stanje i perspektive u rudarstvu i odrţivi razvoj mining present state ...

Rudarstvo 2011 / Mining 2011Table 9. Pellets impact resistance after 7 days of airing.Number of droppings 1 5 10 15 20 251 % cement 1,40 3,70 9,40 15,80 22,90 29,80SM, % 3 % cement 0,80 3,10 5,10 6,90 8,60 10,10-2mm 5 % cement 0,60 2,70 4,70 6,10 7,60 9,207 % cement ----- 0,40 0,90 1,25 1,65 2,10Table 10. Pellets impact resistance after 28 days of airing.Number of droppings 1 5 10 15 20 251 % cement 0,40 2,20 7,80 15,40 22,90 28,80SM, % 3 % cement 0,30 1,25 2,40 3,40 4,15 4,75-2mm 5 % cement 0,20 0,90 1,50 2,00 2,40 2,857 % cement 0,10 0,40 0,60 0,80 0,90 1,20Generally speaking, the impact resistance rise with the increase in binding agent content, as well astime of airing.5.0. TESTING PHYSICAL AND MECHANICAL PROPERTIES OF CEMENTAfter conducting the tests of the pellet mechanical properties, as mentioned above, the sample with5% of adhesive (based on mechanical properties and binding agent mass content) was chosen forproduction of cement that was tested for mechanical and physical properties. Two samples of cementmixture were made. The first sample (I) was made in standard way from ash and gypsum in powderedstate with klinker, while the second one (II) was made from pellets of ash and gypsum with 5% ofcement and klinker.The test results of the physical and mechanical properties are shown in Table 11.Table 11. Physical and mechanical properties of cement samples (I and II).Physico-mechanical propertiesFineness of milling oversize on sieve 0,09 mm, %specific area (Blaine), cm 2 /gcement I 1,50cement II 2,60cement I 5000cement II 4670Volumetric mass, g/cm 3 cement I 3,06cement II 2,99Water for standard consistency, % cement I 28,00cement II 28,00Binding time h,minSteadiness ofvolumestartfinishcement I 04:45cement II 05:00cement I 05:45cement II 06:00cakescement I Steadycement II Steadyle Chateliercement I 0,0cement II 0,5Mechanical properties674