Хімічний склад і кристалічна структура природного клиноптилоліту Сокирницького родовища та його модифікованих форм

Abstract

The chemical composition of the clinoptilolite of Sokyryntsya deposit (Transcarpathian region, Ukraine) and its modified forms were investigated by X-ray fluorescence spectroscopy and SEM – EDX method. The modified forms were obtained by treatment with natural clinoptilolite (Z-0) 1M NaCl (Z-Na), HCl (ZH) solutions in a water bath at 90 °C for 8 h Аfter that they were washed with distilled water until the negative reaction to Cl– ions, the absence of which was monitored for with AgNO3 solution. Clinoptilolite (Z-Cu) was obtained after sorption of Cu2 + ions with an initial concentration of 0.02 mol/l on clinoptilolite Z-0. The grain size of clinoptilolite was 2-3 mm. The mass ratio of clinoptilolite to the solution was 1:20. Treatment of clinoptilolite with acid leads not only to ion exchange of sodium and calcium ions to hydrogen ions, but also to the extraction of aluminum from the crystal lattice of clinoptilolite. This is evidenced by a significant increase in the Si/Al ratio for clinoptilolite Z-H. When natural clinoptilolite was treated with NaCl solution, Na+ ions were exchanged mainly for double-charged calcium and magnesium ions. It should be noted that none of the proposed treatments for clinoptilolite makes it possible to completely exchange all the exchange ions. Clinoptilolite was investigated by X-ray analysis (XRD). CuKa radiation, nickel filter, in the range of 8-60 2q, in increments of 0.02 2q was used. For the clinoptilolite of composition 1.4(Na,K)2O´(Ca,Mg)O´3Al2O3´28SiO3´22H2O,a crystalchemical structure analysis was performed using the powder method using UnitCell software. Structural parameters were refined by the Rietveld method. The crystal lattice contains three sets of longitudinal grooves that are arranged in the plane (010). Two channels are parallel to the c axis: channels C1 are formed by strongly compressed ten-membered rings (inter-atomic distances 5.13´10.46 Å), and channels C2 are limited by eight-membered rings (inter-atomic distances 6.44´6.88 Å). Channels A1, parallel to the axis a [102], are also formed by eight-membered rings (inter-atomic distances 5.10´10.48 Å). The Na+ and K+ ions / atoms are preferably located in C1 channels, whereas Ca2+ (Mg2+) are located in C2 channels. The parameters of the crystall lattice of clinoptilolite (Z-0) composition 1.4(Na,K)2O´(Ca,Mg)O´3Al2O3´28SiO3´22H2O: syngony - monoclinic, space group - C12 / m1 (12), unit cell parameters - a = 17.595 Å, b = 17.593 Å, c = 7.415 Å, β = 117.01 °, V = 2044.95 Å3, Z = 1. Keywords: Clinoptilolite; сrystal structure; сhemical composition; XRF; SEM.