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Structural examinations of natural raw materials pumice and trepel from Republic of Macedonia

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The aim of this paper is to present the physic-mechanical, chemical and mineralogical-petrographic examinations of the pumice and trepel. The pumice is from deposit site called Bojanciste, near Kavadarci, and the trepel deposit is from Suvodol near Bitola, Republic of Macedonia. The mineralogical-petrographic examinations of the pumice and pumicite have shown that the main component of the pumice and pumicite it is the volcanic glass, while in the crystal phase there is presence of albit, oligoclass, anorthit, microklin and in small quantities presence of quartz, biotit and augit. The examinations of the trepel have shown that it is a sedimentary rock (of biogenic origin) with greyish-white colour, very light and soft, porous and with fine to superfine grained structure. The trepel is composed mainly of opal as well as quartz, feldspar, illite and chlorites.
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Proceedings of the XV Balkan Mineral Processing Congress, Sozopol, Bulgaria, June 12 – 16, 2013
73
STRUCTURAL EXAMINATIONS OF NATURAL RAW MATERIALS PUMICE AND TREPEL FROM
REPUBLIC OF MACEDONIA
Blagica Cekova1, Blagoj Pavlovski2 , Darko Spasev1 , Arianit Reka2
1 School of Chemistry and Technology “Maria Curie – Sklodovska”, Treta Makedonska Brigada 63a, 1000 Skopje, Republic of
Macedonia
2 Faculty of Technology and Metallurgy, University Ss. Cyril and Methodius, str Ruger Boskovic 16, 1000 Skopje, Republic of
Macedonia
ABSTRACT. The aim of this paper is to present the physic-mechanical, chemical and mineralogical-petrographic examinations of the pumi ce and trepel. The pumice is
from deposit site called Bojanciste, near Kavadarci , and the trepel deposit is from Suvodol near Bitola, Republic of Macedonia. The mineralogical-petrographic
examinations of the pumice and pumicite have shown th at the main component of the pumice and pumicite it is the volcanic glas s, while in the crystal phase there is
presence of albit, oligoclass, anorthit, microklin and in small quantities presence of quartz, biotit and augit. The examinations of the trepel have shown that it is a
sedimentary rock (of biogenic origin) with greyish-white colour, very light and soft, porous and with fine to superfine grained structure. The trepel is composed mainly of
opal as well as quartz, feldspar, illite and chlorites.
Keywords: raw materials, pumice, trepel, structural analys is
INTRODUCTION
Pumice and pumicite are porous volcanic materials. They are
created with the process of expansion of the volcanic lava that uses
the steam and the gaseous materials dissolved into the lava itself.
The pores of the pumice and pumicite can have size from a wide
range. Namely, the size of the pores can be as large as parts of
micrometre (µm) and more rough pores with sizes up to 2-3 mm. The
main difference between pumice and the pumicite is in the size of the
grains. More specifically, the material with grain size of 2 mm or
larger (up to large blocks) is classified as pumice. On the other hand,
the material with size of grains smaller than 2 mm (including the fine
dispersed material) is classified as pumicite.
The colour of pumice is grey, black and sometimes white; it
consists of silica SiO2 (up to 70%) and alumina Al2O3 (up to 15%).
Pumice occurs in fragments 5 to 50 mm across, ejected to 1400
kg/m3; porosity, 80%; compressive strength, 0.4 to 2.0 MPa;
hardness 6. (1)
Tripoli and Tripolite (diatomite) are sedimentary organogenous
rocks.
Tripoli is lightweight, clay-like rock carrying amorphous silica in the
form of fine opal balls. Its bulk density equals 500-1200 kg/m3, and
porosity 60 to 70%. (1)
Tripolite (diatomite) is a poorly cemented, very porous siliceous
rock, formed of shells of diatom algae and partly of skeletons of living
organisms. Its bulk density lies between 400 and 1000 kg/m3.
Diatomite or diatomaceous earth (also known as tripolite,
kieselguhr, infusorial earth) is a hydrous or opalscent form of silica.
The amount of water of composition seems to be variable, but usually
is between 5 and 10%. In its natural state diatomite also (usually)
contains 25 to 40% of mechanically held water, which is expelled at
100ºC. It usually contains some clay and certain types are high in
lime. Fresh-water deposits often contain organic matter that imparts
a dark-brown or almost black colour to the diatomite.
Tripoli is form of silica (SiO2) derived either from the
decomposition or alterations of chert or as a residual product from
the decomposition of a highly siliceous limestone.
Tripoli is often confused with tripolite, which is another name for
diatomite. The original tripolite from the island of Tripoli in northern
Africa was diatomaceous earth, while the term “tripoli” was first
applied to a material found near Seneca, Missouri, which somewhat
reassembled diatomaceous earth by visual inspection, but contained
no diatmos, was of entirely different origin, and had different physical
and chemical properties. The presence or absence of diatmos, when
examined under a high-power microscope, is the absolutely definite
test. Chemical analyses always show that diatomaceous earth has a
high content of combined water (5-10% or more), while Tripoli has
little or none. (2)
Experimental Section
1. Examination of pumice
The physical characteristics of pumice and pumice-pumicite from
Bojanciste, Kavadarci, Republic of Macedonia are shown in Table 1.
Tabl. 1 Physical characteristics of pumice-pumicite and
pumice
The granulometric composition of pumice-pumicite and pumice are
shown in Table 2.
Tabl. 2 Granulometric composition of pumice-pumicite and
pumice
Fraction (mm) Pumicite-pumice Pumice
- 0, 1 14,8 1,69
0,1 - 0,2 14,5 0,50
0,2 - 0,4 18,7 2,03
0,4 - 0, 8 14,5 6,45
0,8 - 2 12,3 24,14
2 - 4 11,6 19.85
- 8 8,3 25,14
+ 8 5,3 20,20
The chemical composition of the pumice-pumicite and pumice are
made by classical chemical-silicate procedure.
The chemical composition of pumice-pumicite and pumice are given
in Table 3.
Tabl. 3 Chemical composition of pumice-pumicite and pumice
Oxides Pumicite-
pumice Pumice
SiO263,73 62,65
Al2O3 17,48 17,96
F2O33,10 2,85
CaO 2,50 2,26
MgO 0,59 0,49
K2O 4,95 5,20
Na2O 4,45 3,74
SO3 -- 0,34
LOI 3,07 4,43
Total 99,86 99,92
The X-ray powder examinations (DRON, 36 kV, 10 mA, CuKα/Ni) of
pumice are shown in Figure 1.
Proceedings of the XV Balkan Mineral Processing Congress, Sozopol, Bulgaria, June 12 – 16, 2013
74
Fig. 1 X-ray diagram of pumice
From mineralogical point-of-view, pumice is similar with the
pumicite. In the samples found at this location, the main component
of the samples is volcanic glass, while in the crystal phase one can
encounter albit, oligoclass, anorthit, microcline, and in smaller
quantities quartz, biotit and augit. DTA/TG examination of the pumice
are shown in Figure 2.
Fig. 2 DTA/TG of pumice
In the sample, the most intense dehydration occurs at the
temperatures between 180 and 470ºC. With further increase of the
temperature, the dehydration process continues, however, with
decreased intensity.
2. Examination of trepel
Treated trepel deposit was discovered in the Pelagonian
depression, Republic of Macedonia, at Suvodol village near Bitola city.
According to the recent excavation mine works for coal exploitation at
the Suvodol village a peculiar geological profile was opened as
follows:
- the uppermost part is presented by agricultural soils etc. (of
alluvial-deluvial age) the thickness of which is cca 0,5 – 1.0 m;
- the lower part belongs to a biogenetic formation composed of
trepel sediments (the thickness of which is cca 50-70 m) and
coal deposits at the bottom of the abovementioned open profile.
(3)
The physical characteristics of the trepel are shown in table 4.
Tabl. 4 Physical characteristics of trepel from Suvodol, Bitola,
R. of Macedonia
A classical chemical-silicate procedure was performed for the
chemical examination of the trepel. The chemical composition of the
trepel is shown in Table 5.
Tabl. 5 Chemical composition of trepel from Suvodol, Bitola,
Republic of Macedonia
Oxides % (mass)
SiO2 64,95
Al2O3 11,85
F2O3 4,51
CaO 1,49
MgO 1,88
K2O 1,40
Na2O 0,84
SO3 1,74
LOI 11,20
Total 99,86
With X-Ray powder examination (DRON, 36 kV, 18 mA, CuKα/Ni)
in the trepel are determined: quartz, illite, feldspars, chlorites,
kaolinite, and cristobalite. The X-ray diagram of the trepel from
Suvodol, Bitola, Republic of Macedonia is shown in Figure 3.
Fig. 3 X-ray diagram of trepel from Suvodol, Bitola, R. of
Macedonia
The microscopic examinations with the polarizing translucent light
show that treated trepel sample is characterized with a micro-crypto-
crystalline ground mass of optic isotropic nature. This groundmass is
composed of opal inside of which there are very fine to superfine
grained quartz, feldspars, chlorites, illite-hydromica inclusions.
Differential thermal and thermo-gravimetrical analysis of trepel are
shown in Figure 4.
Differential thermal analysis of trepel show two exothermic peaks,
at 340ºC and 910ºC. The first exothermic peak at 340ºC is result of
oxidation of organic matter. The second exothermic peak at 910ºC is
result of crystallization of the amorphous phase in the trepel.
DTA shows also two endothermic peaks at 130ºC and 550ºC. The
first endothermic peak at 130ºC is result of loss of water and
presence of illite in the trepel. The second endothermic peak at
550ºC is result of migration of the OH-groups from the opal phase
and presence of illite in the trepel.
Characteristics Value
Density (g/cm3) 2,39-2,41
Bulk density (g/cm3) 0,64-0,88
Water absorption (%) 85-95
Total porosity (%) 68-75
Proceedings of the XV Balkan Mineral Processing Congress, Sozopol, Bulgaria, June 12 – 16, 2013
75
Fig 4. DTA/TGA of trepel from Suvodol, Bitola, Republic of
Macedonia
CONCLUSION
The examinations of pumice-pumicite and pumice from Bojanciste,
Kavadarci, Republic of Macedonia, showed that the density of
pumice-pumicite is 2,45 g/cm3 and 2,47 g/cm3 by pumice. Bulk
density of pumice-pumicite is 1,34 g/cm3 and 0,89 g/cm3 by pumice.
From the chemical and mineralogical point of view pumice-
pumicite and pumice from the deposit of Bojanciste, Kavadarci, are
similar. The main component of the pumice-pumicite and pumice is
volcanic glass, while in the crystal phase one can encounter albit,
oligoclass, anorthit, microcline, and in smaller quantities quartz, biotit
and augit.
Pumice-pumicite and pumice from deposit of Bojanciste, Kavadarci,
Republic of Macedonia can be used for production of lime-pumicite
brick with a low bulk density and good heat insulating properties.
Lime-pumicite brick are superior to clay brick because they are with a
low bulk density and better heat insulating properties. The pumice-
pumicite and pumice from the deposit of Bojanciste, Kavadarci,
Republic of Macedonia are raw materials which can be used for low
temperature synthesis of zeolite type 4A.(4)
Examined trepel sample from the Suvodol village, Bitola, Republic
of Macedonia actually represents a sedimentary rock (of biogenetic
origin) with greyish to greyish-white colour, very light and soft (1-2
by
Mohs
), fine to superfine grained structure, porous, shell-like break,
tongue sticky etc.
The X-ray and microscopic examinations show that trepel is
characterized with micro-crypto-crystalline ground mass of optic
isotropic nature. This basic mass is opal, inside of which there are
very fine to super fine grained quartz, feldspars, chlorites, illite-
hydromica inclusions.
Mineralogical and chemical composition of the trepel used in our
experiments possesses a possibility to develop a complex inorganic
technological procedure for production of zeolites, light brick,
cements etc.(5)
REFERENCES
Komar, A. (1987). Building materials and components, Moscow, Mir
Publishers.
Ladoo, R.B. (1951), Non-metallic minerals, McGraw-Hill Book
Company, Inc, New York, Toronto, London.
Pavlovski, B.
et all
(2011). Trepel – a peculiar sedimentary rock of
biogenetic origin from the Suvodol village, Bitola, Republic of
Macedonia. Geologica Macedonica, Vol 25, No 1, pp 67-72.
Cekova, B.
et all
(2012). Low temperature synthesis of 4A from
natural raw materials “pemza”, XXII Congress of SCTM, Book of
Abstracts, Ohrid 5-9 September 2012, Republic of Macedonia.
Cekova, B.
et all
(2012), Examining the possible use of natural raw
material “trepel” – Bitola for the synthesis of zeolite type 4A.
XXII Congress of SCTM, Book of Abstracts, Ohrid 5-9 September
2012, Republic ofMacedonia.
... The examined clayey diatomite from the village Suvodol is true proof of the continuity of living microorganisms (of phytogenic origin) after the sedimentation of plant products responsible for the formation of coal seams in the former Miocene-Pliocene lake basin. This sedimentary complex, composed of ash and coal, is a de facto biogenic-sedimentary formation (Pavlovski et al., 2011;Cekova et al., 2013;Reka et al., 2016Reka et al., , 2019b. ...
... X-ray clayey diatomite analysis determined: opal, quartz, illite-hydromica structures, feldspars (plagioclase, K-feldspars) and chlorites (Pavlovski et al., 2011;Cekova et al., 2013). ...
Chapter
This paper compares the percentage of removal of Cr(VI) ions from aqueous solutions with pure diatomite and clayey diatomite. To characterize the adsorbents, the following analyses were performed: classical silicate chemical, differential thermal and thermogravimetric, X-ray dispersive, Fourier transform infrared, scanning electron microscopy, and transmission electron microscopy. The Brunauer–Emmett–Teller model (as, m2/g) was used to determine the specific area. Atomic absorption spectrophotometric method and UV/Vis spectrophotometric analysis were used to determine the concentration before and after the Cr(VI) adsorption process. A series of experiments was performed to determine the point of zero charge. The influence of pH was also examined, and we obtained the best results at low pH values. At an initial concentration of Cr(VI) ions of 0.5 mg/L and a pH equal to 2, the best results were shown by the clayey diatomite, where the percentage of removal is 100%, while the diatomite is 28%. So the used natural raw material clayey diatomite at low cost is an effective adsorbent for the removal of Cr(VI) ions.
... For biochar, this is particularly the case when produced from woody material (Waldron 2014). The porosity of pumice (64-85% by volume) is generated by air bubbles created during its formation, which give this material a low bulk density (0.35-0.65 g cm −3 ), and large pore-size span (from micrometre to millimetre) (Ersoy et al. 2010;Cekova et al. 2013). The physical properties of biochar mainly depend on the type of feedstock, which is influenced by the plant cellular structure, plus the type of pyrolyser, highest heating temperature of pyrolysis, residence time (Rasa et al. 2018) and activating agents. ...
... Lënda e parë që është marë për analizë është nga regjioni i Mariovës. Materiali është një shkëmb me ngjyrë të zbehtë, i lehtë, i butë, lehtë i thyeshëm, dendësi të ulët specifike, porozitet të lartë, përcueshmëri të vogël termike dhe me një potencial të madh për përdorim në industri [7][8][9][10][11][12][13] . Në figurën 10 kemi pamjen makroskopike të lëndës së parë. ...
... Diatomiti është i njohur gjithashtu si tokë diatomike dhe "kieselguhr" në Evropë, në të kaluarën ajo njihej gjithashtu si tripolit [12,38] . Tokë diatomike (DE) përdoret veçanërisht kur diatomiti është në formë të pluhurit [32] . ...
... Smaller quantities of DE were mined in 23 other countries [35]. North Macedonia fits in this group being rich in DE and other silica-based materials (trepel, perlite, pumice, etc.) [36][37][38][39][40][41][42] with a wide scope of potential utilization and application. The economic benefit of using DE from North Macedonia is based on its fine microstructure and, more importantly, because of the presence of non-crystalline (amorphous) phase. ...
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The diatomaceous earth (DE), collected from the Mariovo region in North Macedonia, was characterized and thermally modified. The material represents a sedimentary rock of biogenic origin, soft solid that can be easily disintegrated, with white to grayish color, with bulk density of 0.51–0.55 g/cm3, total porosity of 61–63%, and specific gravity of 2.25 g/cm3. The chemical composition is as follows: SiO2, 86.03; Al2O3, 3.01; Fe2O3, 2.89; MnO, 0.06; TiO2, 0.20; CaO, 0.76; MgO, 0.28; K2O, 0.69; Na2O, 0.19; P2O5, 0.15; and loss of ignition, 5.66 (wt%). The mineralogy of the raw DE is characterized by the predominant presence of amorphous phase, followed by crystalline quartz, muscovite, kaolinite, and feldspar. Significant changes in the opal phase are observed in the 1,000–1,200°C temperature region. At 1,100°C, the entire opal underwent solid–solid transition to cristobalite. Further ramp of the temperature (1,100–1,200°C) induced formation of mullite. Scanning electron microscopy (SEM) and transmission electron microscopy depict the presence of micro- and nanostructures with pores varying from 260 to 650 nm. SEM analysis further determined morphological changes in terms of the pore diameters shrinkage to 120–250 nm in comparison to the larger pores found in the initial material. The results from this investigation improve the understanding of mechanism of silica phase transition and the relevant phase alterations that took place in DE upon calcination temperatures from 500 to 1,200°C.
... Republic of North Macedonia is rich in natural inorganic materials such as clayey diatomite (Pavlovski et al. 2011;Cekova et al. 2013;Reka et al. 2016Reka et al. , 2019b, perlites (Reka et al. 2019a), and diatomite (Reka et al. 2014) that represent industrial minerals which could be used to successfully remove various metal ions from aqueous solutions. ...
Chapter
The clayey diatomite from the village of Suvodol (Bitola region) used in this research has shown to be a very effective and efficient natural material for the removal of Cr(VI) ions from aqueous solutions. The adsorption of Cr(VI) ions onto a clayey diatomite was shown to occur very efficiently with 96.7%. During the experiments the effect of operating parameters, such as amount of adsorbent (0.5–5.5 g/l), initial adsorbate concentration (0.3, 0.4, 0.5, and 0.6 mg/l), and time of adsorption (5–180 min) at pH of the solution 3, was examined. It was found that 2.5 g/l is optimal adsorbent dosage for maximal removal of Cr(VI) ions. Atomic absorption spectrophotometric (AAC) method and UV-Vis spectrophotometric analysis are used for quantitative monitoring of the dynamics of the studied system regarding the presence of Cr(VI) ions in the model solutions. The effect of the initial concentration and quantity of adsorbent is examined, in order to determine the conditions that enable maximum removal of Cr(VI) ions with clayey diatomite. For the purpose of modeling the equilibrium, the kinetics, and dynamics of the tested system of the process of elimination of Cr(VI) ions with the raw material in different operating conditions, MATLAB/Curve Fitting Toolbox was conducted.
... The sorption of heavy metal ions onto raw or modified diatomite in wastewater was previously studied [10,[23][24][25][26][27], and the results show that diatomite is a promising material for dealing with environment contamination. The use of powdered diatomite earth in filtration, is now widespread [13,28]. A number of works consider diatomite as a promising sorbent in relation to uranium [9,10], but a significant part of such studies is devoted to studying sorption on modified samples. ...
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This investigation made it possible to compare the sorption capacity of mineral and organic sorbents in respect to U(VI). In order to establish the patterns of sorption, natural sorbents with a high content of rock-forming mineral were used: glau-conite, diatomite, zeolite, peat, brown and hard coals, shungite. Each sample was characterized using X-ray diffraction, X-ray fluorescence method, scanning electron microscope, XPS spectra, potentiometric acid-base titration and surface area measurement. The partitioning of U(VI) was determined by sequential extraction technique. It was shown that the highest sorption ability and strongest interaction towards U(VI) is common to peat and brown coal.
... Chemical composition of the soil samples is determined by silicate chemical analysis. The existing minerals in soil have been identified by X-ray analysis, on Rigaku Ultima IV diffractometer [10][11][12][13][14][15][16][17]. pH value of soil samples is measured from 30% water suspension on pH meter Sartorius. ...
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Research relevance. Most ground movements are generally due to rock instability, this natural phenomenon poses a risk to humanity. The properties of the rock mass directly influence the type of movement especially in underground structures. Research aim. Our goal is to characterize and classify the rock mass of diatomite from the sig mine using geomechanical classification systems such as the RQD and RMR in order to determine the quality of the rocks in the sig mine Western Algeria from the determination of the physical and mechanical properties. Methodology. In this article, the characterization analysis of the diatomite rock mass of the sig mine was carried out. First, determinations of the physical properties and carried out the triaxial test to determine the mechanical properties (young's modulus, the friction angle, the dilatancy angle, the cohesion, the poisson's ratio). Secondly to classify the deposit and give a recommendation to avoid stability problems. Research results. The results from physical and mechanical analyzes, it can be said that the nature of the rock present in the diatomite (underground mine) does not have enough resistance. Conclusion. Our study definitively proves that the rock mass of sig diatomite is of very low quality and it will be very dangerous for the underground mining work of the mine especially in places where the mineralized layer is very deep. And we suggest to replace the mining technique room and pillar currently used in the diatomite mine and put another mining method which includes roof support system to ensure the safety both of the miners and the equipment.
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Streptococcus mutans (S. mutans) has been identified as a major etiologic agent of human dental caries and forms a significant proportion of oral strepto-cocci in carious lesions. This study investigates the correlation of surface properties (effect of contact angle [CA] and free surface energy) on three restorative materials (zirconia, nickel-chromium-molybdenum alloy and composites) used in dental prosthetics with bacterial adhesion to S. mutans. Ten samples of each material (zirconia, nickel-chromium-molybdenum alloy and composites) of 8 mm diameter and 2.5 mm thickness were used. Aqueous CA measurements, free surface energy and bacterial adhesion to the sample surfaces were performed. Bacterial adhesion is determined by planting samples in the blood agar cultures and using an electron microscope (scanning electron microscopy [SEM]). The highest values of bacterial adhesion are found in composites, followed by the metal alloy, while the lowest values are observed in zirconia. Measurements show that zirconia has 17 bacteria; Ni-Cr-Mo alloy has 65, while the composite has 80 bacteria. The composites showed the highest degree of bacterial adhesion, compared to the other investigated materials, which correlates with the free surface energy of the samples (24.31 mJ/m 2 for zirconia, 31.78 mJ/m 2 for Ni-Cr-Mo alloy and 48.82 mJ/m 2 for the composite).
Trepel-a peculiar sedimentary rock of biogenetic origin from the Suvodol village
  • B Pavlovski
Pavlovski, B. et all (2011). Trepel-a peculiar sedimentary rock of biogenetic origin from the Suvodol village, Bitola, Republic of Macedonia. Geologica Macedonica, Vol 25, No 1, pp 67-72.
Non-metallic minerals
  • R B Ladoo
Ladoo, R.B. (1951), Non-metallic minerals, McGraw-Hill Book Company, Inc, New York, Toronto, London.
Examining the possible use of natural raw material "trepel"-Bitola for the synthesis of zeolite type 4A. XXII Congress of SCTM, Book of Abstracts
  • B Cekova
Cekova, B. et all (2012), Examining the possible use of natural raw material "trepel"-Bitola for the synthesis of zeolite type 4A. XXII Congress of SCTM, Book of Abstracts, Ohrid 5-9 September 2012, Republic ofMacedonia.
Low temperature synthesis of 4A from natural raw materials "pemza
  • B Cekova
Cekova, B. et all (2012). Low temperature synthesis of 4A from natural raw materials "pemza", XXII Congress of SCTM, Book of Abstracts, Ohrid 5-9 September 2012, Republic of Macedonia.