Properties


Perlite research

The results of studies carried out by leading specialized research institutes of Ukraine and the United States have confirmed that the properties of expanded perlite sand obtained from raw materials from the Fogosh deposit of Ukraine meet the highest standards.

Its use is recommended in various industries: in construction, agriculture. cryogenic engineering, metallurgy, for the production of filtering perlite powder used for the filtration of sugar syrups, beer, wine, vegetable oil, petroleum products and medicines.

Study of indicators of expanded perlite sand produced from perlite raw materials from deposits of Ukraine (Fogosh), Greece (Milos island), Armenia (Aragatskoe), Turkey (Bilesik), Georgia (Paravanskoe).

Expanded perlite sand obtained by heat treatment of natural perlite raw materials of volcanic origin is widely used in the construction industry and in other industries.

Industrial use of expanded perlite sand is predetermined by its operational characteristics, the main of which are bulk density, fraction, thermal conductivity, strength, water absorption, degree of compaction. Obtaining expanded perlite with the required quality parameters depends on the properties of the used pearlite raw materials and the peculiarities of the technology of its heat treatment.

All existing varieties of perlite are divided into two large groups: primary hydrated rock and secondary hydrated rock or primary perlite and secondary perlite, which have different properties. The main characteristic of perlite is the content of structural water, which is the main agent of rock swelling. The amount of structural water in primary perlite is 1.5 to 4.5%. The amount of structural water in secondary perlites is 4.5 to 9.5%.

This work is devoted to the study of indicators of expanded perlite sand produced from perlite raw materials currently used at perlite enterprises in Ukraine and Europe – perlite raw materials from deposits in Greece, Turkey, Armenia, Georgia, related to primary perlite, and Ukrainian deposits, related to secondary perlite.

Tables 1 and 2 show the chemical composition and physical and technical characteristics of pearlite samples from the above deposits.

Table 1 Chemical composition of perlite raw ore

Quarry Chemical composition, %
SiO2 Al2O3 Fe2O3 TiO2 CaO MgO SO3 Na2O K2O Н2O
Fogosh (Ukraine) 72,20 12,30 2,23 0,10 0,88 0,10 0,03 1,84 5,06 5,2-5,5
Greece (Milos island) 75,24 12,47 1,49 0,14 1,59 0,40 0,03 3,20 2,20 2,50
Bilesik (Turkey) 73,2 12,45 0,92 0,09 0,55 0,26 3,35 3,90 3,26
Aragats (Armenia) 74,15 11,90 0,71 0,10 1,72 0,13 0,27 4,02 4,40 3,52
Paravan (Georgia) 73,28 12,93 0,92 0,13 0,68 0,23 0,00 4,18 3,00 3,66
Table 2 Physical and technical characteristics of perlite raw ore

Field name Quarry True density (without pores), g / cm3 Average density (including pores), g / cm3 Porosity of granules,% Compressive strength, MPa
1 Fogosh (Ukraine) 2,38 1,56 34,6 20,0
2,37 1,75 26,2
2 Greece (Milos island) 2,37 1,70 28,3 17,0
3 Bilesik (Turkey) 2,37 1,67 29,5 18,0
4 Aragats (Armenia) 2,35 1,82 22,6 16,0
5 Paravan (Georgia) 2, 36 1,59 32,6 8,4

To determine the quality indicators of expanded perlite sand obtained from the raw materials of the deposits of Ukraine, Greece, Turkey, Georgia, Armenia, samples of expanded perlite sand were dispersed into fractions of 0.63-1.125 mm; 1.25-2.5mm; 2.5-5.0 mm, and quality indicators were determined for each narrow fraction of expanded perlite produced from pearlite from different deposits. The following main quality indicators were determined: bulk density, thermal conductivity, compaction coefficient, compressive strength in the cylinder, water absorption by weight and volume, thermal conductivity. The test methods correspond to the test methods in force in Ukraine and the CIS countries,and take into account the peculiarities of the methods of the World Perlite Institute. The results of the determinations are presented in Table 3 and in graphs 1-4 (the full original study with graphs is available in the attached PDF-file).

Original study.pdf

Table 3 Indicators of the quality of expanded perlite sand obtained from raw ore from various quarries

Наименование пробы Fraction, mm Bulk density, kg / m 3 Thermal conductivity W / m*C

Compaction ratio

Water absorption ,% Compression strength in the cylinder, MPa
по массе по объему
1 2 3 4 5 6 8 9 10
1. Quarry Fogosh of Ukraine (γ = 263 kg / m 3) 2,5-5,0 182,0 0,049 1,085 96 17,5 0,42
1,25-2,5 278,4 0,078 1,060 120 33,4 0,58
0,63-1,25 232,0 0,078 1,107 130 30,7 0,38
2. Quarry Fogosh of Ukraine (γ = 127 kg / m 3) 2,5-5,0 158,8 0,046 1,093- 150 23,8 0,36
1,25-2,5 114,8 0,044 1,118 330 37,9 0,21
0,63-1,25 104,0 0,048 1,153 425 44,2 0,15
3 Quarry Fogosh of Ukraine (γ = 89, 6kg / m 3) 2,5-5,0 71,2 0,042 1,135 240 171 0,175
1,25-2,5 77,6 0,040 1,137 425 33,0 0,15
0,63-1,25 83,0 0,043 1,175 490 40,7 0,12
4 Quarry Fogosh of Ukraine (γ = 72 kg / m 3) 1,25-2,5 67,2 0,038 1,145 450 30,2 0,13
0,63-1,25 71,2 0,042 1,21 530 37,7 0,11
5. Quarry of Greece (Milos Island) (γ = 82.2 kg / m 3 ) 2,5-5,0 90,0 0,040 1,16 250 22,5 0,13
1,25-2,5 75,0 0,040 1,17 455 34,1 0,10
0,63-1,25 65,0 0,039 1,27 580 37,7 0,08
6. Quarry of Bilesik Turkey (γ = 85.3 kg / m 3 ) 2,5-5,0 93,2 0,040 1,13 250 23,3 0,125
1,25-2,5 86,0 0,041 1,15 450 38,7 0,11
0,63-1,25 72,2 0,042 1,22 610 44,0 0,095
7 Quarry Aragats of Armenia (γ = 83kg / m 3 ) 2,5-5,0 99,7 0,040 1,13 230 22,9 0,16
1,25-2,5 87,2 0,040 1,15 455 39,7 0,11
0,63-1,25 59,2 0,039 1,21 690 40,8 0,07
8. Quarry  Paravan Georgia (γ = 47 kg / m 3 ) 1,25-2,5 38,7 0,031 1,23 1051,7 40,7 0,036
0,63-1,25 46,2 0,038 1,22 1061,6 49,0 0,032

γ – bulk density (kg / m 3 )

Table 4 Comparative analysis of the main characteristics of expanded perlite sand produced from perlite raw materials from various deposits (for a fraction of 0.63-1.25 mm and a bulk density of 82-89 kg / m 3)

Compaction factor
Perlite quarries in Greece, Turkey, Armenia, Georgia

1,21-1,27

Perlite quarry Fogosh of Ukraine

1,175

Cylinder Compressive Strength
Perlite quarries in Greece, Turkey, Armenia, Georgia 0,07-0,08 МPа
Perlite quarry Fogosh of Ukraine 0,12 МPа
Water absorption by weight
Perlite quarries in Greece, Turkey, Armenia, Georgia

580-690 %

Perlite quarry Fogosh of Ukraine

490 %

Thermal conductivity
Perlite quarries in Greece, Turkey, Armenia, Georgia 0,039-0,042 W/m*C
Perlite quarry Fogosh of Ukraine 0,043 W/m*C

Findings

At perlite enterprises in Ukraine, for the heat treatment of perlite from the Fogosh quarry, an improved two-stage technology of “NIISMI” is used, including preliminary thermal preparation of raw materials in a special fluidized bed thermal preparation furnace and then swelling in a shaft furnace. This technology, due to the regulation of the amount of structural water in the perlite rock within the required limits, makes it possible to produce expanded perlite sand with the required porous structure and, as a consequence, with the required performance characteristics.

Under industrial conditions, granulated expanded perlite sand with a wide range of properties can be produced from the raw materials of the Fogos quarry:both light expanded perlite sand with a bulk density of less than 100 kg / m3mid=65-90 kg/м3) with a developed fine-porous structure, and heavy (γmid = 100-220 кг/м3) expanded perlite sand with a predominantly closed porous structure.

The quality indicators of expanded perlite obtained from the tests, produced from perlite raw materials from the Fogosh deposit (Ukraine), compared with the quality indicators of expanded perlite produced from raw materials from the deposits of Greece, Turkey, Armenia, Georgia, with a comparable average bulk density and fraction, are characterized by 50% greater strength of expanded granules and 20-30% lower water absorption , which accordingly reduces the degree of its compaction.

These advantages of perlite from the Fogosh deposit (Ukraine) are of particular importance in construction, where the main requirements are increased strength characteristics, reduced water absorption and minimal compaction, which predetermines the stability of thermal characteristics.