# Mineral Powder Extraction by the Natural Drying of Water from the Public Springs in Borsec
## 2 Materials and Methods
### Investigation Methods  
The water samples' physicochemical properties were measured with a HANNA HI 9829 multi-parameter measuring device (Hanna Instruments Co., Leighton Buzzard, UK). We measured the following properties: pH; electrical conductivity and resistivity; total dissolved solids (TDS); salinity; and total chloride ions. The turbidity was measured with a Hanna 93703 turbidimeter having an accuracy range of 0-1000 FTU (NTU) at a resolution of \(\pm\)5% FS. The chloride amount was measured with a photo-colorimeter HI 96711 with a measuring range of 0.00 to 2.5 mg/L for the free Cl and 0.00-3.5 mg/L for the total Cl at a resolution of 0.01 mg/L. At least three measurements were performed for each investigated parameter and the mean values were further discussed. The mean values were analyzed with Origin 6.0 software produced by Micocal Co. (Amherst, MA, USA) and plotted in graphic form. The statistical analysis was effectuated using the ANOVA test at a significance level of \(p=0.05\) followed by [PERSON]'s post-hoc test.  
The polarized light optical microscopy (POM) was performed under polarized light with crossed Nichols with a Laboval 2 Microscope (Carl Zeiss, Oberkochen, Germany) equipped with a digital image-acquiring system with a resolution of 10 mega pixels produced by Samsung Co. (Hangul, Republic of Korea). Further analysis required crystalline powder material. Therefore, the water samples were placed in Petri glasses and subjected to natural drying under ambient conditions. The crystallized crust deposits were individually scratched with a spatula and the resulting powder was placed into glass vials and further subjected to specific analyses.  
The X-ray diffraction (XRD) was effectuated on the crystalline powder samples with the Bragg-Brentano diffractometer Bruker D8 Advance produced by Bruker Company (Karlsruhe, Germany) using Cu k\(\alpha\) monochromatic radiation having a wavelength of 1.540562 A. The patterns were obtained at a speed of 1 \({}^{\circ}\)/min to ensure a proper development of the peaks including for the small contents. The peak identification was effectuated using the specialized software Match 1.0 produced by Crystal Impact Company (Bonn, Germany) using the PDF 2.0 database: aragonite 71-2396, calcite 86-2339, halite 77-2064, natron 01-0938, pseudo-dolomite (e.g., magnesium calcite) 89-1305.  
Scanning Electron Microscopy (SEM) was effectuated with a Hitachi SU8230 Scanning electron Microscope (SEM) (Hitachi Company, Tokyo, Japan) equipped with the Energy-Dispersive Spectroscopy (EDS) detector X-Max 1160 EDX (Oxford Instruments, Oxford, UK). The investigation was effectuated in the high vacuum mode at an acceleration voltage of 30 kV. The powder samples were mounted on the specimen holder using carbon double adhesive bullets and sputtered with a very thin platinum layer for ensuring proper electrical conductivity. The platinum elemental component was subtracted at the elemental analysis. The double adhesive carbon bullets might have a minor influence on the elemental composition measured over large areas and, therefore, this factor must be properly considered at the interpretation of the results.