COLEGIUL EDITORIALBDITORIAL BOARD

P reg ed i nte/President:Prof. ION TEOREANU

Universitatea POLITEHNICA Bucuregti - RomAnia

Secretar/SecretaryDr. VASILICA DIMA

PROCEMA S.A. Bucuregti- RomAnia

Membri/ Members

Prof. ECATERINA AN DRONESCUUniversitatea POLITEHNICA Bucuregti - RomAniaProf. PETRU BALTAUniversitatea POLITEHNIeA Bucuregti - RomAniaProf. NORMANDO PERAZZO BARBOSACentre of Technology, Federal University ofParaiba, BrasilDr. FRANCIS CAMBIERCentre de Recherches de L' industr ie Belge de laC6ramique, Mons - BelgiumPrOf. LILIANA CRACIUNESCUUniversitatea Tehnicd de Construclii Bucuregti -RomAniaDr. CRISTINA DUMITRESCUCEPROCIM S.A. Bucuregt i - RomAniaProf. MIHAI ENACHEUniversitatea Tehnicd Timigoara - RomAniaDT. CHARLES FENTIMANCement Concrete Research Centre, Horsam, UKProf. MARIA GEORGESCUUniversitatea POLITEHNICA Bucuregti - RomAniaDr. TRAIAN ISPASPROCEMA S.A. Bucuregti - RomAniaProf. IOAN LAZAUUniversitatea Tehnicd Timigoara - RomAniaProf. LIVIU LITERATUniversitatea Babeg-Bolyai, Cluj Napoca-RomAniaProf. MARCELA MUNTEANUniversitatea POLITEHNICA Bucuregti - RomAniaProf. IOANNA PAPAYIANNIAristotle University ThessalonikiDepartment of Civi l EngineeringLaboratory of Building Materials - GreeceProf. MARIA PREDAUniversitatea POLITEHNICA Bucuregti - RomAniaDr. DORU PU$CA$UCEPROCIM S.A. Bucuregti- RomAniaDr. EMIL ROTIUInsti tutul Nalional de Sticld ( lNS) Bucuregti-RomAniaDr. NELU SPIRATOSHandy Chemicals Company - CanadaDr. MARIA ZAHARESCU, membru corespondental Academiei RomAne, Institutul de Chimie - Fizicit

" l .G. Murgulescu " alAcademiei RomAneDr. VLADIMIR ZIVICAInstitute of Constructions and Architecture, SlowakAcademy of Sciences - Slowakia

Coordonator:

Ing. ION BERCA

Redactor:lng. VIRGINIA MOLDOVEANUTeh noredactare computerizatd :Ing. ANDREIA DANILAEste interzisi conform legii, reproducerea integral5sau parfiall a confinutului revistei, pe orice cale giprin orice mijloace, firi acordul scris al redacfiei giautorului care de{ine dreptul de copiere

Metode de testare/Testing methodsMARIA SPATARU, VIRGINIA BURGHELEA, OVIDIU DUMITRESCU,MIRCEA IOAN POPESCU, GEORGE DRAGULESCU, ADINA MIHAILMetodd colorimetricd de testare a suspensii lor pe bazd de,alumind9i n is ip z i rconi ler . . .157Testing colorimetric method of alumina -zircon suspensionsM6thode colorim6trique pour tester les suspensions a base d'alumine et desil icate de zirconiumKolorimeter Methode f ur das Testen von Tonerde und ZirkonsandSusoensionen

SILVIANA MARICAMinerale gi roci: Gips - Selenit, de la resursd minerald pentru construcli i ,la o rnamente , gemd de co lec l ie g i b i ju te r i i . . . . : . . . . . . .166Minerals and rocks : Selenite - Gypsum, from a building mineral resourceto ornaments, collection gem and jewelriesMin6raux et roches: Gypse-s6ltinite, de la resource minerale pourconstruction aux ornaments, gemme de collection et bijouxMineralien und Gesteine: Gips-Selenit, vom Rohstoff zu Ornamenten,Zwi l ings-kr istal l Sammlungen und Schmucksteinen

Mani fes t i r i $ t i in f i f i ce . . . . . . . . . . . . . . . . . . . . .109 ,117,127,134,149,164, '169Simpozionul lnternafional in domeniul sticlei ISG/lCG 2005Shangha i - Ch ina . . .1682005' lnternai ional Symposium on Glass ISG/lCG'2005 Shanghai - ChinaA25-a Confer in ld de $t i infa Cimentului g i Betonului ,15-16 septembr ie 2005, Londra - Ang l ia . . . : , . . . . . . . . . . .13425tn Cemeht and Concrete Science, 15-16'n September, LondonConferin{d Interna{ionald: Durabil itatea betoanelor gi lucrdrilor din beton,26-28 septembrie 2005, Bucuregt i - RomAnia . . . . . . .149International Conference: Durabil ity of concretes and concrete works,Bucharest - RomaniaAl V-lea Simpozion Nalional: Pulberi Ceramice, 21 octombrie 2005,B u c u r e s t i - R o m A n i a . . . . . . . 1 1 75'h National Symposium: Ceramic Powders, 21tt Octobre 2005,Bucharest - Romania

Noi apar i l i i /News . . . . . 109 , 156Chimia l ian{ilor anorganici, autori: Prof. Maria Georgescu 9iProf . Annemarie Pur i . . . 169Inorganic Binders Chemistry, authors: Prof. Maria Georgescu andProf. Annemarie Puri

Din istoria construc{ii lor romAnegti: EMIL PRAGER - un model,au tor lng . N ico lae $ t .No ica . . . .170From the history of Romanian construction: EMIL PRAGER - a model,author: Eng. Nicolae $t.Noica

Monumente : MAndst i rea Ca lddrugan i . . . . . . . .175Monuments: Monastry Caldarugani

In memoriam: Ing. ION BERCA

Eratd

Palatul CotroceniBucuregt i , 1893

Arhitec!i:Paul Gottereau giGrigore Cerchez

1 3 9

REVISTA ROMANA OT MATERIALE , VOI. XXXV, NT.2,2OO5

MARIA SPATARU, VIRGINIA BURGHELEA, OVIDIU DUMITRESCUMIRCEA IOAN POPESCU,GEORGE DRAGULESCUUniversitatea POLITEHINCA Bucuregti

Lucrarea prezinti metoda de preparare, optimizare gicaracterizare din punct de vedere fizico-chimic asuspensiilor apoase pe bazd de alumini-nisipzirconifer.Caracterizarea suspensiilor s-a fdcut prin metodereologice 9i granulometrice. Viscozitatea gi diametrulmediu al particulelor influenteazi calitatea suspensiilorapoase ceramice, utilizate pentru fasonarea prin turnare informe poroase. Aceste suspensii sunt semifabricateutilizate la obfinerea anumitor produse ceramice cu bunecaracteristici refractare. Se propune o metodicolorimetrici de control al calitifii acestor suspensii.Metoda colorimetrici propusi nu a fost intdlniti inliteratura de specialitate pentru aprecierea calitifiisuspensiilor apoase ceramice.

l . lntroducere

Suspensiile apoase ceramice din alumind -nisip zirconifer sunt sisteme coloidale polidisperse,cu materii prime degresante. Pentru stabilitateasuspensilor gi impiedicarea depunerii degresantilorse folosesc mici adaosuri de electrolil i gi compugiorganici, cum ar f i : guma arabice (G.A.) ,carboximetilceluloza de sodiu (CMC), alcoolulpolivinilic (APV), amidonul, dextrina,etc. Realizareasuspensiilor ceramice implicd in principiu douip r o b l e m e [ 1 ] S i a n u m e :

1- Stabilirea unui sistem de preparare alsuspensiilor care sa asigure invariabilitateaproprietdlilor sale ;

2- Determinarea proprietd(ilor suspensiilor(nu numai din punct de vedere al curgerii, ci gi dinpunct de vedere al formdrii peretelui ceramic Ai aloperalii lor tehnologice ulterioare).

Suspensiile, pretabile fasondrii prin turnarein forme poroase, trebuie sd fie fluide, stabile, sdconfind pu[ind apa, un procent optim de adaosuriadecvate, dispersie granulometricd cores-punzdtoare formdrii de produse uniforme, curezistente convenabile in stare crudd .

Turnarea, degi este un procedeu mai pu{inproductiv ca strunjirea, are avantajul de a permiteoblinerea unei game foarte largi de produse cuforme complicate, de serie micd.

Colorimetria ca gtiinla a mdsurdrii culorii gi aaspectului acesteia, poate fi folositd pentru aprecie-

Metode de testare / Testing methodADINA MIHAIL

Institutul PASTEUR Bucuregti

l . lntroduction

Ceramic aqueous suspensions from alumina-zircon (zirconium sand) are polydisperse colloidalsystems with degresant raw materials.Forsuspension stability and degresants preventing tolay down are used small addi-tions of electrolytesand organic compounds, such as : Arabic gum( A.G.), sodium carboxymethylcellulose ( CMC ),polyvinyl alcohol (APV), starch, dextrine, etc. lnprinciple, the achievement of ceramic suspensionsinvolves two problems [ 1 ] :

1-The establisment to a system forsuspensions preparation which can assure theirinvariable propefiies;

2- Determination of suspensions properties(not only by point of view of flow, but also by point ofview of ceramic wall formation) and of subsequenttechnolog ical operations.

Suitable suspensions to shaping processthrough pouring in plaster moulds, must to be: fluid,stable, to contain little water, a best percentage ofadequately additions grain-size distribution(dispersion) according to mould of uniform products,resistance in raw (green) state.

The casting process, although is a lessproductive than lathing one, it has advantage topermit (allow) obtaining of a very large ganut(scale) of products with complicated shapes, insmall series.

The colorimery as the science of color

METODA COLORIMETRICA OC TESTARE A SUSPENSIILORPE BpzA Oe ALUMTNA $t Ntstp ZTRCONTFER

TESTING COLORIMETRIC METHODOF ALUMINA-ZIRCON SUSPENSIONS

The paper presents a preparing, optimizing andcharacterizing method from physical-chemical point ofview of aqueous suspensions based on alumina-zirconium sand. Suspensions characterization has madeby rheological and size distribution methods. Viscosityand average diameter of grains influence the quality ofceramic aqueous suspensions utilized for shapingthrough pouring in plaster moulds. These suspensionsare semi-products used for the obtaining of some ceramicproducts with good refractory characteristics. A checkcolorimetric method of these suspensions quality isproposed. The colourimetry, like as the rheology, permitsestimation of suspensions and oxide ceramic pastesquality. Proposed colorimetric method has not been met,into literature of speciality, for the aqueous ceramic

spensions estimation.

REVISTA ROMANA DE MATERIALE, VOI. XXXV, NT. 2,2005 157

rea cal i tat i i suspensi i lor gi pastelor ceramiceoxidice. Metoda colorimetricd propusd reprezintdansamblul de modele matematice 9i fizice caredefinesc perceperea obiectivd a culorii gi includeaparate gi tehnici de mdsurd, precum gi gestionareadatelor l2l. S-a utilizat un program specific decalculator Universe v.4.10 de la Hunterlab-Romegatest.

2. Parte experimentali

Pentru prepararea suspensiilor apoase s-auuti l izat alumind calcinatd de la Oradea (Romdnia),99,8% o-Al2O3, cu f inelea medie de 1,9 pm, 46 "/",nisip zirconifer din Australia ( ZrSiO+ ), cu fineleamedie de 117,9 pm, 51 "/" ,Tio2_ruti l , Merck, 3 7",adit ivi : CMC, G,A., APV sub formd de soluf ieapoasd de concentrafie 10 o/o, ape industriald,pH-7 ,4 , 1B %, [3 ] .

Pentru o stabilitate bund a suspensiei,amestecurile de materii prime s-au mdcinat umed inmori de porlelan cu bi le de po(elan aluminos,avdnd un volum de 5 | . Raportul intre amestecul depulberi : bile : apd a fost de 1 : 1 : 0,2. Mdcinareas-a fdcut timp constant de 5 ore. Compozifii lesuspensi i lor sunt prezentate in tabelul 1.

Pe suspensiile preparate s-au determinaturmdtoarele caracteristici: pH-ul, greutatea litricd,dimensiunea medie a part iculelor gi distr ibufiagranulometricd,viscozitatea.Valorile de pH s-auob[inut cu un pH-metru electronic de tip Orion EA940.

Dimensiunea medie a part iculelor gidistribu[ia granulometricd a materiilor prime gi asuspensiilor s-au determinat cu un analizorgranulometric cu laser, FRITSCH, tipul Analysette22. Viscozitatea suspensiilor s-a mdsurat cu unviscozimetru Rheomat RM 180 cu sisteme demdsurare de tip Brookfield. Testele de culoare s-aurealizal cu un spectrocolorimetru portabil MiniScanXE Plus, Hunterlab : i luminant Dos , port demdsurd LAV, geometrie Ool45o unghi de observare1 0 " , ( f i g . 1 ) .

measuring and its aspect can be used for qualityappreciation of suspensions and oxide ceramicpastes . Suggested colorimetric method representsthe ensemble of mathematical and physical modelswhich define the objective perception of color andincludes apparatus and measuring technics, as well ,data administration [ 2 ].A specified soft, Universev.4.10, from Hunterlab-Romegatest, was used.

2. Experimental

For preparing agueous suspensions, calcinedalumina from'Oradea (Romania) with 99.8 "/" CI-Af203 , 1.9 pm mean f ineness, 46y", zirconium sand,(ZrSi0a ), Australia, 117.9 pm grain-size average,51o/", Ti02 -rut i l , Merck quali ty, 3%, binders I A.G.,CMC, APV as aqueous solut ion of 10 oh, industr ialwater, with pH = 7.4, 18"/" were used [ 3 ]. Rawmaterials mixtures were wet grinded in corindonballs mil ls of 5 | in volume for a good stabi l i ty ofsuspensions, Powder mixture : balls : water ratiowas of 1 : 1 : 0.2.The grinding was done for 5 h ofconstant time.Composition of the suspensions arepresented in table 1.

The next characteristics : pH, volume weight,mean size of grains and their distributions, viscositywere determined on the prepared suspensions.

Tabelul 1

Fig. 1 - MiniScan XE Plus,

Com tion of the 10ns

SuspensieSuspension

SolidSolids

t % l

ApaWatert % l

Adaosur i /Adds [% ]

Total CMC GA APV

8 1 1 81 .BO 1 8 0.20 o . 1 2 0.08812 81.82 1 B 0 . 1 8 0.08 0 .108 1 3 81.78 1 B 0.22 o . 1 2 0 . 1 0814 81.70 1 8 0.30 o . 1 2 0.08 0 . 1 08 1 5 81.92 1 8 0.08 0.088 1 6 81 .88 1 B 0 . 1 2 0 . 1 2

1 5 8 REVISTA ROMANA DE MATERIALE, vol. XXXV, nr.2,2005

Pentru realizarea metodei colorimetrice decontrol al calit5fii acestor suspensii se vor parcurgeurmdtoarele etape :

chimice ce caracterizeazd suspensiile apoase;'

spectrale ale suspensiilor, printr-o procedurd demdsurd specificd probelor opace;

suspensiilor, in conformitate cu normele CIE: L*,d*, b*, C*, h*, unde L* este coordonata denumitdluminanfd(alb-negru) a culorii, o/o i a*-coordonatade cromaticitate pentru zona de culoare rogu-verde, o/o ; b*-coordonata de cromaticitate pentruzona de culoare galben-albastru, % ;C*-cromaticitatea sau puritatea culorii; h*-nuan[a;

admis/respins, prin intermediul diferenfelorpa(iale de culoare : AL*, Aa*, Ab*, respectiv acelor totale de culoare, exprimate prinintermediul a doud formule utilizate pe planinternalional : AF.x, 4E'* Diferenlele s-aucalculat fafa de doud etaloane colorimetrice:proba cu compozifia optimd oblinutd, respectiv ,media colorimetricd a probelor;

a toleranfelor teoretice admise, intre probe gietaloanele considerate ;

programului UNIVERSE v. 4.10, pentru a definidiagrama statisticd de calitate pentru suspensiilepreparate.

3. Rezultate 9i disculii

Caracteristicile generale ale suspensiilor cagranulometrie, pH gi viscozitate determinate laanumite temperaturi, sunt prezentate in tabelul 2.

Printr-o procedurd de mdsurd specificdprobelor opace, s-au achizilionat, stocat gi prelucratdatele spectrale ale suspensiilor, prezentate in figura2.

Din analiza spectrelor se constatd o serie deabsorblii specifice (minime ale spectrelor) mici,caracteristice probabil componenlilor de bazd aisuspensiilor.

The values of pH were obtained with an electronicpH-meter, type Orion EA 940. Mean grain-size andsize distributions of the raw materials 'and

suspensions were determined with a lasergranulometric analyser Fritsch, type Analysette 22.Suspensions viscosity were measured with aRheomat RM 180 viscosity meter having measuringsystems of type Brookfield Color tests wererealized with a portable spectrocolorimeter MiniScan XE Plus, Hunterlab : il luminant D65 , port ofmeasure LAV, geometry ool45o, angle of sight 100,(f is. 1).

The next stages went through fdr controlcolorimetric method achievement of thesesuspensions quali ty:

chemical data which characterize aqueoussuspensions;

and processing with a specified measureproceedings to opaque samples;

suspensions color, in keeping with CIELAB'76norms : L*, a*, b*, C*, h*, where L* is coordinatenamed luminance ( white-black) of color , "/" ia*- chromaticity coordinate for color zone red-green, o/o i b*- chromaticity coordinate for colorzone yellow-blua, % ; C*-chromaticity or colorpurity; h*-shade;

through the agency of color partial differences :AL*, Aa*, Ab*, respective of total ones : AE*,AE"r". The differences were calculateddepending on two colorimetric standards : thesample with the obtained optimum composition,respective, colorimetic mean of the samples;

methods, of theoretical tolerance limits, amongthe samples and thinked standards;

v.4.10 soft to define statistical diagram of qualityfor prepared suspensions .

Tabelu l2Caracteristici su /Characteristics of the 10ns

SuspensieSusoension

Greutate litricdVolume weight

l o / l lpH n

[Pa . s]D med.

lpmlT

locl

8 1 1 2800 7.81 1 .88 1 ,32 21 ,00812 2800 8 , 1 6 o.32 1 . 1 0 20.10813 2800 8 . 1 4 10.46 45.50 20.20814 2800 7.83 7.90 22.50 20.30815 2800 7.55 13,49 81,4o 20,40816 2800 8,43 7.37 2.42 20,00

REVISTA ROMANA DE MATERIALE, VOI. XXXV, NT. 2,2005 159

Deoarece este dificild aplicarea legiiKubelka-Munk, pe probele studiate, din lipsa unoretaloane spectrale, nu se pot determina cantitativconcentra[iile componen[ilor din date spectrale.Spectrele sunt paralele, ceea ce confirmd existenfaspeciilor chimice din care sunt formate suspensiilela diverse concentralii. Din spectre, s-au determinatparametrii standard internafionali CIELAB' 76 aiculorii suspensiilor : L*, d*, b* ( v.fig. 3 ), ca etalonconsiderdndu-se proba 814. Suspensia 814 s-aales ca etalon din considerente tehnologice [4 ].

in figura 3 se prezintd fereastra programuluiUniverse,"Master Color data", ce permitevtzualizarea denumirii probelor, a principalilorparametrii fizici care influen[eazd suspensia(D=diametrul mediu al particulelor,V=viscozitatea),a coordonatelor psihice rectangulare ale culorii( L*, d*, b" ), u diferen[elor totale de culoare -AE"r"

9i a gradului de alb-Wl61E.Diferenfa totald de culoare a fost calculatd

fald de un factor comercial (CF= 0,4) 9i un raportintre luminanld gi cromatici tate, | :c = 2l51.

Factorul comercial 0,4 este recomandatpentru probe care au criterii de acceptabilitateprintre cele mai severe .Toleranfele pa(iale deculoare s-au ales intre limitele t0,3.

Probele 811 gi 812, din punct de vedere alAE"r" sunt respinse. Datoritd depdgirii toleranleiparliale pe nuanfa galbend (Ab-) probele 811 9i B12sunt mai slabe calitativ decdt etalonul 814. Deasemenea, probele 812 gi 815, care au luminanlamai mare fala de etalon, ar putea sugera cdfolosirea numai a gumei arabice ca adaos defluidifiere/stabilitate nu este suficientd pentruasigurarea calitdlilor cerute suspensiilor pentruturnare.

Un alt criteriu de apreciere ar putea fi gradul dealb al probelor, Wlcre. Acesta se poate utiliza pentruprobele slab colorate. Din figura 3 se observd cd celmai mare grad de alb il prezintd proba B12 care estenecorespunzdtoare atdt din punct de vedere alproprietdlilor fizice cdt gi din punct de vedere alrezisten[ei mecanice in stare crudd.

Criteriile grafice de apreciere a calitafiisuspensi i lor 811-816, prin intermediul diferenfelorpa(iale, respectiv totale de culoare, de tip admis /respins, fald de 814, sunt prezentate in figura 4.

Figura 4 prezintd atributele culorii : luminanla( intensitatea ) - L*, respectiv, nuanla rogu/verdesau galben /albastru in doud planuri : planulluminanlei, cel mic din dreapta figurii gi planulnuanlelor ( cel mare din stdnga figurii ).

In planul nuanfei, Tn zona sa centrald sereprezintd printr-un pdtrat limitele de toleranldpa(iald 64x, Ab*.ln aceeagi zond apare o elipsdcare reprezintd limitele ce definesc zona deacceptabilitate a nuanlelor, din punct de vedere alAE"r" (al diferenlelor totale de culoare).Limitelecorespunzdtoare ale luminan{ei sunt indicate in

3. Results and discussion

General characteristics of the suspensionssuch as: granulometry, measured pH and viscosityat certain temperatures, are presented in table 2,

Spectral data of the suspensions wereacquisitioned, stocked and processed through aproceeding of specified measure to opaquesamples. These are presented in figure 2.

A series of small specified absorbtions(minimums of spectrum), probably, characteristicsof base compounds of suspensions is ascertainedfrom spectrum analysis. Becaube, the application ofKubelka-Munk law , on studied samples, is difficult,for lack of spectral standards, concentrations ofcompounds can not determine cantitatively fromspectral data. Spectrum are parallel, what confirmschemical species existence f rom which thesuspensions are formed at varied concentrations.International standard parameters CIELAB'76 ofcolor suspensions were determined from spectrum :L*, d*, b*(v . fig. 3), considering as standard 814sample. 814 suspension was chosen as standardfrom technological grounds [4 ] .

Figure 3 presents window ,,Master ColorData" of Universe soft which permits visualization ofname samples, of main physical parameters whichinfluence suspension ( G- mean size of grains, V=viscosity ), rectangular psychic coordinates of color( L*, d*, b*), total differences of color and degree ofwhite- Wl6lg.Total differences of color werecalculated depending on a commercial factor (CF=0,4 ) and a ratio between luminance andcroma-ticity, I : c = 2 t 5 l. The commercial factor (0,4 ) is recommended for the samples which havecriterion of acceptability through the most severe.The partial differences were chosen between + 0,3limits. From the point of view of AE"r., the 811 and812 samples are rejected. 811 and 812 samplesare qualitative thinner than 814 standard becauseof partial tolerance overfulfilment on yellow shade(Ab-). As well, 812 and 815 samples, which havethe luminance bigger than standard could suggestthat only using of Arabic gum as fluidity/stabilityaddition is not enough for assurance of askedqualities from suspensions for pouring. Anothercriterion of decision could be white degree ofsamples.This can be used only for thin colouredsamples.From figure 3 is observed that the greatestwhite degree is presented of 812 sample which isinadequate from point of view of physical propertiesand of mechanical resistances in green state.

Appreciation graphical criteria of B1 1-816suspensions quality, through the agenty of colorpartial differences, respective, total ones, of typepass/fail, depending on 81 4, are presented in figure4. Figure 4 presents color attributes : luminance(intensity), red/green and yellow/blue shades in two

160 REVISTA ROMANA DE MATERIALE, VOI. XXXV, NT. 2,2OO5

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REVISTA ROMANA DE MATERIALE, VOI.

Fig.4 - Criterii grafice de apreciere a calitdllisuspensiilor fafd de Bl 4l Appreciation graphicalcriteria of suspensions quality versus B 14.

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162 REVISTA ROMANA DE MATERIALE, vol. XXXV, nr. 2,2005

partea dreaptd. Prin aplicarea celor doud criterii deacceptabilitate sunt admise trei probe [etalonul 814in centru, respectiv, B1O ( notata cu 3 ) gi 816(notatd cu 6)1. Se observd cd proba 815 (notatd cu5) degi este in interiorul elipsei de tolerante totaleadmise se respinge din punct de vedere alluminanfei.

Aceeagi concluzie se poate trage gi din punctde vedere al toleranfelor pa(iale ( pdtratul ).

in procesele'tehnologice lndustriale se puneproblema elabordrii unor diagrame statistice decalitate, grafice care sd permitd'urmdrirea pe unnumdr mare de loturi (1SO ). in aceste diagrametrebuie fixate toleran[ele admise pentru parametriicare caraclerizeazd calitativ gi cantitativ sistemulanalizat.

Metoda colorimerticd propusd gi programul defirmd Universe v.4.10 permite analiza evolu[ieistatistice a calitafii suspensiilor pentru un numdrmaxim de 500 de probe. Un astfel de grafic seprezintd in figura 5.

In figura 5 se observd varia{iile parametrilor decalitate atdt pentru criteriul de tip admis/respins prindiferenfa totald de culoare , AE"r", cAt gi prin criteriuldiferen[elor pa(iale de culoare: AL*, Aa*, Ab".

Programul permite fixarea limitelor maximede acceptabilitate atdt pentru AE"r" cat gi pentruAL*, Aa*, Ab" : AE"r" = 0,4, AL*, Aa*, Ab" = + 0,3.

Graficul indicd clar probele admise saurespinse dupd aceste criterii de calitate.

Din datele experimentale se pot calculamediile parametrilor gi valorile abaterilor mediistandard. Acestea se pot stabili pentru fiecareprodus in parte gi reprezintd criterii mai reale decdtcele teoretice prezentate anterior.

Proprietd[ile fizice gi colorimetrice fata demedia probelor( SPM ) 9i fale de toleran[ele stabilitestatistic sunt prezentate in figura 6.

Pentru suspensiile analizate valoriletoleranfelor impuse sunt cele reate gi nu teoretice.

Aplicand criterii mai stricte de apreciere acalitdfii generate de prelucrarea statisticd a datelorexperimentale, proba 815 nu indeplinegte condifii leimpuse pentru parametrul AL". probele BtZ gi BtOsunt respinse pe coordonata b". pe coordonata a*sunt respinse probele B11 gi B12.

Criteriile grafice de apreciere a calitafiisuspensiilor fa{d de media probelor ca etalon, suntreprezentate in figura T

Reprezentarea graficd a evolu{iei statistice aculorii suspensiilor, in valori relative, fafa de mediaprobelor gi fafa de toleranfele stabilite statistic suntreprezentate in figura 8. Figurile 7 gi g suntreprezentdri grafice asemdndtoare cu figurile 4 gi 5.

plans: luminance plan(white/black), the small one,from right side of figure and plan of shades( the bigone from left side of figure). lnto shade plan, in itscentral zone, the limits of partial tolerances arerepresented through a square. An elipse, thatappears in the same zone, represents the limitswhich define acceptability zone of shades, frompoint of view of AE.r" (total differences ofcolor).Corresponded limits of luminance areindicated in the right side.

Through application of the two abceptabilitycriteria are admitted three samples[( 814 standardin centre, respective, 813(noted with 3) and816(noted 6)1. lt is observed, that 815 sample(noted 5), although is into side of accepted totaltolerences, is rejected because of luminance.

The same conclusion can be drawn frompoint of view of partial tolerances too ( the square).In industrial technological processes, it is put theelaboration problem of some statistical diagram ofquality which can permit the following on a bignumber of lots (150).ln these diagrams it must fixedthe admissed tolerences for parameters whichcharacterize qualitatively and quantitatively theanalized system.

The proposed colorimetric method andUniverse v.4.10 soft permit statisticat evolutionanalyse of suspensions quality for a maximumnumber of 500 samples. A such diagram is shownin figure 5.

In figure 5 are observed quality parametersvariations from point of view of settled colordifferences.The soft permits maximum limits ofacceptability fixing both for AE.r" and for AL", Aa*,Ab" : AEsr.= 0.4, AL*, Aa*, Ab*=+ 0.3.

The graph clearly indicates the passed orfailed samples after these criteria of quality.

From experimental data, parameters meansand values of standard mean deviations can becalculated.These can be settled for each productpartly and represent realer criteria than thetheoretical ones presented before.

Physical and colorimetric propertiesdepending on samples mean (SpM) and statisticalestablished tolerances are presented in figure 6.

For analized suspensions, required tolerancesvalues are the real ones and not the theoretic.Applying more strict appreciation criteria of qualitygenerated from statistical processing of experimentatdata, the 815 sample does not fulfil the imposedconditions on AL* parameter.Bl2 and 816 samplesare rejected on b* coordinate. On a* coordinate, 811and 812 samples are rejected. Appreciation graphicalcriteria of suspensions quality depending on samplesmean as standard, are represented in figure 7.

REVISTA ROMANA OE MATERIALE, VOI. XXXV, NT. 2,2005 163

Aplicarea criteriilor statistice pentruprelucrarea datelor experimentale se poate face curezultate bune pe un numdr mare de probe (120-1 4 0 ) .

4 Concluzi i

. Lucrarea a propus o metodd colorimetricdde control a calitafii suspensiilor ceramice,

. S-au testat doud seturi de criterii de deciziede tip admis/respins :criterii totale bazate pediferenlele de culoare intre AE*, AE"r. giprobe; criterii pa(iale bazate pe diferenfelepa(iale de culoare AL", Aa*, Ab*.

. S-a elaborat un grafic statistic de calitate cuajutorul ferestrei "Trend Color Plot".

. Metoda propusd este sensibila gi ladiferenfe extrem de mici.

. Cele mai bune suspensi i sunt B13 Si 814realizate cu adaosuri de CMC gi APV.

. Poate fi folositd in diverse faze ale fluxuluitehnologic pentru corec[i i [6 ] .

Lucrarea s-a realizat cu sprijinul S,C.ROMEGATEST din Bucuregti reprezentant unic alHunterLab in Romdnia, cdruia ii mulfumim cuaceastd ocazie.

BIBLIOGRAFIE

1. Satava V.- "Theorie de la fluidification des barbotinesc6ramiques et optimalisation du proced6 de coulage",L' I ndustrie Ceram ique'l 977, (7 07), 16l, 433- 437 .

2. Popescu M.l. -Tezd de doctoraVThesis-"Metodd pentrucontrolul desfSgurdrii reacliilor chimice gi biochimice"/Methodfor control of chemical and biochemical reactions unfurl-incurs de suslinere/ in course of sustain, Universitatea,,POLITEHNICA" din Bucuregti / University,,POLITEHNICA'of Bucharest;

3. Muntean M., Spdtaru M., Gavri l iu Gh.-,,Aqueous suspensionsof alumina-zirconium silicate mixtures and their rheologicalbehavior", Interceram 2001 (2),1 17-1 19;

4. Spdtaru M., Muntean M., Mihail A.- ,,Perete ceramic dinbarbotina aluminS-zircon"/'Ceramic wall from alumina- zirconsl ip casting", Romanian Journal of Materials, 2003, 33, (4),265-269.

Graphical representation of colorsuspensions statistical evolution, in relative values,depending on samples mean and statistical settledtolerances are shown in figure B.

Figure 7 and B are graphical representationsl ike f igure 4 and 5.

The application of statistical criteria forexperimental data processing can be made withgood results on a big number of samples(120-1a0 ).

4.Conclusions

. The paper proposed a control colorimetricmethod of ceramic suspensions quality.

. Two sets of type Pass/Fail decission criteriawere tested : total criteria based on colordifferences among : AE*, AE"r" andsamples; partial criteria based on partialdifferences of color , AL*, Aa*, Ab*.

. fi statistical graph of quality was elaboratedwith ,,Trend Color Plot" window assistance.

. The suggested method is also sensitive toextremely small differences.

. The best suspensions are realised B'13 withCMC and APV and 814 with AG in addit ion.

. lt can be used in different stages oftechnological flux for corrections [ 6 ].

AknowledgementsThe paper was achieved with the support ofS.C.ROMEGATEST f rom Bucharest, unitedrepresentative of Hunterlab in Romania, whom we

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5. x x x - ISO International Standard 105-J02;1997 AATCC TestMethod 1 10-1995, ASTME 313-'96",

6. Erginel N., Dogan 8., Ay N.-,, The stat ist ical analysis ofcoloring problems faced in ceramic floor tile industry'', EuroCeramics Vlll, Engineering Materials 2004, 264-268,1 693-1 696.

MANI FESTARI I NTE R NATIONALE

SEECChE 1l't South East European Congress of Chemical EngineeringBelgrade, Serbia and MontenegroSeptember 25-28,2005organized by:Association of Chemical Engineering - Serbia and MontenegroHellenic Association of Chemical Enineering - GreeceHungarian Chemical Society - HungarySociety of Chemists and Technologists of Macedonia - FYROMBulgarian Society of Chemical Engineering - BulgariaRomanian Society of Chemical Engineering - RomaniaFaculty of Technology and Metalurgy, Belgrade,www. ache.org.yu/SEECChE I /

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