Hard Rock Preparation for ICP:
User Guide
Manual Information
Author(s): | N. Lawler & A. Armstrong |
Reviewer(s): | C. Bennight, E. Jackson, H. Barnes |
Management Approval: | D. Houpt |
Current Version: | V371T | July 2017 | Reviewed X374 | March 2018 |
Previous Versions: | V1.2 | 6/10/2017, V1.1 | 1/6/2014 (IODP-II) |
Domain: | Chemistry; XRD lab |
System: | ICP-AES Elemental Analysis |
Keywords: | Element oxide, ICP, solids |
In This User Guide
Contents
Manual Information
In This User Guide
Introduction
Apparatus, Reagents, & Materials
Laboratory Apparatus
General Laboratory Equipment
Rock Grinding
LOI/Bead-Making
Dissolution/Dilution
Reagents
Materials
Grinding Samples
LOI/Sample Bead
Preparing Rock Samples
Cutting Samples to Size
Notes about altered samples:
Polishing Samples on Diamond Wheel
Apparatus and Materials
Cleaning Samples
Apparatus and Materials
Drying Samples
Apparatus and Materials
Crushing Samples in the X-Press
Grinding Samples in the Shatterbox
Apparatus and Materials
Cleaning the Grinding Vessels
Determining LOI
Loss on Ignition
Advice on LOI Procedures (from Exp. 366 Methods)
Pre-ignition Weighing
Apparatus and Materials
Weighing Crucibles
Weighing Sample
Igniting Samples
Post-Ignition Weighing
Uploading LOI Data To LIMS
Cleaning the Quartz Crucibles
Making the Sample Bead
Weighing the Sample
Fusing the Sample into a Bead
Using the Beadmaker
Cleaning Platinum Crucibles
Polishing the Platinum Crucibles
Using the LOI Furnace to Make Sample Beads
...
...
Introduction
Inductively Coupled Plasma Atomic Emission Spectroscopy, ICP-AES, is a method to perform elemental analysis on a sample in solution (ODP Technical Note 29). This manual covers hard rock sample preparation for ICP-AES analysis. Hard rock samples are prepared via the 'flux fusion' approach. This technique ensures complete dissolution of sample allowing a full elemental analysis. Solutions are stable which allows further analysis, and involves no HF making it a safe and ideal method (ODP Technical Note 29).
Rock samples are crushed to a fine, talc-like powder using multiple cleaning, crushing and grinding procedures. After grinding, loss on ignition (LOI) is determined. Ignited material is fused with flux powder forming a glass sample bead. Fused beads are then dissolved in 10% HNO3 . This is further diluted and the resulting solution is processed by the ICP-AES machine.
The complete process (from sample table to ICP-AES machine) takes 3-4 days. Day 1 involves: polishing on the Diamond Wheel, cleaning, and drying samples overnight. Day 2: Crushing in the X-Press, grinding in the Shatterbox, a pre-ignition (for LOI) weight, and placing samples in the furnace overnight. Day 3-4: Taking a post-ignition (for LOI) weight, and fusing the sample bead. The beads are handed off to the chemistry technicians to continue ICP analysis.
...
chemistry technicians to continue ICP analysis.
Apparatus, Reagents, & Materials
...
...
Laboratory Apparatus
...
...
General Laboratory Equipment
- Compensated Dual Analytical Balance System (Figure 1)System
- Drying ovens at 110°C and 60°C
...
Rock Grinding
- Splitting room saw
- Buehler grinder/polisher with 70 µm grit diamond grinding wheel
- Sonicator (with small water bath)
- X-Press crusher (Figure 2)crusher
- Spex Shatterbox with tungsten carbide (WC) grinding vessel (Figure 3)vessel
- Spex Mixer Mill (Figure 4)
...
- Mill
LOI/Bead-Making
- Fisher Ashing Furnace (Figure 5)Furnace
- Sample Bead Maker (Figure 6)
...
- Maker
Dissolution/Dilution
- Wrist-action shaker (Figure 7)shaker
- Acid baths (Figure 8)
...
- baths
...
Reagents
- 0.0172 mM LiBr wetting agent (0.15 mg ultrapure LiBr in 10 mL DI water)
- 10% nitric acid (143 mL concentrated nitric acid/L of solution). Caution! always add acid to water.
- Isopropyl alcohol, laboratory grade
- Methanol, laboratory grade
- Acetone, laboratory grade
- DI water (18.2 M¿ laboratory water)
...
...
Materials
...
Grinding Samples
- Beakers
- Glass cleaner
- Tweezers
- Teflon spatula
- X-Press aluminum die
- Core liner pieces and clear endcaps
- Delrin plugs
- Acid-washed 1-oz glass bottles
- Weighing paper, 6 x 6
- Kimwipes
...
LOI/Sample Bead
- Quartz crucibles
- Tongs
- Vials containing 400 mg lithium metaborate flux (preweighed on shore) (Figure 9)
- Milligram calibration weighing set
- Weighing paper, 2 x 2
- Acid-washed vials for excess ignited powder
- Agate mortar and pestle
- Pt-Ag crucibles
...
Preparing Rock Samples
Rock samples are prepared for ICP analysis using the following procedures on each sample:
- Cut to size (see Cutting Samples to Size).
- Polish (see Polishing Samples on Diamond Wheel).
- Clean (see Cleaning Samples).
- Dry (see Drying Samples).
- Crush (see Crushing Samples in the X-Press).
- Grind (see Grinding Samples in the Shatterbox).
...
...
Cutting Samples to Size
To cut samples for the X-Press, use the splitting room saw following these guidelines:
- Cut samples to ~1–2 cm in length and width. Avoid cutting irregular pieces; ideal samples are cubes. Cut the first samples small to get a feel for rock hardness.
- Avoid veins, infilled vugs, etc.
- Remove as much contaminated material as possible.
- Contact the petrologist(s) if cutting reveals unexpected features.
...
...
Notes about altered samples:
- It may be desirable to hand-pick and separate vesicles and/or veins from whole-rock basalt.
- Speak to the petrologist about this method if alteration is visible.
...
...
Polishing Samples on Diamond Wheel
To remove contamination (drill bit, saw blade, or other unwanted material) and clean the samples, grind each surface on a high-speed, diamond disc.
...
...
Apparatus and Materials
- Buehler Grinder/Polisher
- Sample Beaker
Each sample will correspond to one beaker; collect as many as needed. Beakers need to be cleaned (DI water and isopropyl alcohol) and labeled ( ex. 1, A, or sample label).
Next start the grinding process using the Buehler grinder located in the Xray prep area of the thing section lab (Fig. 1).
Note: Make sure that the correct diamond disc is attached to the wheel. The diamond disc is attached to a magnetic disc which is then placed on the wheel plate. Attach the diamond disc using either the adhesive on the back or an aluminum ring.
Figure 1: Buehler Grinder Polisher. A. On/Off switch B. Power Indicator light C. Timer On/Off button D. Water On/Off switch E. Water flow control knob F. Disc speed control. G. Stop/Start. H. Emergency Stop 
To start the polisher flip the 'On' switch in the back. The power indicator light (Fig. 1A) should illuminate. Press the timer button (Fig. 1B) to get continuous disc rotation. Turn the water on by flipping the 'Water' switch to the 'On' position (Fig. 1C). The water flow can be adjusted by turning the knob shown in Fig 1D.
The rotation speed is controlled by the dial shown in Fig. 1E. The range is 0 rpm to 500 rpm. 150 rpm is a good starting position. Adjust the speed if needed: faster for hard rocks and slower for softer rocks.
With the water on and the RPM adjusted press the 'Run' button (Fig 1F). Move the sample back and forth across the disc to prevent making a groove. If there is an emergency press the 'Emergency Stop' button (Fig. 1H) to stop rotation and cut off the water. To enable the wheel again twist the knob until it pops back out.
Polish the rocks until they're completely smooth and round on all edges. There should no pits or jagged corners. Put the rock into a labeled beaker and polish the next sample. Do this for all samples and then move on to 'Cleaning Samples'.
Figure 2. Labeled beaker with polished rock inside 
...
beaker with polished rock inside
...
Cleaning Samples
To remove contamination (oil, skin, and residue from the diamond wheel) wash the polished samples in 70% isopropyl alcohol and DI water. From this point onward, wear gloves when handling samples to avoid reintroduction of contaminants.
...
Apparatus and Materials
- Sonicator
- Beakers
- 70% Isopropyl Alcohol
- Tray(s)
Pour either DI water or isopropyl alcohol (70%) into the beaker to cover the sample. Check with the scientists for their preference in solution. There should be enough liquid to keep the sample from floating in the sonic bath (Fig.3).
Figure 3. Sonic Bath
Fill the sonic bath with a little bit of water and place beakers inside. Sonicate for 15 minutes. You should notice the water becoming cloudy from residue being shaken off the samples. Then follow the wash sequence below:
- Decant as much of the liquid as possible
- Sonicate again with DI water for 10 min.
- Decant liquid into the sink
...
Repeat the rinse cycle until the water is clear. If the samples are soft and/or clay rich, they won't reach the "clear water" state. Continuing to sonicate will only dissolve the sample. If after 3–4 washings, the water still isn't clear, go to the next step. After the final rinse, decant as much water from the beaker as possible.
...
...
Drying Samples
This step involves an overnight portion and should be done towards the end of the shift.
...
...
Apparatus and Materials
- ICP Prep Oven
- Samples
Place the beakers into the ICP Oven at 110°C for 12 hours (Fig. 5). Turn on the power button and adjust the knob to 110°C, which is marked on the oven. A thermostat is located inside to double check temperature. check temperature.
Figure 5. The ICP Prep Oven located in the X-Ray lab. A. ‘On/Off’ Switch B. Temperature Setting C. Heating Indicator
After 12 hours remove the beakers from the oven and place them inside the desiccator (Fig. 6) while you prepare the X-press station.
Note: The ICP oven should be kept clean at all times, as samples are left open and are susceptible to contamination. The ICP oven should only be used for ICP samples.
Figure 5. The ICP Prep Oven located in the X-Ray lab. A. 'On/Off' Switch B. Temperature Setting C. Heating Indicator
Figure 6. Desiccators located in the X-ray lab
...
...
Crushing Samples in the X-Press
The X-Press is a motorized hydraulic press that crushes samples into smaller pieces.
First clean the X-press with simple green and isopropyl alcohol. Clean the work area and materials with isopropyl alcohol for each sample.
Place a large KimWipe on your working surfaces for your clean materials. Next collect the following supplies that make up the 'crushing unit' of the X-press (Fig. 7). Materials are located in the drawer labeled 'X-PRESS SUPPLIES' in the X-Ray Prep Area.
Weigh Weigh Paper 6" x 6"- Core liner
- Two derlin discs
- Stainless steel base
- Figure 7: Materials needed for assembly of 'crushing unit'. A. Weigh Paper 6"x6". B. Core Liner C. Two Derlin Discs D. Stainless Steel Base E. Aluminum DieAluminum die.
Figure 7: Materials needed for assembly of ‘crushing unit’. A. Weigh Paper 6”x6”. B. Core Liner C. Two Derlin Discs D. Stainless Steel Base E. Aluminum Die
Put on gloves and 'wash' them with isopropyl alcohol. Clean the crushing supplies with isopropyl alcohol and set them down on the clean surface.
Collect sample beakers from the dessicator. Put a piece of parafilm over each beaker and bring them over to the X-press.
Now that the X-press area is clean and the samples are in the lab, assemble the crushing unit as follows:
- Grab the stainless steel dish. This is the base for the crushing unit (Fig. 8).
Figure 8.
Stainless stell dish
- Place a piece of Weigh Paper on the Base (Fig. 9).
Figure 9. Dish with Weigh paper
- Put
Put one Derlin disc on top of the weigh paper (Fig. 10).
Figure 10. Derlin Disk Added
- Place the sample on top of the Derlin Disc (Fig. 11). These discs can fracture leaving Teflon flakes in the sample so arrange the sample such that the two flattest surfaces are the top and bottom.
Figure 11.
Sample Added
- Now place the second derlin disc on top of the sample (Fig. 12). Again make sure the disc rests flat against sample.
Figure 12.
Second Derlin Disk added
- Put
Put the aluminum die on top of the derlin disk, holding it until you slip the core liner over the unit (Fig. 13).
Figure 13.
Aluminum Die added
- Now slip the piece of core liner over all the pieces and resting inside the stainless steel base (Fig. 14). This contains the sample pieces inside the unit.). This contains the sample pieces inside the unit.
Figure 14. Core Liner added
The crushing unit is now assembled and we can start crushing samples.
Figure 15: Overview of the X-Press. A. Metal platform sample rests on B. Jacksrew C. Pressure Relief Handle. D. ‘On’ toggle E. Pressure Gauge Figure 14.
The crushing unit is now assembled and we can start crushing samples.
Place the crushing unit inside the X-Press in the middle of the metal platform (Fig. 15 A). Put in the sliding polycarbonate door. Tighten the jackscrew (Fig. 15 B) until it rests firmly against the aluminum die. Tighten the 'pressure relief handle' with a clockwise turn (Fig. 15 C).
Note: The polycarbonate door sits on two interlock switches that enable operation. If the door is not fully closed or pressing down on these switches the machine will not work.
Crush the sample by continuously holding down the toggle switch (Fig 15 D). The motor and pump can be heard and the pressure will rise (Fig E15E). Once the desired pressure is reached the toggle can be released and the sample will sit under that pressure. For most samples ~5 tons of pressure is enough force to crack it. If you find the need to go past 10 tons, try rotating the sample onto another side and apply pressure again.
Note: Always wear safety glasses. Do not stand directly in front of the X-Press while it is operating. Figure 15: Overview of the X-Press. A. Metal platform sample rests on B. Jacksrew C. Pressure Relief Handle. D. 'On' toggle E. Pressure Gauge.
After the sample has cracked remove the crushing unit. To remove the unit, loosen the 'pressure relief handle' and press down on the toggle switch. The pressure gauge should read zero and the metal platform will lower down. When the platform is level with the surface let go of the toggle of start unscrewing the jackscrew. Then open the door and remove the unit. The pieces can be poured into a labeled bottle that will eventually hold the finely ground powder. From here the pieces will then be put into the Shaterbox vessels.
If pieces are still too large then repeat the same setup and crush it again. Look out for and remove any pieces of the Derlin Discs that may have chipped off and gotten into the sample.
...
Grinding Samples in the Shatterbox
The shatterbox takes the crushed pieces from the X-Press and grinds them into a very fine powder. The Spex shatterbox is capable of grinding three standard size samples or one large sample. Our grinding vessels used are tungsten carbide.
...
Apparatus and Materials
- Shatterbox
- Tungsten Carbide Vessels: Vessel, Puck, and Lid
- Samples
- 1oz Sample Vials
- Sample Labels
...
Turn on the Shatterbox by flipping the 'On' switch located on the back panel (Fig. 16A). The control panel is located on the front of the lid next to the handle (Fig. 16C).
Figure 16. Shatterbox. A. Power switch. B. Cover. C. Control panel
There are two sizes of grinding vessels: small and large. Each size has different components and requires a different setup inside the Shatterbox. The small vessel holds between 5-20 mLs of material and has three components: a container, puck, and lid (Fig. 17). 
Figure 17. Small vessel components. A. Container B. Puck. C. LidFigure 16. Shatterbox. A. Power switch. B. Cover. C. Control panel
The large grinding vessel holds between 20 – 60mLs of material and has five components: a container, puck, inner ring, O-Ring, and lid (Fig. 18). 
Figure 18. Large Vessel components.
A. Container B. Inner Ring C. Puck D. O-Ring E. Lid
The small vessels have a small indent in the bottom of the container and they will sit in the shatterbox resting on either a three pinned plate (Fig. 19) or a one pinned plate (Fig. 20).
Figure 19. Three pinned rack plate to hold three small vessels in Shatterbox
Figure 20. Single pinned rack plate to hold one small vessel in Shatterbox
The three pinned plate will hold three vessels while the one pinned plate will only hold one. If two samples need to be crushed select the three pinned plate. The large vessel will sit directly in shatterbox without an additional plate below it. Figure 20. Single pinned rack plate to hold one small vessel in Shatterbox 
Figure 19. Three pinned rack plate to hold three small vessels in Shatterbox
Loading the Shatterbox
Transfer the sample pieces into the grinding vessel. Pour sample pieces between the puck and the wall of the vessel (Fig. 21). There can't be any material on top of the puck or inside the sealing ring; otherwise the vessel will not seal properly and the sample can spill inside the Shatterbox. If any pieces are on top of the puck or ring, use gloves, tongs, or a KimWipe to move the sample into the vessel. Put on the lid and start assembling the shatterbox.
Figure 21. Small vessel filled with sample pieces. No sample material is on the top the puck or in the lid ring. 
Figure 22. The inside of the Shatterbox.
A. The lever arm B. The clamp arm C. The inner capsule Open the lid, pull out the lever arm (Fig. 22A), and pull up the clamp arm (Fig. 22B). This will reveal full access to the inner capsule (Fig. 22C).
Figure 23. Inside the Shatterbox with the bottom three pinned rack plate resting inside the inner capsule.Depending on vessel size, you will either put in the pinned plate (small vessels) or the large vessel directly. The shatterbox setup will also vary depending on sample number. If you are crushing one sample use the one pinned plate, whereas for two or three samples use the three pinned plate (Fig. 23). For crushing two samples, two vessels will be full, whereas the third will be empty without a puck. It is important to maintain balance within the machine to prevent damage.
Now load vessels onto the plate (Fig. 24). The divet in the bottom of the vessels will settle onto the pins and fit firmly in place.
Put the top rack plate over the vessels. Bring down the clamp arm (Fig. 25A). The guide on the clamp arm will settle into the boss (Fig. 25B) when centered properly.
Bring the lever arm down and push it into the end of the clamp arm (Fig. 26B). Then push the lever arm down over the clamp arm (Fig. 26A).
Figure 25. The top rack plate sitting on top of the three samples. A. Clamp arm. B. the "boss" of the rack plate, where the clamp arm will attach.Figure 24. Three samples loaded into the Shatterbox. 
Figure 26. A. The lever arm inserted into the end of the clamp arm. B. The clamp arm pushed over the lever arm.
The resistance in the lever arm is very important and must be adjusted before use. There should be moderate resistance in the arm while pushing it down. If the resistance is too low the containers can shake free; whereas, if it's too strong the clamp can break. Ideal tightness is just past the point where the vessels can be rotated while the clamp is down. Adjust the resistance by raising the clamp arm and pushing on the 'locking pin.' Hold the locking pin and turn the guide (Fig. 27A). Rotating the guide clockwise decreases resistance; whereas counterclockwise increases resistance.
Figure 27. The lever arm and the guide. A. Retractable locking pin being pushed to allow adjustment of the 'guide' length.
Now close the lid and turn the emergency stop switch to 'On'. This does not start the Shatterbox but does enable operation. If an emergency shutdown is needed, flip this switch to 'Off' and all shaking will stop even though the timer will continue to count down.
Set the grinding time. The LCD screen displays the current operating time (Fig. 28A). Adjust the time by pressing on the 'Minute' (Fig. 28B) and 'Second' (Fig. 28C) buttons. The timer maximum is 9:59.
Figure 28. A. Current operating time. B. Minute button. C. Second button. D. Start button. E. Pause/Stop button.
...