Question 1

What is the difference between XRF and XRD?

Accepted Answer

The two techniques are highly complementary materials analysis techniques, which when used together can can greatly improve accuracy of phase identification and quantification.
X-Ray Fluorescence (XRF) is used to identify and quantify (% or parts per million) elements, generally Fluorine (Z=9) to Uranium (Z=92), in a sample.
X-ray Diffraction (XRD) is the most accurate and direct method for identifying crystalline compounds (quartz- SiO2 , calcite- CaCO3, micas- KAl2(Si3Al)O10(OH,F)2, etc) and their concentration (%).

Question 2

Are XRD and XRF destructive to my sample?

Accepted Answer

No. However to obtain accurate and representative results, both techniques generally require a powdered sample (pulverised to approx. 50 microns or less).

Question 3

What materials can be tested?

Accepted Answer

Just about any type of solid material can be tested. Materials from naturally occuring sources i.e. soil, rock, clay, coal, etc through to industrial products such as residues, scale, cement, ceramic process materials etc. Just about anything you’re interested in.

Question 4

How much sample is required for testing?

Accepted Answer

XRD
Approximately 1 gram is usually sufficient to identify and quantify crystalline minerals. When there is a limited amount of sample available we can generally mount milligram sized samples on a low background holder.
For clay analysis we generally ask for about 20-60 grams of sample depending on the clay percentage.
XRF
Major element analysis: approximately 0.4 to 5 grams of powdered sample
Trace element and semi-quantitative analyses:  approximately 2 to 5 grams
Loss on Ignigtion (LOI): approximately 5 grams
Particle Sizing
1 to 20 grams depending on amount of particles and particle size.
Petrography
Standard thin sections have dimensions of 75 x 26 mm. A sample larger than this would be ideal (generally fist sized).

SEM
Sample size should be kept to a minimum. Chip sized samples 15mm and less are ideal.
Material needs to be able to withstand the vaccum inside the SEM.
Samples may be mounted in resin to strengthen.Samples are also coated in an electrically conductive medium to prevent negatively charged electrons from building up on the sample during analysis.

Question 5

Can you perform XRD analysis with less sample?

Accepted Answer

Yes, for the small amount of samples we have zero background sample holders which can take samples from miligram size.

Question 6

How do I submit samples?

Accepted Answer

Prior to sending samples:
   - Alert Sietronics Lab Services via email or phone that samples will be arriving
- Ensure a Purchase Order or Test Request form (undefined)is enclosed detailing sample numbers and  testing requirements.
- Ensure samples are labelled and appropriately sealed and packaged.
Samples can be sent to:
                                       Attn: Lab Manager
Sietronics Pty Ltd
40 Hoskins Street
Mitchell ACT 2911
Australia
P: +61 2 6246 9299

Question 7

How long do results take?

Accepted Answer

XRD: Generally 1-2 weeks from receipt of samples. 24-48 hour turn-around may be available upon request at additional cost.
XRF: Generally 2-3 weeks from receipt of sample
Particle Sizing: Generally 1-2 weeks
Petrology: Generally 4-6 weeks
SEM: Turn around time on application.

Question 8

Can you accept samples from overseas?

Accepted Answer

Yes!  We can accept samples from almost all countries without any issues, however to be sure please contact us before sending samples so we can advise how they should be packed, and what information needs to be included.
 
Due to recent changes by the department of agriculture, some samples require gamma irradiation upon entry to Australia.  Please contact us to discuss further.

Question 9

Can XRD always identify what's in the sample?

Accepted Answer

Most of the time. 
 
XRD can usually identify most of the phases/minerals that are present in the sample, however there are cases identifying some or all of the phases is not possible.  Particularly for samples with high amorphous content, or phases with overlaping peaks, identification can be difficult.  In these cases, additional methods such as XRF, SEM or FTIR can often aid in the identification.

Question 10

Any template reports?

Accepted Answer

Yes, go to our download page or click here(javascript:void(0))

Question 11

What method do you use to identify different clay minerals

Accepted Answer

We follow the USGS guidelines for clay mineral identification.

This includes glycolation, heat treatment to 400c and 550c.  If necessary we can differentiate kaolinite and chlorite and kaolinite and halloysite minerals.