Analysis of Tantalum-Bearing Materials

Since 1982, the dramatic increase in demand for tantalum has been fueled at a rate of 10% per year by the electronics industry (Roskill Information Services). This makes tantalum a high value, high tech metal, but it is characterized by a refractory nature, low natural abundance, extensive solid solution, few known deposits, sporadic supply and difficult metallurgy.

The breadth of expertise in SGS Minerals Services allows the group to repeatedly make quality sampling and testing contributions to tantalum projects involving both naturally occurring materials and industrial products. The Group’s analytical and mineralogy laboratories in Perth, Australia and Lakefield, Canada have a wide arsenal of automated methods used to:

• Determine bulk Ta composition
• Identify Ta species present and document textural relationships
• Document the chemistry of Ta minerals and related phases

BULK COMPOSITION
Exploration materials
Low-grade solids such as soils, rocks and related geochemical exploration materials are difficult to analyze by acid-digest ICP due to the refractory nature of tantalite, and XRF due to the typically low natural tantalum abundances.

Our laboratories use fusion ICP-OES or fusion ICP-MS to ensure both a low detection limit and total analysis.

Ores, concentrates and heavy mineral separates
High-grade ore and metallurgical products are readily analyzed by automated borate fusion-XRF or ICP-OES. Borate fusion-ICP-MS can be used for low levels or impurity levels as required. This allows for a highly reproducible analysis across the wide analytical range (ppm (g/t) to over 60 wt.%) needed for low grade ores as well as tantalum concentrates.

Metals and secondary feeds
Ta-bearing metals and secondary feeds such as electronic components are first scanned to determine bulk composition and impurities. Depending on the requirements (impurity quantification vs. concentrate grades) and the matrix of the sample, multiacid or high pressure microwave digestion is then used, followed by AA, ICP-OES, or ICP-MS.

AUTOMATION AND RELIABILITY
SGS Minerals Services’ laboratories use automated sample fusion, digestion equipment and high capacity autosamplers to introduce samples to the instruments. This results in standardized procedures, reproducible operating conditions, efficient use of time, high reliability and fast turnaround.

QUALITY
Reputable labs analyze control materials to monitor their performance. Ideally, such reference materials will span both concentration range and expected sample types.

PRECISION
This control chart shows the long-term high precision that the laboratory at Lakefield has achieved on Ta. The 1σ RSD over five years is 7.3 ppm on 173 data-sets of TAN-1 by PP-XRF.

ACCURACY / BIAS
Ta determinations on certified reference materials analyzed at the laboratory in Lakefield show no bias at the 95% confidence level.

PROFICIENCY TESTING AND ROUND-ROBIN EXERCISES
The Group’s laboratories successfully participate in performance testing programs run by government and client organizations.

MINERAL IDENTIFICATION AND TEXTURES
Identification of Ta minerals is difficult due to the extensive solid solution and complex intergrowths between Ta, Nb and Fe phases so the demarcation of Ta-rich phases is often critical. The laboratory in Lakefield is uniquely positioned having a wide variety of mineralogical tools to do this, including electron microprobe, optical microscopy, image analysis, scanning electron microscopy and X-ray diffraction.

EXPERIENCE RECORD
Tantalum Exploration and Industrial Product Analyses by Borate Fusion -ICP-OES, ICP-MS, XRF, AA or Pressed Pellet -XRF SGS Minerals Services (Lakefield, Canada)

Client (Tantalum)

• Agrium
• Argento Plata Metals Limited
• Cabot
• Delphi Energy & Engine Management Systems
• Falconbridge Exploration
• Falconbridge International, U.S.
• Falconbridge Kidd Creek Metallurgical
• Falconbridge Limited Sudbury Smelter
• Falconbridge Nikkelverk A/S
• Falconbridge Technology Centre
• Mineral Assay and Services, Thailand
• Navigator Exploration Corp.
• Outokumpu Technology Inc.
• Rio Tinto
• River Gold Mines Ltd.
• Sabin Metal Corp Canada Limited
• Tantalum Mining Corp. of Canada Ltd.
• Tembec
• Tertiary (Middle East) Ltd.
• Tertiary Gold Limited

Tantalum Party Assay Determinations by Fusion-XRF SGS Analabs (Perth, Australia)
Client (Tantalum)

• Haddington International
• Sharma Brothers
• Sons of Gwalia
• Tantalum Australia  

SGS Analabs participates in round robin exercises coordinated by Sons of Gwalia for their Greenbushes and Wogina Mines.

EXPERIENCE RECORD

Projects with Significant Analytical and Mineralogical Contributions To Metallurgical Process Development for Tantalum

Ta-Nb minerals are refractory, heavy, slightly magnetic and are typically highly intergrown with sulfide and other oxide minerals. During metallurgical process development, grade, size and texture relationships must constantly be evaluated to guide the optimization of the grinding and separation strategies (e.g. gravity, magnetic intensity and flotation).
The following projects, undertaken at the SGS Minerals Services metallurgical laboratory in Lakefield, Canada, required significant analytical and mineralogical work.

Code:
lab = Laboratory test work, GRA = Gravity, MAG = Magnetic separation, FLT = Flotation, MIN = Mineralogy, ROAST = Roasting, LCH = Leaching, PPT = Precipitation, SX = Solvent extraction.