Quantification of Metallurgical Flux by Wavelength Dispersive X-Ray Fluorescence

This work illustrates the quantification of Fluorspar, it is commonly used during metallurgical operations as flux. In general practice it is quantified by conventional method for verification of mineralogy and grades by using 2-3 analysts and days respectively. By using conventional method analyst can estimate CaF2, CaO, SiO2, MgO and R2O3 (mixed oxides) except SrO, BaO, and P etc. due to trace low quantity. At present a new strategy / opportunity has been developed for fast, less interfering and low cost for all type of CaF2 as pressed pellet by wavelength dispersive X-ray fluorescence (WD-XRF). For verification of such strategy, a series of calibration lines were established by certified reference materials (CRM’s) and synthetic standards. Matrix effects were corrected by applied Fundamental Parameters (FP) model. In current methodology CaCO3 was calculated after analysis of total carbon (C) through Infra red combustion method. All estimations were done in dried samples after removal of moisture. CaF2 was calculated by applying mathematical formulation. The presence of CaCO3 instead of other carbonates like MgCO3, BaCO3, Na2CO3 and K2CO3 etc were confirmed by XRD, ATR-FTIR, and Volatilization method as well as compared with conventional analysis results and results were validated by using ISO-17025 protocol. *Corresponding author: Naseem Akhter, People’s Steel Mills Limited, Karachi, Sindh, Pakistan, Tel: 09202103362620599; E-mail: naseemchemist@hotmail.com Received May 28, 2018; Accepted October 15, 2018; Published October 24, 2018 Citation: Akhter N, Mumtaz M, Hussain SS (2018) Quantification of Metallurgical Flux by Wavelength Dispersive X-Ray Fluorescence. Chem Sci J 9: 195. doi: 10.4172/2150-3494.1000195 Copyright: © 2018 Akhter N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Introduction
Fluorspar is a cubic has a wide variety of applications [1][2][3][4][5]. It crystallizes as isometric cubic habit halide minerals in the form of calcium fluoride. Octahedral and more complex isometric forms are not uncommon. Element substitution for the calcium cation often includes certain rare earth elements, such as yttrium and cerium. Iron, sodium, and barium are also common impurities. Some fluorine may be replaced by the chloride anion.
Each unit cell is packed with eight F atoms and four Ca atoms and it was felt worthwhile to study the bonding between calcium and fluorine atoms ( Figure 1). In the case of fluorites, though studies on thermal vibrations, extinction, etc. have been carried out by researchers [6][7][8][9][10][11][12] the clear evidence of the bonding between metal atoms and the fluorine atoms has not been studied.
The cube samples of fluorspar were detected by XRFS, sample was prepared by fusion of Li 2 CO 3 (1.0 g) and Li 2 B 4 O 7 (5.0 g) in a Pt crucible and after addition three (03) drops of 150 g/L, LiBr solution. The mixture was fused at 1050°C for 20 min. The melt after cooling to room temperature was used for estimation of the 4 components CaF 2 , SiO 2 , Al 2 O 3 and total iron (TFe) by XRFS [13].
Calcium fluoride sample and group of standards with binder by using press powder and analyzed by an X-ray fluorescence spectrometer. Linear regression line was used for detection of samples and standards. The standards and to-be-tested sample pellets are pressed by the steps of sep. mixing the fluorite standard and to-be-tested samples with the binder, grinding, sieving with a 300-mesh sieve and pressing into a pellet using a pelletizer. The inventive method is rapid and accurate and can reduce the detection cost and improve the detection efficiency [14].
Fluorite powder was directly pressed into pellet, the total content of Ca and the contents of Fe 2 O 3 , P, SiO 2 and K 2 O were all analyzed with X-ray fluorescence spectrometry. Furthermore, the carbon content of the pellet was analyzed with IR absorption spectrometry. Based on the carbon content in the pellet, the calcium content as CaCO 3 was calculated. Then the CaF 2 content in fluorite were obtained. This method is simple and accurate. A working curve Calibration curve was made using nine certified reference material and used to test the method. In addition, the No 5# in the certified reference material series (GBW07254) was used to test the accuracy and precision of the method and the results are satisfactory [15]. Some accepts of wavelength dispersive X-ray determination of fluorine content in various matrices was estimated by Boča et al. [16]. Generally, the energy-dispersive X-ray fluorescence spectra are plotted as an equi-energy interval with the constant energy resolution. On the other hand, the wavelengthdispersive X-ray fluorescence spectra are usually measured with an equi-angle interval supposed the constant angular resolution. When the wavelength axis of wavelength-dispersive X-ray fluorescence spectra is converted into energy, the intensity should be also corrected [17].
Occasionally suggested yet rarely performed X-ray fluorescence (XRF) spectrometry of fluorine seems to fail systematically in yielding reliable quantitative results for rocks and soils. Repeated analyses reveal continuously drifting fluorescence intensities for fluorine, boron and chlorine. Typically, an increase, but in few cases also a decrease, over X-ray exposure time is observed [18].
In present attempt, the investigations were carried for the estimation and validation of all type and grades of Fluorspar. The main purpose was reduction in analysis time frame and toxicological effects with respect to classical method and analysis of minor elements which are difficult to examine accurate and precisely by classical method due to mineralogical effects and low in quantity. The potential of invented method was reconfirmed by using different primary standards, classical analyzed results and the presence of CaCO 3 (calcite) instead of other alkaline carbonates was verified by decarbonation, XRD and ATR-FTIR technologies.

Sampling location and geological study area
The CaF 2 samples were collected from different vicinity of Pakistan for verification and classification of grades and invention of methods. The fluorite of Loralai area occurs as veins and as disseminated grains along faults and fractures which is hosted by the Jurassic Loralai limestone forming the anticlinal core. Fluorite has many colors such as pink, blue, light-grey, green and light-yellow (Figures 4a-4d). Chemical analysis shows CaF 2 varies from 95.20-95.40%, CaCO 3 from 3.20-3.40% and SiO 2 from 1.40 -1.44%. Average weight % concentration of Ca is 49%, F is 45%, SiO 2 is 2.30%, CuO is 0.5%, Al 2 O 3 is 2%, Fe 2 O 3 is 0.08% and LOI is 1.47%. This type of fluorite can be used for acid preparation and also as gemstones. High grade ore (over 96% CaF 2 and less than 5% SiO 2 ) is mined from Maran and Dilband areas while low grade ore with less than 85% CaF 2 and high SiO 2 content is found at Pad Maran. The total production of fluorite during 1994-95 was about 1000 tones. Mining of fluorite is in progress in the Mekhtar (Balao, Inde, Sande and Zhizhghi), Tor Thana and Zarah areas. The estimated reserves are about 50000 tons. Attractive gem quality fluorite crystals are found in light-green, yellow and light-blue colors from Mekhtar, Wategam Zarah of Loralai district. It is also suggested that the Jurassic strata especially limestone of Kirthar and Sulaiman foldbelts and adjoining western indus suture Zone seems to be significant for further fluorite prospecting Latitude and Longitude (29° North, 66° East (est.). Neighbouring regions, Quetta district, Baluchistan Pakistan, Zhob District Balochistan province is the main producer of fluorite in Pakistan.   392 have been used including in-house synthetic standards which were prepared by combination of high purity analytical reagents of silica (SiO 2 ), calcium oxide (CaO), calcium fluoride (CaF 2 ), aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO) and ferric oxide (Fe 2 O 3 ).
Wavelength dispersive X-ray fluorescence spectrometer: WD-XRF-Philips Axios Max was used in current method for the estimation of major and minor mineralogy of CaF 2 . This instrument can be used for the determination of beryllium (Be) to uranium (U) and the level of concentrations varying by using appropriate signal and composite crystals [19]. The system used to have 3 KW Rhodium tube as X-ray generator along with other supporting determinators like channels, crystals, detector and collimators mask, initially the instrument parameters and system setup were selected as per need. After setup selection run maximum concentration samples with respect to each element for determination of angles and then adjusted analysis time, LLD (lower limit of detection) and applied background correction of each element as per requirement then same were used for pulse height distribution (PHD) determination.

Carbon sulfur analyzer calibration and estimation
Preparation of calibration standards: A series of standards were prepared by using primary standard ICRM-5132-89 having carbon content 1.41% and diluted with the help of lithium tetra borate and made series of standards of total carbon. Lithium tetra borate dried at 700°C before used.
Carbon sulfur operating mechanism: CS-800 (Eltra) analyzer was used for estimation of carbon in standards and samples, before estimation of unknown samples the instrument was calibrated with different ranges of CRMs. The said instrument is microprocessorbased instrument it can estimate a wide range of measurements, simultaneously estimate the carbon and sulfur content in metals, ores, ceramics and other inorganic materials. During this process the carbon and sulfur present in sample are oxidized to CO 2 and SO 2 and detected by infrared (IR) cell. The concentrations of unknown samples were determined relative to calibration standards. To reduce interferences from instrument drift, reference measurements of primary standards were used for verification of machine and maintained accuracy of range prior to analysis of samples.
Volatilization procedure: CaF 2 mineralogy is the major combination of CaCO 3 instead of other carbonates, for verification and presence of CaCO 3 (calcite) the volatilization tests were performed in tube furnace in the presence of helium gas with different temperatures and evaluate the loss and presence of different carbonates, for the confirmation few CRMs and samples were tested at 450, 550, 600 and 700ºC [20,21]. After said temperatures decarbonation volatilization test was not performed due to loss of fluorine at higher temperature [22].

Attenuated Total Reflection-FTIR (ATR-FTIR) for carbonates:
The Fourier-transform infrared spectroscopy (FTIR) is used for recording of spectrum in the range of 4000-400 cm -1 . Infrared measurements may perform in transmission, reflectance or attenuated total reflection (ATR) mode. For the study of different verity of materials as per their characteristics can be identifying by using different FTIR Experimental Methods Standards and samples preparation technique: Fluorspar is universal flux used during steel production for slag making. At present variety of fluorspars were analyzed by new strategy received from different country regions. Sample preparation technique is the essential part of precise and accurate development of application. Therefore, estimations of unknown samples and certified reference materials were prepared under specified conditions. These conditions were adopted for homogeneity of the samples like grinding method, grinding time, mesh size, pelletized force, time, binder type and ratio of binder. Nevertheless, before making final pressed pellets the samples were properly pulverized below 150 µm, Tyler 100 and kept in oven for loss on drying at 100-110°C for 24 hours and same procedure for drying was applied with standards and observed lose in the range of 0.001 to 0.1%. Each dried standards and samples were mixed with 0.75 g wax (binder) in zirconium grinding bowl mill for 240 second and applied 30 to 40 KN force for one minute in aluminum cup (dia 40 mm) for uniform pellets, Herzog semi automatic press was used for said purpose.
Standard materials: Calibration lines plays important role for the development of application and achievement of precise results. In present investigation, to minimize the matrix affects during initial stage of application a series of primary standards (CRMs) i-JK S9, ii-NCS DC 14023, iii-NCS DC 14025, iv-NCS DC 62003a, v-HJ-CGL 101, vi-UNS LAB Fluorite FM, vii-ICRM-5132-89, viii -JK S10, ix-BCS mA using the Cu Kα radiation). The diffractograms were automatically matched with ICDD software. Mineralogy was determined with dried samples and evaluated the present Compounds.

XRF instrument parameters
Before construction of calibration lines, the instrument parameters were selected as per requirement Table 1 shows the selection of crystals, Collimator, detector and power (combination of mA and KV) of X-ray tube. After selection of elements, angles and PHDs of each element were measured through synthetic and CRMs materials then applied offset background of channels, background calculated time and other parameters for each element. Initially, the background was estimated and subtracted from the peak area before calculation of the net peak areas. These parameters were applied to all elements as per requirement. The subtractions some time introduce large error of analysis for small peaks and gives error especially in case of minor elements ( Table 2).

XRF calibration with certified reference materials
In the current study various certified reference materials (CRMs) of fluorite were used during calibration and validation of application. For extension of lines the few CRMs were diluted with the help of lithium tetra borate (Li 2 B 4 O 7 ) and few synthetic standards prepared as per fluorspar constituents. The main mineralogy of fluorspar is consisting techniques. In daily research work the majority of people are use the surface technique is attenuated total reflection (ATR), it can be used for the determination of liquid and dried pain films [23,24]. The most of bending and skeletal vibrations are absorb in 1500-650 cm -1 region, it causes small an electronic effect in the molecule direct to large shifts. A molecule of spectrum has a hundred of absorption bands are present, but there is no need to allocate the majority of bands. These spectrums just like a fingerprint of the molecule and this region is named as fingerprint region [25].
When material is placed on crystal the IR beam penetrates the thin layer of the sample surface and losses the energy, causing the attenuated total reflection. In this technique the good contact between the sample and crystal is important [26].
The depth of penetration of the IR beam on sample depends on the IR radiation angle of incidence, redaction wavelength and refractive index of the crystal and samples. The internal reflection technique is commonly used for the nondestructive estimation of solids, powders and liquid. In current study the Thermo Nicolet is 5 FTIR with ZnSe (refractive index 2.67) was used for the investigation of fluorspar fingerprints. In present case the instrument was operated at 4 cm -1 resolution and results detected after 32 scans.

X-Ray Diffraction (XRD) analysis:
The CaF 2 mineralogy was determined by using X-ray Powder diffraction instrument PW3040/60 (Philips diffractometer, XPERT-PRO) and unit operating at 40 kV and 30

Estimation of CRMs and samples by classical method
The same standards and samples were used for the estimation by of Al 2 O 3 , MgO, total Ca, Ca (Soluble), SiO 2 , CaF 2 (by difference of total and soluble Ca) and R 2 O 3 (Fe 2 O 3 , Al 2 O 3 etc.) by ASTM-E-815 and ASTM-E-1506. BaO is difficult to estimate by conventional method (Tables 5 and 6).

Error comparisons from standards
Comparison illustrated the accuracy of current method and classical method in Table 7. Both observed values were nearest to each other and showed that current method is précised and accurate with respect to conventional method and essay to operative and demonstrative.
of SiO 2 , Fe 2 O 3 , MgO, CaCO 3 , CaF 2 as well as BaO, P, S, Na and K. The calibration lines were illustrated against concentration v/s intensity ( Figure 5) then applied theoretical correction coefficient for correction in lines and observed calibration coefficients of each element. In current application the maximum concentration range, lower limit of detection (LLD) of each element, slope of regression line, intercept of regression line and other parameters were generated during application development are mentioned in Tables 3a and 3b.

WD-XRF estimated CRMs
Standard samples were analyzed as test samples after development of application for verification and re-confirmation of known standard value (Figures 6a and 6b). The re-estimated certified reference value shows the accuracy of application present in Table 4.   iii. Ca to CaF 2 =1.95.

Alkali metal decarbonation
The presence of calcite in CaF 2 instead of other carbonates was examined at different temperatures (Table 10). The values showed that the initially loss in samples and standards was in small quantity and the maximum loss was observed at 700°C as shown in Figure 8. At 450°C the observed loss is less than the other temperatures value it confirmed the absence of MgCO 3 [27].

Mineralogical phase evaluation by XRD
The

Calibration and analysis of carbon
The total carbon of CRM's and unknown samples were analyzed by combustion method (Figure 7). The standard reference material (ICRM-5132-89, C=1.41%) was used for calibration with different dilutions showed the linearity and regression factor was R 2 =0.999 ( Table 8). The above-mentioned CRMs were used for the validation of carbon analyzer. The theoretical carbon value was calculated by CaCO 3 present in standards. The accuracy of carbon estimated value directly effects on value of CaF 2 ( Table 9).

Calculation for conversion
The following factors were used for calculation during development of application for conversion of elements:         fluorine is present in single phase compound as CaF 2. The morphology of CaF 2 also present for information at different scan ranges [28].

FTIR evaluation by ATR method
Qualitative analyses of any compound having different chemical constituents are characterized by frequencies and their characteristics. For this purpose, FTIR and XRD may be help for evaluation. In powdered samples the variety of FTIR techniques may be used for the analysis of surface. The most common technique is attenuated total reflection (ATR) (Figures 10a and 10f). In present study the ATR-FTIR was used for the presence of CaCO 3 in fluorspar, for said purpose four (04) samples and two (02) standards NCS DC-14023 and ICRM-5132-89 were selected (Table 11). The presence of bands of infrared spectrum of the Ca-CO group starching of carbonates on the 713, 875 and 1418 -1473 cm -1 it shows the absorption bands of CaCO 3 (Calcite) [29,30] and correspond to the different elongation bands of C-O. The 1418-1473 cm -1 wave numbers are the in-plane bending, 875 cm -1 wave number is the out-plan bending and 713 cm -1 wave number is an asymmetric stretching region [31]. The bands at 912-935 cm -1 , 1000-1011 cm -1 , 1031-1033 cm -1 , 1081-1187 cm -1 are belongs to SiO 2 (quartz), these are also confirmed by the presence of XRD results [32].
The strong band observed in few samples and standards at 3642-3650 cm -1 belongs to the O-H bonds (water group) to the hydroxide and characterized as water of crystallization [33]. Moreover, the bands at 777-795 cm -1 related to presence of CaF 2 [28].

Pressed Specimen Analysis Instead of Fused Bead
The said application was especially designed for all categories of fluorspar in pressed pellet specimens. Fluorine has low molecular weight and melting temperature. Because of low molecular weight of fluorine in most of the geological sample's possible losses of fluorine before calcinations and decomposes during 825°C-1330°C [34] due to evaporation before calcinations temperature it is futile to estimate by fused bead sample.

Fatal Impact on method
In the presence of other carbonates like Mg, Na, Ba, etc. instead of CaCO 3 , the current application will quantify the concentration as total carbonates, and the application has limitations to differentiate the separate carbonates as well as fatal impact on estimation of CaF 2 . But the estimated results through different techniques show that the natural occurring fluorspar has CaCO 3 and the other carbonates are present in small quantity. Therefore, the developed method has no fatal impact on determinations of CaF 2 mineralogy.

Invented method specificity
The method specificity was study by using the standards used for development and classical method for validation of application with different primary and synthetic standards concentrations. Measurement time of all elements including background correction time was 340 second. The peaks of each element showed that no specific peak overlaps demonstrating the method specificity.

Linearity and application range
Measurements of each element spectral data collected from standards were fit in linear calibration mode. The net intensity of each element was used for linear corrections and matrix absorption effects were corrected by applying fixed alpha correction method. Therefore, the Fundamental Parameter model was used for correction coefficients of each element (Tables 3a and 3b).

Method validation
Verification and implementation of new method in industry commonly use the powerful tool is Method validation. In current method the tools used for validation were standard deviation, recovery (R, %), relative percent difference (RPD, Eq. (1)), instrument detection limit (IDL), limit of quantitation (LOQ), method detection limit (MDL) and uncertainty (Ua), have been executed as significant part of the data which might be expressed the importance of biases at different concentration levels.
Al 2 O 3 , SiO 2 , Fe 2 O 3 and CaF 2 in the synthetic and certified reference materials and samples were verified using the optimized methods. Both of the mean concentration and standard deviation (SD) of the observed value for three replicates (n=3), %R, RSD, RPD have been used for accuracy measurement. IDL (expressed as 3 × SD), MDL (expressed as t × SD, where t (n-1, 1-α=0.95); t=2.92), and LOQ (expressed as 3 × SD) and uncertainty (Ua) were also estimated.
The recovery %R was the ratio of the observed concentration (Cobs) of estimated elements achieve by the optimized analytical procedure to the concentration at a reference level (Cref).
The recovery was used to test the significant departure from unity and to prove the specificity of the method optimization [35]. Therefore, it was a good practice for ion method validation to estimate R that checked sample to control bias at random duplicate withinrun precision [36]. Therefore, it was a good practice for ion method validation to estimate R that checked sample to control bias at random duplicate within-run precision [37].
IDL was used to communicate the elements present concentration identical to the electric signal of the WDXRF. Principally, this is the smallest signal that can be distinguished from the background noise of the instrument and is always laid below the MDL but does not necessary use for compliance data reporting [38]. Furthermore, it was executed to refer to the precision of the technique and the sensitivity of the instrument.
The other valuable detection limit is MDL that served statistically in human health protection and was typically used to evaluate data [38]. Otherwise, MDL is expressed as a minimum concentration of a substance that can be measured and reported with 99% confidence [38].
Even MDL does not take into account the effects of high or low bias in a series of measurements due to matrix interferences, but it was used in the current work to accomplish a relative measure of the performances of the two methods (WDXRF and classical methods for CaO, SiO 2 , Al 2 O 3 , and CaF 2 etc. measurement) for the determinations of these elements in calcium fluoride in different synthetic and reference   standards and unknown samples. LOQ which is a function to three factors: matrix, method, and analyst specificity [39].
This value is 03 × SD away from the mean as mentioned [26]. The sample concentration value (expressed as mean) that is found greater than LOQ was termed in the region of quantitation, while the concentration that belongs to the range LOQ ≥ mean ≥ IDL was expressed to be in the region of detection. Thus, LOQ was used in this study to verify a permissible limit of detection and to illustrate the smallest concentration of the element that can be consistently measured by each analytical process.
Quantification of uncertainty relevant data was analyzed considering the uncertainty associated with measurement in accordance with the EURACHEM/CITAC guide [40]. This procedure was implemented since ion analysis requires high quality of analytical data. In this work, the Guide "Measurement uncertainty arising from sampling" has been entirely adopted to facilitate the practical implementation of the technical procedure [41]. Moreover, the application of this guide clearly referred to the sources of uncertainty through the sampling, which were heterogeneous (or inhomogeneous), these were [42]. Effects of specific sampling strategy. Effects of sampling process on the sample composition of studied metals.
Therefore, present study approach to provide a practical approach for evaluating contents in CaF 2 using the concept of measurement uncertainty that enhanced both: The optimization of the analytical procedure. Design control of a sampling plan based on the repeatability of sample contribution, the application of the analytical measurement uncertainty described by EURACHEM/ CITAC was achieved. To define the stability of reading point of the ion concentration, it was decided to check the uncertainty (U A ). This term was determined through the analytical applications which were directly connected to the lack of homogeneity during sample collection.
The results of the replication process of the analytical methods based on the contents in the artificial/ synthetic reference standards. Table 12 showed good recovery values which referred that the effect of standards matrix and sample homogeneity was very critical and proved matrix influence with any of the optimized methods. Moreover, no significant difference was observed between the results obtained by the tested and the reference comparative outcomes of the reference sample for each procedure. The recovery test and the relative findings of the statistics of value had indicated a good sensitivity. On the other hand, Table 12 had defined RPD percent's, low limits of IDL, MDL, and LOQ of the optimized methods. RSD (%) values were observed in samples ranged from 0.1-2.71% and 0.0059-0.23 and in reference materials ranged from 0.027-0.73 and 0.016-0.033 for the determinations of SiO 2 and CaF 2 measured by the same classical method. The same samples and reference standards were analyzed by WDXRF and observed RSD (%) ranged in reference substance 0.014-0.047 % and 0.043-0.82, for the estimation of CaF 2 and SiO 2 respectively. In samples the RSD (%) values were estimated ranged in SiO 2 0.058-5.21 and CaF 2 0.04-0.28 (Figures 11a and 11e).
Precision and accuracy of application was depending upon the reproducibility of each element results. The accuracy of the method was investigated by determining the % accuracy standards with known number of different elements (Table 12).

Detection and quantification limits
The lower limit of detection (LLD) of each element was calculated a---------WDXRF method, b-----------Classical method NR= Not reported in certificate.    in present application depends upon the background correction time and concentration of each element to be used for calibration line development (Table 13).

Verification of invented method by proficiency test results
The developed method has been also verified by the proficiency test method. The proficiency results (Table 14) showed that invented method is applicable and accurate for determination of CaF 2 .  the following indicators (R, RSD, IDL, MDL, and LOQ) as shown in Table 12 and readability data, standard deviation and uncertainty of CRMs and samples. We can conclude that WD XRF is found the best constant readability with least uncertainty.

% Accuracy of carbon diluted standards
2. The current chosen method for estimation of fluorspar is very rapid and simple than the classical method due to difficult, engagement of 02/03 personnel and time-consuming chemical method.
3. The accuracy of the XRF method is depends upon the particle size, sample preparation and linearity of calibration curve.
4. The XRF method is validated with the help of certified reference materials which covers all range of fluorspar and validated by number of statistical tools.

Conclusion
In current study, two analytical methods are used for the estimation of Fluorspar, Classical and WDXRF. WDXRF method will be highly smart and easy to use because the suggested analytical procedure required comparatively low-cost equipment, simple to operate, with a minimum analysis of time and sample size. The instrumental approach pursued in this paper highlighted the importance of suitable sample preparation design to acquired accurate and reproducible results. For validation of XRF method, ISO/IEC 17025 protocol was followed. The drift effects in the optimized method had influenced the precision in long series of measurements. The precision involvement had been monitored using CRMs and verity of samples as shown in Table 12.
In sequence herewith, the development of such instrumental application was successfully guaranteed the principles of comparability and traceability which ensured high levels of analytical quality.
Based on the current method and confirmation the presence of CaCO 3 instead of other carbonates was proved by classical method, volatilization, XRD and ATR-FTIR methods. These findings tabulated and compared with classical method in Tables 15 and 16. In conventional method ASTM standard has no provision for the analysis of MgO, BaO, Al 2 O 3 and Fe 2 O 3 (in separate manner, ASTM report as R 2 O 3 ). By using XRF method we can estimate major and minor constituents of CaF 2 without any interference. The XRD patterns and ATR results showed the presence of CaCO 3 instead of other alkali carbonates like MgCO 3 , Br 2 CO 3 , Na 2 CO 3 , and K 2 CO 3 etc. Trend analysis of CaF 2 and SiO 2 . Figure 12 showed that both results were observed nearest to each          other, accurate and précised. Compatibility of both results showed that we can analyze any type of fluorspar by using invented method to save the human and environment hazards to the earth.
The loss of volatilization depends upon the molecular weight and order of reaction of the materials in case of carbonates the loss will observed in such protocol, MgCO 3 ˃CaCO 3 ˃Na 2 CO 3 ˃K 2 CO 3 ˃SrCO 3 ˃BaCO 3 (if all type of carbonates will present in same compound). In current study maximum loss observed at 700 ºC it confirmed the presence of CaCO 3 .
On the bases of above examinations, we can conclude that the invented WDXRF method has potential of precision, accuracy, sensitivity, reproducibility and linearity for the determination of CaF 2 and has no fatal impact on method in the presence of CaCO 3 instead of other carbonates because CaF 2 widely found as natural resources and have minimum chance for the presence of other carbonates in large quantity. However, the method is essay, ecological, beneficial, simplicity and could be used for estimation of any type and grade of CaF 2 .