The New Paradox of Dual Modality X-Ray Diamond Sorting

Abstract

Modern-day diamond sorting is achieved through the application of X-ray luminescence (XRL) and X-ray transmission (XRT) techniques. Sorting with XRL is limited to the class range of 1.25 mm to 32 mm because of self-absorption associated with larger diamonds, greater than 32mm. The effect of self-absorption is also a high-energy phenomenon in XRL. XRT is limited to sorting large size diamonds as the technique suffers poor contrast for diamonds smaller than 10mm. XRT measurements are immune to self-absorption for all sample sizes, while XRL measurements have good contrast for particles smaller than 32mm. The applications of these techniques have hitherto been used independently of each other and have subsequently progressed mutually exclusively. Here we analytically show a new paradox of a dual-modality X-ray diamond sorting combining XRL and XRT techniques' strengths. Key features of our new paradoxical model performance are contrast mitigation for small particles and self-absorption rejection for a large particle at high energy as well as improved particle detectability and classification.

Sensor-Based Ore Sorting—A Review of Current Use of Electromagnetic Spectrum in Sorting

“…Sensor-based ore sorting has been used in various mineral applications including diamonds, gold, copper, coal, lignite, hematite, quartz and many other minerals of value. Recently some review articles have published in the same area [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20] creating an exchange platform for cost effective engineering solutions in sensor based ore sorting. More beneficiation and advanced techniques for minerals like copper, coal, and diamond have also been proposed in [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], and [36], but none of these approaches intently reviews a generalized approach to sensor based ore sorting through the application of the interaction of electromagnetic waves with matter.…”