Improving the efficiency of chrysotile-cement products is achieved by changing the raw materials with additives, changing their structure and properties, generating new kinds of chrysotile-cement productsnoBelgorod State Universit

Naumova, L. N.

Vezentsev, A. I.

DSpace at Belgorod State University

Increasing the production efficiency of chrysotile cementproductsVezentsev A .I.1. N aum ova L.N .21- B elgorod  S ta te university, Belgorod, Russia2-B elgorod  State Technological University, Belgorod, Russiae-mail: bezentseg@ bsu.edu.ruAbstractIn modem conditions special meaning gets the further increase o f efficiency chrysotile cement products, in particular, roofing chrysotile cement sheets, perfection o f  technology o f their manufacture, increasing in labour productivity and improvement o f  their ecological safety. It is achieved due to modifying raw components (cement, chrysotile) by means o f additives, changing o f their structure and properties, reception o f new kinds chrysotile cement products.One o f the major operations in manufacture chrysotile cement products, determining productivity o f technological lines and quality o f final products is chrysotile crusing [1].Process chrysotile crushing includes infringement o f modular coherence i between elementary fibrils in a bunch, division o f bunches into thinner fibres on planes with broken sealing, breaks and milling o f fibres, formation o f secondary structure due to coagulation o f finely dispersed particles [2].Various chemical additives promoting acceleration o f crushing, to increase of adhesion o f particles o f  cement with fibres chrysotile in chrysotile cement jj! weight, the reduction o f  duration o f processing, reception o f a thin fibre 1 chrysotile are known. Thin fibres o f chrysotile, in regular intervals distributed |  in a cement matrix, form the reinforcing grid essentially increasing its durability |  at stretching, and impact strength. Mechanical properties o f chrysotile cement are determined by many factors: the contents o f chrysotile and its quality (average length o f fibres and their diameter), uniformity o f distribution o f fibres in cement, its chemical and mineralogical structure and a fineness o f a milling, density o f chrysotile cement stone, conditions o f hardening, etc.The durability o f chrysotile cement products depends on their density. Frost resistance o f  such products makes: in density o f cycles 1,57 g/sm3-25; in density : 1,65 g/sm3- 50 cycles; in density 1,80 g/sm3- 100 cycles o f freezing and thawing l[3]. Now to produce disperse chrysotile we apply gringing mills, counterflow  jamalgamators, hom ogenisators, paper-m aking desintergrators, drum-type Jrefiners, spherical m ills , ham m er m ills o f  a w et grinding, u ltrasound equipment and microsprays.With the purpose o f an intensification o f the process chrysotile crushing jand improvement o f quality o f  chrysotile cement products we use the additive sodium liquid glass. Introduction o f the additive in amount 0,l-0,5m l/10g of jjchrysotile carried out at a stage o f chrysotile crushing o f marks -5-65 - 100 % and chrysotile charge o f structure A-4-30 (15weights %), -5-65 (55 weights. %), A-6-45 - (30 weights. %) deposits o f Bazenov. Properties o f chrysotile andchrysotile charge are presented in table 1. Introduction o f liquid glass promotes increase in a degree o f chrysotile crushing and chrysotile charge on 18-22 % that is important for reception o f products with demanded properties.Table 1The degree o f chrysotile crushingThe nam e o f  o b je c t research Humidity, w eights.% The D e g re e o f crushing chrysotileChrysotile contro l 6 4 ,8 -6 7 ,6 7 5 ,8 -7 6 ,3M odified chrysotile 6 6 ,4 -7 0 ,6 9 4 ,7 -9 8 ,0C hrysotile con tro l charge 6 3 ,5 -6 8 ,0 7 3 .4 -7 6 ,6C hrysotile charge, modified 6 8 ,0 -7 0 ,2 9 1 ,0 -9 5 ,0Technological tests o f chrysotile cement suspension and chrysotile cement on m odified chrysotile (table.2) have shown, that ablation o f cement at a filtration o f chrysotile cement suspension in baths o f mesh cylinders has decreased on 0,6036 g/1, that explains by increasing o f a chrysotile crushing degree, so, by a greater surface o f  coupling o f fibres chrysotile w ith cement particles that promotes increasing in density chrysotile cement on 200 kg/m3, to reduction, accordingly, water absorptions on 0,6 weigts. % and porosity on 5,2vol. %.Table 2Technological properties o f chrysotile cement suspension and operational characteristics o f chrysotile cementW ay o f introduction The Index of Ablation, Density W ater absorption, Porosity,o f the additive the sample g/1 kg/m3 weights.% vol.%The Method o f moist pressingK, _ 1940 19,4 41,6At chrysotile 3 , - 2170 19,0 36,9 -crushing in a The Method o f  a filtrationnydroiluiierK2 0,9615 1600 18,6 34,23 , 0,3579 1800 18,0 29,0At hardening into 3 3 - 1570 13,8 21,7solution o f liquid 34 - 1670 12,4 20,7glass in dampener 3 5 - 1740 10,5 18,3The basic properties o f chrysotile cement products were studied on the samples made on rysotile, modified by liquid glass (an index o f samples -3,, 3 , ,  table 2). Also they studied properties o f the samples hardening in a solution o f  liquid glass w ith various concentration: 0,5; 1,0 and 1,5 weights. % from total amount o f  water ( 3 3, 3  4, 3  5 table.3).It is experimentally shown, that at introduction o f the additive o f liquid glass, the durability o f chrysotile cement samples tested in 7 - daily age, has increased in comparison with chrysotile cement samples on commodity chrysotile on the average in 1.3 times. Increase o f durability at a bend o f chrysotile cement samples on modified chrysotile is explained by the best adhesive properties o f the fluffed up fibres o f  chrysotile, promoting to strons coupling with a cement stone.Table 3The limit o f the strength at a bend o f chrysotile cementW ay o f  in troduction o f  the additive Strength at a bend, MTIA O bject o f  researchL im it o f  durability at a bend, M PAA t chrysotile  crushing in the hydroflufferThe M ethod o f  m oist pressingC om m odity (Ki) M odified (3 i)13,018,5The M ethod o f  a filtrationCom m odity (IG) M odified ( 3 2)10,412,1A t w ater-saturation in a dam penerM odified ( 3 3) M odified (34) M odified ( 3 5)13,015.716.8The analysis o f results o f the tests on heat distortion temperature and cold endurance has allowed to determine that loss o f durability at a bend for chrysotile cement samples, made on commodity and modified chrysotile has formed, |  accordingly, 9,6 and 7,6 % and 7,4 and 5 , 7 % .  Thus, loss o f durability has not I exceeded 10 % that corresponds to requirements o f physicomechanical tests.During definition o f weather resistance, it observed not the decrease o f I  durability chrysotile cement products, but, on the contrary, its increase, which ;has made 32.6 and 33.8 %, accordingly, for chrysotile cement products on |com m odity  and m odified chrysotile. Thus, crack form ation and v isib le stratification were not observed. The growth o f durability is explained by that, during 28 day o f hardening the degree o f hydration o f cement increases. The increase o f durability chrysotile cement products is connected not only with increase in a specific surface fluffed up chrysotile asbestos, but also with a qualitative change o f structure o f its surface due to chemisorption o f silicon- oxygen anions and cations o f calcium, and also due to the diffusional processes, proceeding in the interfibrillar space o f fibres bunches.On the basis o f the received results on intensification crysotile crushing jdue to introduction o f the additive sodium liquid glass the technological scheme •of manufacture o f roofing chrysotile cement sheets (fig. 1) is modernized. For ^industrial realization o f the given development it is necessary in addition to ^determine the capacity for storage o f liquid glass and the batchbox.1Conclusions:|  1. It is shown, that modifying chrysotile sodium liquid glass promotes increase|J  o f a degree o f crushing on 18-22 %, leads to reduction o f ablation o f cement/-i at a filtration o f chrysotile cement suspension in baths o f mesh cylinderson 0,6036 g/1, to increase in density chrysotile cement on 200 kg/m3.«  2.It is revealed, that the mechanism o f modifying chrysotile consists in interaction o f liquid glass  with fibres and allocation o f hydrogel silica, _ that promotes improvement o f operational characteristics o f chrysotilecement products. The strength o f chrysotile cement products at a bend increases for 16 %.F ig.l The Modernized technological scheme o f manufacture o f roofing chrysotile cement sheetsReferences:1. Shlapakov U. A. The Research o f  asbestos  crushing in factory units. In b. Technology of form ation o f  asbestos cement products, Kalinin, 1982, p. 9-19.2. Berney 1.1. The Technology o f asbestos cem ent products - The H igher school, - 1977. p. 230.3. P opov .N., K addo M .B., ulkov O.V. Q uality estim ation o f  building materials, M: Publishing house Assots. Builds. H igh schools, 1999, p. 60.

Increasing the production efficiency of chrysotile cement products

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Increasing the production efficiency of chrysotile cement products

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