Whole-Rock X-Ray Refraction Results for altered rock samples from Rambi gold Target Western, Kenya
Description
It measures fluorescent x-rays emitted from a sample when it's excited by a primary X-ray source. Each of the elements present in a sample produces a set of characteristic x-rays that is unique for that specific element. It is an excellent qualitative and quantitative analysis for material composition. X-RF machine is a Bruker 600N3187 Model. It is designed to quickly and accurately report the elemental analysis of samples. It is portable and set-up by connecting it to the power supply and to a computer containing the software needed to operate the device as well as print results. It is a valuable machine in identification of gemstones and other rock samples by showing their chemical composition in order to determine their names. Whole-rock XRF analysis was carried out on all 8 altered rock samples to help in their identification (where <52% Silica are mafic rocks while >52% Silica are felsic rocks. Different rock types were identified from the silica content, i.e. Sheared ultramafic rock (30.6% SiO2), Meta-basalt (49.58% SiO2) and intermediate volcanic (52.9% SiO2)
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The eight wet samples were placed in a drying oven before pulverization and crushing of the core samples. It is an important step in sample preparation to minimize contamination of samples due to remains of samples in the grinding pan which stick on surfaces as a result of moisture content in samples. The hand-held X-RF instrument was calibrated against a standard sample, quartz, in between samples. The standard sample contains known concentrations of the elements of interest. The hand-held X-RF instrument is calibrated by measuring the intensity of the signal from the standard sample and comparing it to the known concentrations of the elements. Most of the rock samples were then placed into the primary jaw crusher that was used to crush the samples to a width of about 25mm. The reduced sample size was then placed in the pulverizer and the coarse rock samples were reduced to fine powder.. A sample is placed on a sample holder then placed on the X-RF for scanning. The trigger is pulled and the analysis takes 10 seconds for Alloy mode and 30 seconds for Geo-chem mode and the results are displayed on the screen. In this case, the Geo-chem mode was used. It uses two softwares: 1. S1 Remote Ctrl: It remotely displays the controls for the Bruker S1 X-RF instrument. It enables one to edit information about sample name or ID to choose the type of analysis to be carried out from the application menu. The analysis types are: I. Alloy shavings II. Alloys: fast single phase measurement for standard alloys. III. Alloys SMART Grade (System Monitored Automatic Run Time): this application automatically determines the proper conditions and measurement times for each alloy measured. IV. Geo-chem 2. SI Sync: This software is used to download results after scanning the sample and converting them onto a printable format. It converts the original pdz format of the results to pdf format. Features include an easy to use report generator and spectrum viewer.