption spectrometry, and inductively coupled atomic emission spectroscopy. Colored indicators and toxic heavy metals are used in the analytical processes, causing severe pollution. For some methods, liquid is transformed into gaseous plasma, which is more dangerous to human health. Due to large quantities of sphalerite being used, secondary pollution cannot be ignored. This study proposes a green analysis method for the detection of sphalerite based on colorimetry, which does not generate secondary pollution. The results show that the strong substitution ability of iron (Fe) for Zn contributes to their inverse correlation in contents. The lattice parameters decrease with the increasing Fe content, resulting in a darker coloration. Here, key colorimetry parameters of L*, a*, and b* show clear linear correlations with the Zn and Fe contents. Compared with traditional approaches, this new method is environmental friendly with high sensitivity and accuracy. The relative error and relative standard deviation were less than 10% and 5%, respectively. This study provides a significant reference for nonpollution determination of other mineral materials.