Sample Preparation Laboratory

• Offer partners from research and industry, students and organizations to use our expertise and instrumentation to address problems in Earth sciences and other scientific fields.
• Provide partners from industry, researchers and students the opportunity to obtain "hands-on" experiences with our equipment and sample preparation procedures.
• Improve existing procedures and develop new protocols, tools or applications for the preparation of sample materials to be used by science and industrial research.

To be able to separate distinct minerals or fragments from rocks or hard synthetic materials, the samples are defragmented using various crushing, milling and grinding methods. Usually, the samples are subsequently sieved into different grain size fractions, dried in furnaces etc. before further sample processing or analysis are carried out.

Equipment:

• Jaw crusher

  and associated facilities for the crushing of large to cobble-sized pieces (i.e. max. width 20 cm). Max. capacity is ca. 250 kg rock material per day,
  however depends on the kind and state of the material being crushed. Rocks larger than cobbles must be broken or cut into suitable sizes prior to crushing.

• Ball mill 

  ("Pulverisette 5" from Fritsch) performs high-speed grinding of solid or liquid samples to an average fineness of < 1 μm (depending on the material being milled). The max. initial sample size for hard materials is ca. 1 cm. It is used for e.g. dry sample homogenization, materials synthesis (e.g. for pressed powder tablets) and preparation of rocks for XRF or XRD bulk chemical analyses.

• Disc mill 

  is typically used as the final-step mineral segregation before mineral grains are picked (e.g. zircons), or seperated otherwise. 
  

• Sieving facilities

  for wet and dry sieving, including routine and special setup using sieves of various mesh sizes ranging from 25 μm to 1,7 cm.

Modification of the sample material through cutting, drilling or grinding using various saws or drilling tools are carried out to adjust the sample material for further processing or analysis, e.g. for thin section puck production, epoxy mount finishing, crushing or adjustment of irregular sample sizes.

Equipment:

• Rock saws with diamond blades:
  
  • Husqvarna TC 230 F (50 mm max cutting depth)
  • Husqvarna TS 350 E (100 mm max cutting depth)
  • Minosecar II (100 mm max cutting depth)
• Struers Accutom-50 cut-off and grinding device used for fine cutting of samples and chips. Equipment for chip cuttings for thick sections.
• Various micro-cutting, micro drills and grinding tools
• Sample splitters for various grain sizes

Mineral separation using a Holman-Wilfley water shaking table is a common, rapid and high-through-put density separation method that in Earth sciences is used for extracting heavy (i.e. high density) minerals like zircon, apatite, titanite, rutile, sulfides, Fe-Ti oxides etc. from a defragmented sample.

Mineral separation applying heavy liquids is a common method used for separating high density minerals (e.g. zircon, baddelyite, apatite, rutile, titanite, sulfides, Fe-oxides etc.) from minerals of lower density (e.g. quartz, feldspar, micas etc.). We regularly use the heavy liquids Bromoform (max. density of 2.8 g/cm3) and Dimethyleneiodid (DI; max. density of 3.325 g/cm3).

Magnetic separation is a common physical method used to separate dry materials according to magnetic susceptibility, i.e. separating minerals with different magnetic properties. In Earth sciences it is most often used for extracting ferromagnetic or diamagnetic mineral fractions from igneous, metamorphic or sedimentary rocks for geochronology or geochemical analysis (e.g. Kolodner et al., 2006). For industrial purposes it is regularly used to concentrate ferromagnetic and paramagnetic ore minerals (e.g. Augusto and Martins, 1999) such as Fe-Ti oxides (e.g. ilmenite, Ti-magnetite) and Fe-Ni-Cu-sulfides or for quality control of e.g. quartz, diamond etc.

Equipment:

• LB-1 Frantz Magnetic Barrier Laboratory Separator with external regulated power supply and vibrator control units.

Production of epoxy mounts, encapsulating separated minerals, rock, slag or other types of materials and subsequent polishing is carried out on a routine basis. Typical diameter of the epoxy mounts are 10, 25 mm (~1") or 40 mm. Other sizes and shapes can be produced on request.

Equipment:

• Hot Mounting Press (Struers CitoPress-30) producing standard-sized "hot epoxy mounts" (ClaroFast resin from Struers) with diameters
  of 25 mm and of 40 mm (used e.g. for CC-SEM analysis On request, mounts with any diameter of ≤40 mm can be produced.
• Equipment for making "cold epoxy mounts" (using Epofix resin from Struers; ca. 12 hours curing time). Used e.g. for encapsulating materials sensitive to temperatures below 180⁰C.
• Struers polishing instrumentation
• Soft polishing equipment, e.g. for polishing of soft or difficult materials such as otoliths, carbonates, gold-qtz veins or other mixed "soft-and-hard" materials.

Various microscopes are used during the different sample preparation or analysis procedures to control the state of the processing and final product. For example, the final step in the separation of minerals is often picking of single mineral grains using special "picking" binocular microscopes and subsequent imaging and testing of the selected mineral grains by a scanning electron microscope. Encapsulating in epoxy and subsequent polishing of the grains are controlled by microscopes optimized for this purpose.

Equipment:

• Picking microscopes and associated tools
• Various optical microscopes
• Camera and associated equipment for optical imaging of entire rock samples and thin sections (optical microscopy lab., please contact Thomas F. Kokfelt (tfk@geus.dk). 
• Additional equipment in Optical Microscopy laboratory and the SEM laboratory

Our furnaces cover a temperature range from ambient temperature to 1250 °C. They are typically used for drying out wet sample materials, cleaning and various heating purposes, and high temperature melting of solid materials.

Equipment:

• Two high-temperature furnaces, max. 1250 °C (Struers Carbolite CSF 1100 and Heraus muffle ovens)
• Low-T furnaces (max. 300 °C) from Binder

• Hydraulic press (10 tons) for making pressed powder pellets (e.g. of otolith, carbonate or glass material used for LA-ICP-MS analysis)
• Handmagnets (goldmagnet, CONRAD magnet, magnet-pens etc.).
• Gold/heavy minerals washing pans in various sizes.
• Electronic laboratory balances with digital display and internal calibration (Mettler AK160, Sartorius BL3 and akin).
• Various heating plates used in combination with flour acid and HCL digestion of samples.
• Precision pipettes (Eppendorf, Sartorius)
• Mortars of agate and stainless steel for manually crushing and pulverizing of rocks, minerals and hard synthetic materials.
• Desiccators, Ultrasonic baths, low-P pressing devices, magnet-stirrers etc.
• Labofuge from Heraus-Christ and Certomat MO shakers from B. Braun Biotech for sample homogenization.