Hard Rock Preparation for ICP:
User Guide

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Manual Information

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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

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Introduction

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Figure 3. Sonic Bath
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.

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Drying Samples

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• Place a piece of Weigh Paper on the Base (Fig. 9).

Figure 9.

• Put one Derlin disc on top of the weigh paper (Fig. 10).

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• 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.

• Now place the second derlin disc on top of the sample (Fig. 12). Again make sure the disc rests flat against sample.

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• 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.

• 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.

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 D). The motor and pump can be heard and the pressure will rise (Fig E). 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.

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Grinding Samples in the Shatterbox

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After the last run for the day1. Take a scoop of quartz sand and put it in your vessel and run it as you would a sample for several minutes.
2. Remove the vessel and empty out the sand. Scrub the pieces with DI water and a scouring pad. Then spray with isopropyl alcohol and wipe down with Kim Wipe.
If your vessel is particularly dirty run a combination of quartz sand, a little hot water and detergent (Borax). This can be run for several minutes. A thick paste will form and you clean it with DI water and isopropyl as in the other cases.

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Making the Sample Bead

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Figure 44. Fused glass bead.

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Weighing the Sample

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Advice on LOI Procedures (from Exp. 366 Methods)

Shipboard sample preparation and LOI determination procedures described in Murray (2000) and updated in recent _IODP Proceedings_ volumes (e.g., Reagan et al. \[2015\] for Expedition 352) are appropriate for a range of sediment and rock compositions, but some care must be taken with unusual sample matrixes. As an example, attempting sample ignitions on carbonate-rich materials can lead to spurious results and issues with contamination if quartz crucibles are used for sample ignitions because carbonates will react with quartz upon heating to both devitrify and decompose the crucible. Alumina ceramic crucibles may be better for carbonates but risk contamination for Al and potentially other elements due to spallation over time. Maximum ignition temperatures of 1000°C and higher are appropriate for ultramafic and some mafic igneous materials but may result in sample sintering and/or sticking to some Si- or Ca-rich materials. Ignition temperatures of <850°C are inadequate to decompose carbonate minerals in sediment samples, even if samples are held at temperature for several hours. In general, igniting samples to at least 900°C as a maximum temperature is advisable to decompose all volatile-bearing phases and obtain reliable measures of LOI.

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Pre-ignition Weighing

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Samples are weighed on the Mettler-Toledo Dual Balance. The Dual balance uses two weighing stations to compensate for shipboard motion: one a 'known' reference weight (Fig. 30A) and the other an 'unknown' sample weight (Fig. 30B). The balance takes a series of measurements and uses the average value as the final weight (for a more in-depth guide refer to the Balance User Guide on Cumulus). Each balance has a control panel plate, which constantly record weight. These plates communicate with the "Mettler Balances" program.
Figure 30. Mettler Balance Station located in the XRay lab. A. Reference balance. B. Unknown balance. C. Sliding door. D. Reference power module. E. Unknown power module

Figure 31. Mettler Balance program window. A. Graphical measurement window. B. Final weight panel. C. Statistics panel. D. Weigh. E. Tare. F. Halt. G. Options panel. H. History panel.
Open the Mettler Balances program. This window will open. There are multiple panes and parameters that are set before we start measuring.
Graphical Measurement Window: Shows a line graph of the live-time measurement weight and the running average weight.
Final Weight Panel: Displays the Final Weight after all measurement counts have been made
Statistics Panel: Shows the average weight adjusting with time.
Counter Weight: Enter in the reference weight Counts: The elapsed amount of measurements
Tare: Shows and applies the tare or 'zero' value
Sample ID: Name the sample being measured
Commands Panel: Executable commands
Weigh: Starts measurement
Tare: Determines the 'zero' weight. This value is applied to the final weight.
Halt: Stops a measurement before it has gone through all counts
History Panel: Shows statistics on all measurements taken. This file can be exported into an excel file by using the 'Export' button. Note: The 'Export CSV' file does not work.
Options Panel: Editable measurement parameters. We measure using the 'Counts' feature. 'Counts' is active when the dot is blue. Change the number of counts or measurements the balance takes here.
At the beginning of a series of measurements, tare the balances. To do this first make sure that the 'Counter Weight' field is set to '0' and then set the 'Count' value. The 'Count' is dependent of the sea state: 600 for calm waters and 1000 counts for rough waters. If seas are too rough than wait until the weather settles before continuing to measure.
A rule of thumb is that the measurement of a known reference mass shouldn't have a larger deviation than the accuracy desired. For example, our accuracy is +/- 0.05 grams; weigh a reference mass in the unknown balance that is close to the masses you are measuring (e.g., 25 grams) and perform the measurement with the appropriate counterbalance mass in the reference balance pan. You should get a final mass of 24.95—25.05 grams.
Once parameters are set, select the 'Tare' button. When the tare is complete the 'Final Weight' Section turns orange (Fig. 32). The 'History' Section now has its first value added in (Fig. 32).
Figure 32. Mettler Balance program window showing a tare calculation.

Figure 33. Reference weights. A. Weights. B. Tweezers.
Put in a reference weight into the "Reference' balance. With the tweezers, select the 20g weight and place it in the center of the 'Reference' balance. To have a more accurate measurement, the reference weight should be close to the expected 'Unknown' sample weight (roughly ~20g).

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Weighing Crucibles

Figure 34. Crucible components. A. Outer (large) crucible. B. Inner (small) crucible. C. Lid.
Figure 35. Complete and assembled crucible unit.
The quartz crucibles have three sections: an outer (or large) crucible, an inner (or small) crucible, and a lid (Fig. 34). The inner crucible holds the sample material and is the only piece that is weighed. They are assembled as seen below with the inner crucible inside of the outer crucible and the lid sitting over the entire unit (Fig. 35). Crucible sets (large, small and lid) are engraved and lettered and should be kept as a set. For example, Crucible lid 'A' should always be run with large and small crucible 'A'. If a crucible is unlabeled use a diamond-tipped pen to etch in an unused id.

Figure 36. LOI spreadsheet.
Weight measurements are recorded in an excel spreadsheet (Fig. 36) which will be uploaded to LIMS at the end of an expedition. Open the excel spreadsheet titled 'LOI Template' found in Local Disk > DATA and save the spreadsheet in Local Disk > DATA > IN as 'EXP # LOI'.
The spreadsheet has multiple columns to fill in.'SITE', TEXT ID', 'CORE/SECT/INTERVAL', 'CRUCIBLE ID', 'CRUCIBLE WT', 'CRU+FRESH SAMPLE WT', and 'CRU+IGN SAMPLE WEIGHT'. 'SAMPLE WEIGHT', POST IGNITION LOSS', and '%LOI' are calculated values based on the weights entered in columns E – G.
The first measurement taken will be the initial weight of an empty crucible (Fig. 37). To complete this measurement, open the side door and place an empty inner crucible in the center of the 'Unknown' balance (Fig. 37). Record the number or letter etched onto the crucible in the excel spreadsheet under 'Crucible ID.'
Figure 37. Weighing an empty inner crucible.

Close the door and click 'Weigh'. Wait for the counts to finish and then record the 'Final Weight' in the spreadsheet under 'Crucible Wt'.

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Weighing Sample

Weigh out 5 grams of sample powder into the quartz crucible within +/- 0.05g (Fig. 38). The total weight should be the crucible weight + 5 grams within +/- 0.05 grams. For example, a crucible weighs 14.32g, thus the total weight plus the sample will be between 19.27 – 19.37g.
Figure 38. Crucible with approximately 5g of sample. Pre-ignition measurement
Note: If there is only a small amount of material, you can use less but the %LOI error will be larger.
When it looks like your sample is close to this range click 'Weigh.' You can always press 'Halt' to stop the measurement and either add or remove sample. If you press 'Halt' re-click 'Weigh' to take a new measurement.
When a sample's final weight is within the allowable range, record the 'final weight' value into the spreadsheet under 'CRU + FRESH SAMPLE WT'.
Carefully remove your sample from the balance. Place your crucible into the larger quartz holder and cover with a lid (Fig. 39). Repeat this process for all samples. After all samples have been weighed and recorded, take samples from the desiccator and bring over to the muffle furnace in the Chemistry Lab.
Figure 39. Complete crucible unit with sample, ready for ignition.

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Igniting Samples

Samples are ignited in the Thermolyne Muffle furnace located in the Chemistry Laboratory. The entire ignition cycle takes approximately 20 hours. After ignition, samples need to be taken out when they come down to ~ 50°C-200°C. If the samples sit for too long they will reabsorb moisture and the 'Post-Ignition Weight' will be inaccurate. Time this accordingly.

Using the Muffle Furnace

Bring crucibles over to the Muffle Furnace (Fig. 40). Turn the power switch on and the control panel will illuminate.
Figure 40. The Thermolyne Muffle Furnace. A. Power Switch B. Control Panel C. Door handle.

Confirm with scientists, what temperate and how long samples should be run for. Below is a quick reference guide (Fig. 41).

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A common program is an increase in temperature of 3°C/min to a target temperature of 900°C and a hold of one hour. Then ramp up at a rate of 3°C/min to a target temperature of 1025°C and hold for four hours. This ramp cycle is already programmed into the furnace and corresponds to 'Program 1'. To check or edit a program see additional guides attached to the furnace itself. It is also possible to run the furnace manually without a ramp up cycle. Discuss with scientists their preference
Figure 41. Control Panel on Thermolyne Muffle Furnace. A. Actual temperature. B. Desired/ Set temperature. C. Run/ stop button. D. Auto run button. E. Page button. F. Scroll button. G. Down button. H. Up button.

Either enter the desired temperature manually or select your program. If you are running the furnace manually, enter the desired temperature; no other buttons or steps are needed. If selecting a program, press and hold 'Run' (Fig. 41).
When the furnace finishes it's cycle and cools down to ~50°–200°C, remove the crucibles with tongs. Put samples onto a tray and store tray in the desiccator. Keep samples in the desiccator and remove one at a time while weighing. It is very important for the samples to not reabsorb moisture so begin weighing as soon as possible.

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Post-Ignition Weighing

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Open the Excel File 'LOI Spreadsheet Upload Template' in Local Disk > DATA (Fig. 42). Put your LOI information into the spreadsheet following the example format. Fill in the Text ID, Analysis, Replicate, Crucible number, and all weights and units including the %LOI.
Figure 42. LOI Spreadsheet Upload Template.
Open up the program 'Spreadsheet Uploader' Pinned to the Taskbar (Fig. 43).
Figure. 43. Spreadsheet Uploader Icon.

Copy and paste your spreadsheet into that uploader. Click the 'Edit' button and 'Validate Sheet'. This checks and highlights any errors that need to be fixed. When the spreadsheet comes up clean, click 'Lims' and 'Upload'. The sheet will turn green when the measurements are successfully uploaded. The data is now in LIMS under Chemistry > ICP-AES Solids >Expanded LOI.

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Cleaning the Quartz Crucibles

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Some crucibles will develop a thin white cloudy film, become spotted, or start flaking. If any of these things happen throw the crucible away in the sharps container. When the crucible undergoes one of those changes the quartz has started to react at high temperatures, and could start contaminating the sample.