CC BY
12
DOI: http://dx.doi.org/10.20534/AJT-16-9.10-61-64
Kabulova Lola Baltamuratovna, Tashkent chemical-technological institute, Senior staff scientist, Department of Technology of inorganic substancestment Atakuziev Temirjan Azim ugli, Tashkent chemical-technological institute, Doctor of technical sciences, professor, Department of Technology of inorganic substances E-mail: ais-qr@mail.ru
Pilot batch of the mixed cements with the additive of composition of tuffite and SWSM
Abstract: In this work the technology of obtaining mixed portland cement with use as an active mineral additives of tuffite in the Karmana deposit and solid waste of soda manufacture (SWSM) has been investigated. The received data shows that tuffite breed burnt at 600 °C positively influences on the physical-mechanical properties of cements. The best results have been received at test of various cements at input of 20% and 30% of burnt tuffite additive.
Mixed portland cement containing simultaneously tuffites and SWSM are characterised concerning high grindability and less-water consumption than cements without additives.
Keywords: tuffite, solid waste of soda manufacture, portland cement, an active mineral additive.
Possibility of obtaining mixed Portland cements of 15% tuffite in 15 minutes the grinding residue on the rather high quality has been tested in laboratory with use as an active mineral additive of Karmaninsk deposit tuffite. Definition ofband indicators of cements with additives has been carried out on standard sample-beam structure 1:3, made of a solution of a plastic consistence.
It is known that portland-pozzolana cements differ with their heavy-water consumption. The same it is possible to tell and about the mixed cements containing 20-50% of tuffite in the structure: with the increase of tuffite maintenance their water consumption increases too, the increase of spread of tuffite cone is testified in figure 6. This factor negatively reflects and on strength characteristics of a cement stone: the additive of tuffite to 20% reduces the durability of initial Portland cement on compression order on 4-10%, but durability increases by a bend a little. Considerable decrease of stone strength indicators on the basis of tuffite containing portland cements is noted at 30%-s' dose of tuffite (on 20-45%), especially it is appreciable by 28 days (tab. 1).
Hence, earlier drawn conclusions that with a view of maintenance of enough high durability of a stone on the basis of tuffitecontaining cements, the maintenance of tuffite in them should not exceed 15%, since specified additive in the big doses sharply reduces durability of cement. It is established that at the presence of tuffite grind-ability of clinker considerably raises: in the presence of
sieve № 02 makes 20% that it is less on 5%, than in freeadditive cement (fig. 1). The increase in time of grinding to 30 minutes reduces quantities of the residue on the sieve to 12,0% that it is less on 3%. 1,5 hours duration of grinding promotes to obtain cement with a subtlety of crushing of the residue of 4% on the sieve whereas this quantity for free-additive cement makes 8%.
At replacement of 15% tuffite with equal quantity of SWSM grindability deterioration of mixes is observed, however, it is much better, than free-additive clinker mixes (fig. 2). Mixed portland cement containing simultaneously tuffites and SWSM are characterised concerning high grindability grindability and lower water consumption than cements with tuffite: the size of normal density of the cement paste has considerably decreased, it is obvious on the account of increase in the maintenance of small fractions at input of SWSM.
Portland cements with tuffite at combined grinding with carbonate waste containing small amount of CaCl2 are enriched with small fractions that leads to increase of activity of cements on the account of their optimisation of granulation, especially it is appreciable at a separate grinding ofportland cement clinker, and SWSM with their subsequent mixing; at these hardening of cement as it is specified above, it is accelerated in initial stages of hydration.
Intensity of carbonate interaction with hydration in particular on crystal structure of calcium carbonate of products of portland cement clinker and a hydraulic ad- and presence of impurity substances.
ditive — unequal tuffite, also depends on set of factors,
Fig. 1. The influence of quantity of tuffite on the cone spread
0 15 30 45 60 75 90
time of grinding nun.
Fig. 2. The influence of a kind of an additive on grindability of clinkers 1 - clinker of Navoiy cement plant (NCP) +5% of gypsum; 2 - clinker of NCP + 5% of gypsum +15% SWSM; 3 - clinker of NCP +5% of gypsum + 15% of tuffite; 4 - clinker of NCP + 5% of gypsum +13% of tuffite + 15% SWSM.
Table 1. - The influence of natural tuffite additives on the physical-mechanical properties of Navoiy portlandcement
№ п/п Composition of cement,% Normal denc-ity,% Limit of strength at a bend/compression, МPа
clinker gypsum tuffite day 1 day 3 day 7 day 28 day 90 Heat moist curing
1 2 3 4 5 6 7 8 9 10 11
1 95 5 - 24,0 3,8/30 4,3/33 4,6/41 7,2/54 8,0/58 5,4/38
2 85 5 10 29,7 3,4/20 3,7/28 4,4/39 7,2/49 7,1/52 4,5/34
3 75 5 20 34,4 3,3/19 3,3/22 4,0/31 5,2/34 5,7/36 4,0/33
4 65 5 30 34,4 3,2/18 3,3/20 3,8/27 4,5/31 5,2/22 3,7/29
1 2 3 4 5 6 7 8 9 10 11
5 60 5 35 35,9 2,9/16 2,9/20 3,5/24 3,9/26 4,3/29 3,5/25
6 55 5 40 40,1 2,9/15 2,9/18 3,3/23 3,7/25 3,5/26 3,3/22
7 50 5 45 46,1 2,6/14 3,2/14 3,2/19 3,4/22 3,7/23 2,6/18
8 45 5 50 47,0 2,2/13 2,7/13 3,1/16 3,3/19 3,3/19 2,3/15
The note: numerator — durability on a bend; a denominator — durability on compression.
Table 2. - The influence of natural tuffite additives on the physical-mechanical properties of cements
№ п/п Composition of cement,% Normal denc-ity,% Cementation time, hour-minute Limit of strength at a bend/compression, МPа
clinker tuffite start finish day 1 day 28 day 90 day 180 day 360
Bekobod portland cement
1 100 - 25,0 2-05 4-15 3,4/19 5,8/45 6,3/45 6,5/49 7,1/54
2 90 10 28,5 2-20 4-10 3,3/20 6,3/45 6,7/47 7,3/52 7,2/54
3 80 20 32,4 2-25 4-40 3,1/19 5,4/35 5,7/44 6,5/48 5,8/49
4 70 30 36,5 2-35 4-35 2,6/16 4,6/32 5,5/38 5,6/40 7,5/61
Ohangaron Portland cement
1 100 - 24,0 3-10 5-15 3,4/20 6,0/46 6,9/49 7,0/52 6,8/56
2 90 10 32,0 2-50 5-35 3,2/20 4,9/46 6,0/48 6,2/51 6,0/52
3 80 20 35,5 2-40 5-55 2,5/18 4,4/40 5,7/43 5,8/43 5,7/39
4 70 30 38,5 3-05 6-10 2,1/16 3,9/30 4,5/34 4,6/36 4,9/38
Table 3. - The influence of tuffite additives, burnt at 600 °C on physical-mechanical properties of Navoiy portland cement
№ п/п Composition of ce-ment,% - fl « Limit of strength at a bend/compression, MPa
clinker  S E s gs tuffite Sk sfî 1 day 1 day 3 day 7 day 28 day 90 HMC
1 95 5 - 24 4,0/31 4,5/34 4,8/42 7,5/56 8,4/61 5,6/44
2 85 5 10 26 4,4/25 4,6/34 4,8/46 7,8/56 7,8/57 5,5/40
3 75 5 20 28 4,5/29 4,8/41 5,4/44 5,4/48 6,1/53 4,4/45
4 65 5 30 30 4,5/42 4,6/44 4,9/46 5,5/57 5,6/63 4,6/53
5 60 5 35 33 4,1/34 4,5/36 4,8/42 7,5/53 7,5/57 5,5/45
6 55 5 40 35 3,4/22 4,0/31 4,6/42 5,7/46 7,0/48 4,7/38
7 50 5 45 36 3,3/21 3,6/23 4,0/31 4,7/32 5,2/34 3,8/32
8 45 5 50 37 2,8/16 3,3/17 3,3/21 3,6/23 3,9/25 2,8/21
Table 4. - The influence of tuffite additives, burnt at 600 °C on physical-mechanical properties of cements
№ n/n Composition of ce-ment,% Normal denc-ity,% Cementation time, hour-minute Limit of strength at a bend/compression, MPa
clinker tuffite ft s E s gs start finish day 1 day 28 day 90 day 180 day 360
1 2 3 4 5 6 7 8 9 10 11 12
Bel kobod portland cement
1 100 - 5 24,1 2-05 4-10 3,4/20 5,8/45 6,5/45 6,5/40 7,1/56
2 90 10 5 25,3 2-20 4-00 4,0/30 5,6/48 7,0/61 7,6/68 7,6/57
1 2 3 4 5 6 7 8 9 10 11 12
3 80 20 5 26,4 2-25 4-20 4,1/31 6,0/51 6,2/64 6,9/67 7,1/69
4 70 30 5 27,5 2-35 4-30 4,4/34 6,3/60 6,9/68 7,0/67 7,8/67
Ohangaron portland cement
1 100 - 5 24,0 3-10 3-15 3,4/21 6,0/48 6,9/49 7,0/50 6,8/56
2 90 10 5 26,0 2-40 5-20 3,6/32 6,3/56 6,4/57 6,5/58 6,3/61
3 80 20 5 27,0 2-39 5-50 3,8/34 5,7/60 6,0/61 6,1/63 6,1/64
4 70 30 5 28,0 3-05 4-10 4,0/40 6,4/65 7,0/67 7,1/68 7,4/69
The best results have been received at test of the various cements being made with burnt tuffite additive in the republic. Thus the adverse effect of montmorillonite impurity is eliminated, the water consumption of cement decreases, its strength indicator raises.
Under the active maintenance SiO2 and Al2O3 burnt tests differ from breeds in natural state a little. Activity on absorption of lime from solutions for the burnt tests has increased, their swelling capacity has raised.
The recieved data shows that tuffite breed burnt at 600 °C influences physical-mechanical properties of cements positively. Cements is characterised by intensive increase of durability by 28 days, its hardening and steady growth in longer terms.
The best results are received at input of 20% and 30% of an additive. It has been shown as earlier by us that tuffites burnt at 600 °C make positive impact on grindability of clinker.
Clinker, gypsum, tuffite, SWSM are delivered supply bunker (fig. 3) by means of belt conveyors, whence they
arrive on disk feeders where are dosed out in a certain parity. Dosed components blends arrive in a funnel of the cement mill.
Cement mill in the size 4,0x13,5mm, two-chamber where the first chamber is filled with spheres (balls), and the second with tsilpebs. The mill works in an open cycle with number of turns of 16,2 pour a minute. Movement is run by means of the central drive consisting of the electric motor, a reducer; half couplings and the central shaft.
The arrived components are exposed to a high milling, by means of grinding bodies, to grinding [milling] fineness with the residue on a sieve № 008 to 12-15%. The fine powder is portland cement with the composite additives, obtained on the bases of clinker, gypsum, tuffite and SWSM.
The obtained mixed cement by means of the pneu-mochamber pump on cement wires is transported in the cement silo, for storage and shipment to consumers. The obtained cement is shipped in wagon in railway cars or in cement truck.
Fig. 3. Process flowsheet of manufacture
