It is shown that using silica sand of Tugansk deposit (Tomsk region) and marshalite of Elbash deposit (Novosibirsk region) having more developed specific surface in comparison with silica sand of Tashlin deposit (Ulyanovsk region) in combination with their grain defective structure provides an increase of batch chemical activity at the stage of silica- and glass-formation. The effective method of preparing glass batch using substandard fine-dispersed siliceous materials in glass production is their compaction

Frolova, I. V.

Kazmina, О. V.

Krasheninnikova, N. S.

Electronic archive of Tomsk Polytechnic University

Glass production refers to material and energy intensive technologies, where natural and manmade rawmaterials are widely used. The main constituent of themajority of industrial batches is natural siliceous materials (silica sand, quartzite, sandstone, vein silica) andsynthetic alkali containing materials (soda ash, sodiumsulphate, sodapotash mixture).Recently enterprises of glass industry frequently face the problem of raw materials deficit stipulated by reserve depletion of imported conditional materials, by distance of raw materials bases from consumers, by lack ofattention to the questions connected with modernization of operative deposits and mining of new ones.One of the methods of solving this problem is usingof new – nondeficient and mediumpriced raw materials of natural and anthropogenic origin, which allow insome cases not only to decrease production price but tointensify a process of glass manufacturing [1].In the given paper the influence of replacement ofTashlin deposit silica sand widely used in various types ofglass manufacturing by substandard natural siliceous materials on process of pulping and glass quality was investigated. The subjects of inquiry are silica containing consistentof Tugansk deposite (Tomsk region) obtained while zirconilmenite ore concentrating and concentrated marshalite ofElbashin deposite (Novosibirsk region). The possibility inprinciple of using these materials in container glass manufacturing was determined by the authors earlier [2, 3].Studying of influence of siliceous materials natureon the process of pulping was carried out on modelingbatches representing three component mixture of sand,soda and dolomite in ratio 60:20:20 wt. % (respectively).Three sets of experiment were carried out, where as a siliceous component of a batch Tashlin sand, Tugansksand and marshalite were used. Chemical compositionof investigated raw materials is presented in table 1.Table 1. Chemical composition of siliceous materialsGlass manufacturing is a difficult physicalchemicalprocess occurring at high temperatures in moving medium of variable composition, which depends on batchcomposition, conditions of heat exchange, temperatureetc. By convention the process of glass manufacturing isdivided into separate stages: silicate formation, glassformation, fining, homogenization, cooling. Every microvolume of a batch undergoes these stages in the process of its transformation into glass mass.Different processes of physical and chemical naturesuch as components fusion, polymorphic transformations, solidphase reactions, silicates formation etc. occur at the stage of silicate formation. Rate of silicate formation is determined by temperature conditions,nature, dispersion and chemical activity of batch components including siliceous one.Solidphase reactions occurring at the stage of silicate formation are presented in general terms by the following equations:Na2Mg(CO3)2+2SiO2→Na2SiO3+MgSiO3+2CO2Na2Ca(CO3)2+2SiO2→Na2SiO3+CaSiO3+2CO22CaCO3+SiO2→Ca2SiO4+2CO2Na2CO3+SiO2→Na2SiO3+CO2Batches chemical activity was estimated accordingto the degree of their transformation, which is describedwith high accuracy by the value of mass loss, and interms of calculation of energy activation [4].The results of differentialthermal analysis obtainedat a derivatograph (Q1500 D PaulikPaulikErdey) in apolythermal regime (20...1000 °С), with heating rate10 °С/min, showed the presence of three groups of endoeffects. Endoeffects conneced with various forms ofmoisture removal are present in a lowtemperature region (to 150 °С). The second group of effects at temperatures 538, 540, 560 and 751 °С conforms to the processes of dissociation of magnesium carbonate,polymorphic transformations of silica and beginning ofsolidphase reactions with the formation of double saltsand various silicates. The third group of endoeffects conforming to the fusion of eutectic silicates series Са, Мgand Nа was observed for the batch with Tashlin sand attemperature 830 °С, for the batches with Tugansk sandand marshalite at temperature 815, 812 °С respectively.It is stated that at the stage of silicate formation, whenusing conventional sand, batch mass losses reach 9 %,while for batches with Tugansk sand and marshalite masslosses are 15 and 17 % respectively. Differences in masslosses are stipulated by finedispersed composition of Tugansk sand and marshalite (fig. 1), which 45 and 85 % (reRaw materialsChemical composition, wt.%SiO2 Al2O3 Fe2O3 СаО MgO TiO2 п.п.п.Tashlin sand 99,10 0,27 0,10 0,07 0,05 – 0,41Tugansk sand 98,15 0,67 0,09 0,07 0,02 0,06 0,94Marshalite 97,43 – 0,15 1,4 0,70 – 0,32Bulletin of the Томsк Pоlytеchnic University. 2007. V. 310. № 1120UDC 666.1.01:66.1.031:66.046.52BATCH PULPING ON THE BASIS OF NATURAL SUBSTANDARD SILICEOUS MATERIALSN.S. Krasheninnikova, О.V. Kazmina, I.V. FrolovaTomsk Polytechnic UniversityЕmail: kazmina@tpu.ruIt is shown that using silica sand of Tugansk deposit (Tomsk region) and marshalite of Elbash deposit (Novosibirsk region) having moredeveloped specific surface in comparison with silica sand of Tashlin deposit (Ulyanovsk region) in combination with their grain defective structure provides an increase of batch chemical activity at the stage of silica and glassformation. The effective method of preparing glass batch using substandard finedispersed siliceous materials in glass production is their compaction.spectively) consist of fractions that are less than 0,16 mm.Specific surface value of Tashlin sand is 1037 sm2/g for Tugansk sand and marshalite it is 2000 and 3000 sm2/g respectively. Moreover, increase of batch chemical activitywhen using finedispersed siliceous materials is stipulatedby structure imperfection of their grains (fig. 2).Fig. 1. Granulometric composition of sand: a) Tashlin, b) Tugansk, c) marshaliteActivation energy values were carried out by wellknownprocedure on which basis there is the Arrhenius equation.К= А.e–Eа/RT,where К is the reaction rate constant; А is the coefficient of proportionality; Еа is the activation energy; R isthe gas constant; Т is the absolute temperature.аbFig. 2. Electron microscope photographs: a) marshalite; b) Tugansk sandFig. 3. Changing of transformation degree when heating the batches on basis of sand: a) Tashlin; b) Tugansk; c) marshalite attemperature in °С: 1) 550; 2) 650; 3) 700; 4) 750; 5) 800 c b010203040506070800 1 2 3 4 5 6Transformation degree, %010203040506070800 1 2 3 4 5 6Transformation degree, %01020304050607080900 1 2 3 4 5 6Transformation degree, %234513452345121?05101520253035Fraction content, %0 0,1 0,16 0,2 0,25 0,315Particle size, mmb) 0102030405060Fraction content, %0 0,1 0,16 0,2 0,25 0,315 0,5 0,63Particle size, mm?)01020304050607080Fraction content, %   < 0,1   0,1  0,16    0,2c)Particle size, mmChemistry121Reaction rate constant was determined analyticallyfrom the HinstlingBrownstein equation which describes rather accurately kinetics of solidphase process inisothermal conditions.Fhb= 1–2/3G–(1–G)2/3=Кτ,where Fhb is the HinstlingBrownstein function; G is thepart of a substance entered into reaction; К is the reaction rate constant; τ is the reaction time.Activation energy was determined by the values of Kfor different temperatures:Curves of batches transformation degree when heating them in the rage 550...800 °С depending on processduration are presented on fig. 3. As it is seen, the batchon basis of silica sand of Tashlin deposit has the least degree of transformation (65...68 %) on the stage of silicate formation (fig. 3, a).Calculated values of activation energy amounted55,35 kJ/mole for a batch of Tashlin sand and 53,66 and45,23 kJ/mole for batches on basis of Tugansk sand andmarshalite respectively. Lower values of activation energy indicate increased rate of silicate formation reactionin batches on basis of substandard siliceous materials.Limiting stage of glass manufacturing is glass formation in the duration of which silica grains dissolution insilicate melt and simultaneous silicates dissolution occur. For sodium calcium silicate glass this stage isusually completed at temperature of the order of1200 °С when transparent glass mass is obtained. It isknown that dissolution time of silica grain τ is connected with its size by r dependence [5].τ=Вr3,where В is the coefficient depending on glass composition.Probably the high degree of Tugansk sand and marshalite dispersion promotes the increase in reaction rate ofglass formation. However the given materials do not conform to the requirements of State Standard (SS) 2255177for siliceous materials because of high (in 1, 5... 2 times) fines content (less than 0, 1 mm) that influences negativelythe process of glass degassing and glass quality. It is knownthat sealing allows improving technological property of disperse materials and glass batches, therefore further research was carried out at sealed batches. The batch on basisof Tugansk sand was sealed by the method of compressionat rolling press, the batch on marshalite was sealed by graining using the method of balling at plate granulator.Laboratory melting of sealed glass batches for container glass manufacturing with the use of substandard siliceous materials was carried out in corundum crucibleswith a capacity of 200 ml in a smallsized electric furnace with silite heaters and automatic control of temperature condition. Rate of temperature rising was 250 degrees/h.; maximal temperature was 1450±10 °С at15 minute exposure. Glass formation rate was estimatedaccording to the results of Xray analysis of glass samples(diffractometer DRON3М in copper radiation).Sampling of glass obtained from the batches at investigated siliceous materials was carried out in the temperature range of 900...1200 °С. The rate of glass formation was considered by changing intensity of reflectionmaximums conforming to silica (4,23; 3,34; 1,815 A).As we see from fig. 4 there is no significant difference inintensity of silica reflection maximums for the batcheswith Tugansk and Tashlin sand in the temperature range 900...1000 °С. Further temperature rising to 1200 °Сresults in quantitative decrease of silica. The values ofabsolute intensities of silica reflection maximums decrease approximately in 1,5 times in glass samples, boiledfrom the batch on basis of Tugansk sand.Fig. 4. Changes in intensity of silica reflection maximums inbatches on basis of sand: a) Tashlin; b) TuganskThe results of Xray analysis (fig. 5) of glass samplesfrom the batch on basis of marshalite selected at temperature 1200 °С showed that at simultaneous decrease inintensity reflection maximums conforming to silica theincrease of amorphous halo area is observed, i. e. batchchemical activity rising.Thus, the results of fulfilled laboratory melting showthe increase of glass formation reaction rate in the caseof substandard siliceous materials that is stipulated notonly by their finedispersion and grains structure peculiarities, but also by reacting components intimate contact which is achieved at sealing.? bAbsolute intensity of silica reflection maximums, mm  12 1 21 1lg .2,3aEKK R T T⎛ ⎞= ⋅ −⎜ ⎟⎝ ⎠Bulletin of the Томsк Pоlytеchnic University. 2007. V. 310. № 1122Fig. 5. Changes in intensity of silica reflection maximums forbatches on basis of: a) Tashlin sand; b) marshaliteStandard samples, visual examination of whichshowed the presence of complete fusion and glass clearing, were prepared from obtained glass mass. According to the results of determination of physicalchemical properties of glass (table 2) it is seen thatcharacteristics of the samples obtained from the batches on basis of substandard siliceous materials conform tothe requirements of branch standards, formed for tocontainer semiwhite glass. The analysis of transmissionspectra carried out with the use of spectrophotometerSPh26, for samples of 3 mm thick, in spectral region400...700 nm, showed that glasses at the researched siliceous materials have the value of optical transmissionon 1...3 % lower in comparison with the glass meltedfrom the conventional sand of Tashlin deposit, that isnot a matter of principle for container glass.Table 2. Glass samples propertiesTCLTE – thermal coefficient of linear thermal expansionThe results of carried out investigations showed thatsubstitution of conventional silica sand on Tugansk sandor marshalite in batches composition for container glassmanufacturing results in increase of reaction rate of silicate and glass formation, stipulated by high chemicalactivity of batches and allows production of qualitativeglass. The effective method of batches preparation usingnatural substandard finedispersed siliceous materials istheir sealing.Glass obtained onbasis ofTCLTE ×107,degree–1 inthe range20...400 °СDensity,g/sm3General optical transmission of the samplesof 3mm thick in region400...700 nm, %Tashlin sand 90,0 2,50 87Tugansk sand 91,0 2,52 85Marshalite 91,5 2,51 84The requirements ofState Standard (SS)92 2,48…2,52 6552545658510515 25 35 45 55???? 2 ???????????????????????????, %Relative intensity, % Angle?52545658510515 25 35 45 55???? 2???????????????????????????, %AnglebRelative intensity, % Chemistry123REFERENCES 1. Zaitseva M.I., Atkarskaya A.B. Unconventional raw materials and methods in glassmaking // Glass of the world. – 2005. – № 5. – P. 60–67.2. Krasheninnikova N.S., Kazmina O.V., Frolova I.V. Using of silicaconcentrate in flat glass technology // Bulletin of the Tomsk Polytechnic university. – 2004. – V. 307. – № 2. – P. 120–122.3. Krasheninnikova N.S., Kazmina O.V., Frolova I.V. Technologicalpeculiarities of marshalite using in container glass manufacturing //Glass and ceramics. – 2006. – № 2. – P. 11–13.4. Tretyakov Yu.D. Solidphase reactions. – Moscow: Chemistry, 1978.– 360 p.5. Krasheninnikova N.S., Frolova I.V., Kazmina O.V. Method of preparation of homogeneous glass batch // Glass and ceramics. – 2004.– № 6. – P. 3–4.Arrived on 11.12.2006

Batch pulping on the basis of natural substandard siliceous materials

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