From Rock to Results: Elemental Analysis in Ores

October 7, 2025

In the mining and mineral processing world, knowing exactly what is in your ore is critical. Trace elements, major constituents, impurities – they all impact process efficiency, product quality, regulatory compliance, and profitability. That’s why elemental analysis is a cornerstone of quality control, process optimization, and strategic decision-making in the mining value chain.

Why Elemental Analysis Matters?

Here are some of the major drivers for doing elemental (and sometimes isotopic) analysis:

• Grade determination & ore valuation – quantifying the content of target metals (Fe, Cu, Ni, etc.) vs gangue.
• Impurity control – e.g. sulfur, phosphorus, arsenic, etc. can poison downstream catalysts or degrade product quality.
• Process control & optimization – monitoring feed versus product streams to detect losses or inefficiencies.
• Regulatory & environmental compliance – some elements (e.g. sulfur, heavy metals) are regulated in waste streams or emissions.
• Product specification / quality assurance – for example, steel plants require strict limits on C, S, P, etc.

Because of variability in ore texture, mineralogy, and heterogeneity, sample preparation and analytical method robustness become vital.

Key Challenges in Ore Analysis

Before jumping into instrument methods, it’s helpful to recognize obstacles that must be addressed:

·         Ore samples often contain minerals of very different hardness, size, densities, and textures. Without good comminution (grinding / homogenization), spot analyses may not be representative.

·         During crushing, milling, or handling, contamination from grinding media, ambient dust, moisture, or cross-sample carryover can degrade accuracy.

·         Some target elements (e.g. S, C, nitrogen) may volatilize or migrate during preparation. For example, heating or pre-drying steps must be controlled to avoid losing analyte.

·         The presence of differing matrices (oxides, silicates, sulfides) can cause absorption or spectral interferences, requiring method-specific calibration, blank corrections, or matrix-matched standards.

·         Some elements are present only at ppm levels, which requires careful optimization of instrument sensitivity, background subtraction, and noise control.

Case Example: Iron Ore

Crushing and Grinding

Proper crushing, grinding, homogenization, and splitting are critical to ensure a representative aliquot reaches the analyzer.

• Jaw crushers for pre-crushing from 350x170 mm to 500 µm
• Ball or planetary mills are typically used to achieve fine, uniform powders, < 100 µm.
• Sample divider for representative sample splitting.

Carbon & Sulfur in Iron Ore

An ELTRA application note shows how C and S in iron ore can be precisely measured using induction furnace analyzers (e.g. CS-2000):

• Grind to ~200 µm
• Dry to constant weight
• Add iron and tungsten accelerators to ensure complete combustion
• Calibrate with certified reference materials

Typical results showed excellent repeatability (≈1–2 % RSD) for both carbon and sulfur.

Accurate elemental analysis turns raw rock into actionable information. By combining robust sample preparation with reliable instrumentation, mining labs can achieve the precision and throughput they need to stay competitive.

Click here to read the application note.