Comparator neutron activation analysis of the solid volumetric rock samples for gold content
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-06-30 |
| Journal | International Journal of Biology and Chemistry |
| Authors | I.Yu. Silachyov, V.A. Glagolev |
| Citations | 6 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: MPCVD Diamond for Advanced Geochemical Analysis
Section titled âTechnical Documentation & Analysis: MPCVD Diamond for Advanced Geochemical AnalysisâExecutive Summary
Section titled âExecutive SummaryâThis research validates a robust, non-destructive method for determining ultra-low gold (Au) content in solid volumetric rock samples using Comparator Instrumental Neutron Activation Analysis (INAA) combined with X-ray Fluorescence (XRF). The success of this high-sensitivity analytical approach relies critically on precision material preparation, a core competency supported by 6CCVDâs advanced diamond materials.
- Core Achievement: Reliable determination of Au content down to the parts-per-billion (ppb) level (<0.001 ”g g-1) in volumetric rock samples (15-20 g).
- Methodology: Comparator INAA utilizing Iron (Fe) as an internal standard, determined independently by XRF.
- Precision Preparation: Samples were prepared by precision slicing drill cores with a diamond saw, eliminating the contamination and loss associated with traditional grinding and chemical digestion.
- Correction Factors Minimized: The internal standard method effectively reduced corrections for neutron self-shielding and gamma-ray self-absorption to negligible levels (<1% and <5%, respectively).
- Material Relevance: The requirement for precision, non-contaminating cutting tools highlights the necessity of high-quality Polycrystalline Diamond (PCD) material for superior diamond saw manufacturing.
- 6CCVD Value Proposition: 6CCVD provides the high-purity SCD and robust PCD materials essential for both precision tooling and advanced analytical substrates required to replicate and extend this high-sensitivity geochemical research.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the analysis of solid volumetric rock samples:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Sample Mass | 15-20 | g | Solid volumetric rock samples |
| Sample Diameter | 28.5-29.0 | mm | Puck-like cylindrical pieces |
| Sample Thickness | 9.5-10.0 | mm | Cut from rock drill-cores |
| Lowest Limit of Detection (LOD) | <0.001 | ”g g-1 | Achieved in serpentinite samples (ppb level) |
| Thermal Neutron Flux Density | 8.9 x 1013 | cm-2 s-1 | WWR-K reactor irradiation parameter |
| Fast Neutron Flux Density | 6.0 x 1012 | cm-2 s-1 | WWR-K reactor irradiation parameter |
| Irradiation Time | 1 | min | Short-timed irradiation |
| Decay Time (Pre-measurement) | 9-10 | days | To allow 24Na background decay |
| Au Analytical Gamma-line Energy | 411.80 | keV | Used for 198Au detection |
| Neutron Self-Shielding Correction (G) | <1 | % | Ratio Geff, Fe / Geff, Au close to unity |
| Gamma-Ray Self-Absorption Correction (F) | <5 | % | Ratio FFe / FAu close to unity |
Key Methodologies
Section titled âKey MethodologiesâThe experiment focused on non-destructive analysis of solid volumetric samples, emphasizing precision cutting and the use of an internal standard to simplify correction factors.
- Precision Sample Preparation: Rock drill-cores were sliced into planar cylindrical pucks (29 mm diameter, 10 mm thickness) using a diamond saw. This step was critical to avoid the gold loss and contamination associated with grinding.
- Internal Standard Selection: Iron (Fe) was chosen as the internal comparator element due to its homogeneous distribution in magmatic rocks.
- Fe Content Determination (XRF): The mass fraction of Fe was determined non-destructively using an RLP-21T energy dispersive XRF spectrometer. Samples were placed directly into the measuring chamber.
- Neutron Activation: Samples were sealed and irradiated in the WWR-K light-water reactor for 1 minute at high thermal neutron flux (8.9 x 1013 cm-2 s-1).
- Gamma-Spectrometry: After a 9-10 day decay period, samples were measured using an extended-range HPGe detector to quantify the 411.80 keV gamma-line of 198Au.
- Correction and Calculation: Gold content was calculated using the comparator INAA equation, where the internal standard (Fe) automatically accounted for neutron flux gradients and minimized corrections for self-shielding and self-absorption.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful implementation of this high-precision analytical technique relies on materials that ensure minimal contamination and high dimensional accuracy. 6CCVD provides the advanced MPCVD diamond solutions necessary for both the tooling and the analytical environment.
| Applicable Materials | Customization Potential | Engineering Support & Call to Action |
|---|---|---|
| High-Performance PCD for Tooling | Custom Dimensions & Thickness: The precision slicing of rock cores requires robust diamond tooling. 6CCVD supplies Polycrystalline Diamond (PCD) plates up to 125 mm diameter and thicknesses up to 500 ”m, ideal for manufacturing superior, long-lasting diamond saw blades and cutting wheels used in geological sample preparation. | Expert Consultation for Analytical Applications: 6CCVDâs in-house PhD team specializes in material science for high-sensitivity applications. We can assist researchers in selecting the optimal diamond grade for similar Neutron Activation Analysis (NAA) or XRF projects, ensuring minimal background interference. |
| Optical Grade SCD Substrates | Ultra-Smooth Polishing: For XRF analysis or future optical/spectroscopic methods, surface quality is paramount. 6CCVD guarantees Single Crystal Diamond (SCD) polishing with roughness Ra < 1 nm, and inch-size PCD polishing with Ra < 5 nm, providing ideal, non-contaminating analytical surfaces. | Global Supply Chain: We offer global shipping (DDU default, DDP available) to ensure rapid delivery of custom diamond materials to research facilities worldwide. |
| Custom Metalized Reference Standards | In-House Metalization: If future INAA/XRF research requires internal standards other than Fe (e.g., Pt, Au, Ti), 6CCVD offers internal metalization capabilities (Au, Pt, Pd, Ti, W, Cu) on high-purity diamond substrates, creating custom, certified reference materials. | For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. |
View Original Abstract
The application of comparator instrumental neutron activation analysis (INAA) combined with the internal standard method was considered to analyze solid volumetric samples of different rocks, 15-20 g of the mass, for Au content. Fe was used as the internal comparator with its mass fraction determined by X-ray fluorescence method (XRF) with the help of a laboratory energy dispersive XRF spectrometer RLP-21T, Kazakhstan. The puck-like samples about 29 mm across diameter and about 10 mm of the thickness were sliced up from rock drill-cores with a diamond saw. No other pretreatment was applied. Sample dimensions were fitted in compliance with that of the XRF spectrometer dishes to substitute them during analysis, i.e. they were the highest possible allowed by the spectrometer. Relative corrections for neutron self-shielding and for gamma-ray self-absorption by the samples of the same dimensions corresponding by their macrocomponent composition to the different types of common rocks turned out rather small, simply accounted using the internal standard, and almost irrespective of the rock types. By the example of serpentinite, picrite and diabase-picrite samples (Western Ulytau Belt, Central Kazakhstan) the whole approach was found as rather expedite and reliable being applied to determine Au content of sufficiently homogeneous magmatic and metamorphic rocks. More efforts resulting in Fe multiple measurements due to its heterogeneous distribution are necessary to analyze industrially significant Au contents in sedimentary rocks like black shales (Bakyrchik, Eastern Kazakhstan).