different tap-hole clays clay-gun, and plate viscometer for three Dataset produced by automated sand-rammer, Data in Brief

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Data in Brief

journalhomepage:www.elsevier.com/locate/dib

Data Article

Dataset produced by automated sand-rammer, clay-gun, and plate viscometer for three

different tap-hole clays

Joalet Dalene Steenkamp

^a,b,∗

, Charlotte Lindstad

^c

, Lars Lindstad

^c

aMintek, Randburg 2125, South Africa

bUniversity of the Witwatersrand, Johannesburg 0 0 01, South Africa

cElkem Carbon, Kristiansand 4621, Norway

a rt i c l e i n f o

Article history:

Received 8 October 2020 Revised 15 January 2021 Accepted 28 January 2021 Available online 30 January 2021 Keywords:

Tap-hole clay Workability Rheology Clay-gun Sand-rammer Plate viscometer

a b s t r a c t

In pyrometallurgicalfurnace operation, tap-holeclay is in- jected intothe tap-holeusinga clay-gun.The goals areto stopthemetaland/orslagfromflowingandtocreateaseal betweenthefurnacecontentsandtheenvironment.Therhe- ological properties of the tap-hole clay play an important roleinthisprocess.Somecommercialmanufacturersoftap- holeclayreporttheworkabilityindex(WI)oftheirproducts, basedonsand-rammertechnologyand standardisedproce- dures.Inthepaperpresentedhere,datasetsarepresentedfor threedifferenttap-holeclayswheretheeffectofthechoice in clay on the pilot-scale clay-gun was demonstrated and an automated sand-rammerwas utilised to determine the standard WI as well as an extended WI.A plate viscome- ter,utilisedinthecharacterisationofelectrodepaste,wasap- pliedaspotentialalternativetechnologyutilisedwhenchar- acterisingtherheologicalpropertiesoftap-holeclays.Inall three instances,the datacollection process wasautomated withrawand/orfiltereddata,availableasExcelspreadsheets, publishedinanonlinerepository.Forthepurposeofthispa- per, the data was analysed and presented as graphs orin

∗ Corresponding author at: Mintek, Randburg 2125, South Africa.

E-mail addresses: joalets@mintek.coza , joalets@mintek.co.za (J.D. Steenkamp).

Social media: (J.D. Steenkamp) https://doi.org/10.1016/j.dib.2021.106819

2352-3409/© 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

2 J.D. Steenkamp, C. Lindstad and L. Lindstad / Data in Brief 35 (2021) 106819

tables.Thedatawillbeoffutureuseforfurtherstudiesinto theeffectoftap-holeclayrheologyonclay-gunperformance.

© 2021TheAuthors.PublishedbyElsevierInc.

ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/4.0/)

SpecificationsTable

Subject Continuum mechanics

Specific subject area Characterisation of the rheological properties of two industrial and one experimental tap-hole clays applied when closing tap-holes of pyrometallurgical smelters

Type of data Tables, graph

How data were acquired Pilot-scale clay-gun (DDSA/O-M/MTK1160) Automated sand-rammer (R&D Carbon, RDC-194) Plate viscometer (Viscometer M11)

Data format Raw, filtered, analysed

Parameters for data collection For three different tap-hole clays, two industrial and one experimental:

• Changes in hydraulic pressure applied to the piston used to push the clay out of the barrel of the clay-gun

• Changes in sample height as a function of the number of rams for the automated sand-rammer

• Measured force as a function of plate height at a fixed plate speed for the plate viscometer

Description of data collection Three different tap-hole clays, two industrial and one experimental, were subjected to three different experimental techniques to determine their rheological properties. Experiments were conducted on the automated sand-rammer and plate viscometer in Kristiansand and on a pilot-scale clay-gun in South Africa. Room temperature conditions prevailed. During July 2018 the average temperature in Kristiansand was 20 °C [2] and in Johannesburg 10 °C [3]

Data source location Mintek

Johannesburg South Africa 26 °05 19 S 27 °58 39 E Elkem Carbon Kristiansand Norway

58 °07 40 N 7 °58 04 E

Data accessibility Repository name: Dataset produced by automated sand-rammer, clay-gun, and plate viscometer for three different tap-hole clays Data identification number: https://doi.org/10.17632/ddrn6hpkdj.2 Direct URL to data: https://data.mendeley.com/datasets/ddrn6hpkdj/2

ValueoftheData

• Thedataproducedhereisasubsequentstudyonworkdonein2017onthecharacterisation oftap-holeclayswhichwaspresentedatINFACONXVin2018[1].Allresultspresentedhere arenew.

• Thedataproducedisbeneficialtofurnaceoperatorsasitdemonstratestheeffectofchoicein tap-holeclayonclay-gunperformance.Thiscouldresultinimprovedtap-holeclayselection andsaferfurnaceoperation.

• Thedataproducedisbeneficialtoproducersoftap-holeclaysasitdemonstratesthetypeof technologiesavailabletocharacterisetherheologicalpropertiesoftap-holeclays.Thiscould resultinimprovedtap-holeclaydesignanddevelopment.

• The data will be useful for further studies into the effect of tap-hole clay rheology on clay-gunperformance, more specificallyforthe validationof mathematicalmodels usedto

Table 1

Average workability index per type of clay calculated for five data points per clay.

Clay A Clay B Clay C

Average WI 3 0.5 12.5 19.1

StDev 0.1 4.8 2.0

describetheeffectoftherheologicalpropertiesofthetap-holeclayonclay-gunbehaviour.

Thiscouldresultinimprovedclay-gundesign.

1. DataDescription

Fig.1containstheplugging pressure,asmeasured inthehydraulic systemoftheclay-gun, asa functionoftime forthethree differenttap-holeclays.Eachgraphrepresentsdatasets for 3to 5experimentsandthe filtereddataisavailableinthe repositoryasaMicrosoftExcelfile named“Fig.1”.

InTable1,theaverageworkabilityindex(WI)pertypeofclay,determinedbytheautomated sand-rammer according to standard methods [3,4], were summarized. The raw and analysed data setsare available in therepository asa MicrosoftExcelfile named “Table 1Fig. 2Fig.3 Fig.4”.

InFig.2,theeffectofthenumberoframsonthesampleheight isreportedforeachofthe different clays. The raw andanalysed data sets are available in the repository asa Microsoft Excelfilenamed“Table1Fig.2Fig.3Fig.4”.

The results in Fig.3, illustrates the effect oframming on the density ofthe clay samples.

The rawandanalysed datasetsare availableintherepository asaMicrosoftExcelfilenamed

“Table1Fig.2Fig.3Fig.4”.

TheresultsinFig.4,illustrates theeffectoframmingontheextended workabilityindexof theclaysamples.Therawandanalyseddatasetsareavailable intherepositoryasa Microsoft Excelfilenamed“Table1Fig.2Fig.3Fig.4”.

Fig. 5 containsthe sampleheight as a function ofnumber oframs for the three different clays, for different periods of standing time (time from filling of the crucible for the sand- rammeruntilconductingtheexperiment)rangingfromzero(initialtests)to24h.Therawand analyseddatasetsareavailableintherepositoryasaMicrosoftExcelfilenamed“Fig.5”.

TherawdatageneratedbytheplateviscometerisavailableintherepositoryasaMicrosoft Excelfilenamed “Fig.6aFig.7a” forClay Band“Fig.6bFig.7b” forClayC. Nodatawasgen- erated forClay A.Fig.6 containsan exampleofthe resultsobtainedwhensubjectinga single sampletomeasurementsintheplateviscometer.ForClayBandClayC,themaximumviscosity andassociatedshearratewerederivedfromtherawdataproduced.Thecalculatedaveragesper fixedplatespeedwereplottedinFig.7forClayB(Fig.7(a))andClayC(Fig.7(b)).

2. ExperimentalDesign,MaterialsandMethods

Thetap-holeclaysweresourcedfromthreedifferentsuppliersinSouthAfricaandlabelledA, B,andC.ClayAwasanexperimental claywithoutdatasheet.Clay BandClay Cwereavailable commerciallywithrespectivedatasheets.ClayBwasresinandwater-bonded,withmainlysilica as aggregate. Clay C was tar and resin bonded, with alumina asthe main aggregate. In both instances,themaximumparticlesizeoftheaggregatewas3mm.TheWIwasnotreportedfor eitherofthetwoclays.

Thepilot-scale clay-gun(DDSA/O-M/MTK1160)atMintekinJohannesburg,SouthAfrica was appliedinthetestwork.Themainpartsanddimensionsoftheclay-gun,appliedintheexperi- mentspresentedhere, areillustratedinFig.8.Thehydraulic cylinder(i) pushesapiston (ii)in

4J.D.Steenkamp,C.LindstadandL.Lindstad / DatainBrief35(2021)106819

Fig. 1. Plugging pressure, as measured in the hydraulic system, as a function of time for three different tap-hole clays: (a) Clay A, (b) Clay B, and (c) Clay C. Each graph represents datasets for 3–5 experiments.

Fig. 2. Average sample height per type of clay – calculated for 5 experiments – as a function of number of rams for (a) Clay A, (b) Clay B, and (c) Clay C. Error bars indicate standard deviation in measured height.

the cylindricalbarrel (iii), inorder to extrudethe clayinto the tap-hole. The hydraulic cylin- der isfilledwith(iv)oil,andtheclay barreltotheback ofthepiston with(v)airandtothe frontwith(vi)tap-holeclay.Whenpushingtheclaytowardsthetap-hole,pressurizedoilisap- pliedthroughapipe(vii)andnon-pressurisedoilreleasedthroughanotherpipe(viii).Whenthe pistonispulledback,inorderfortheclaytobeloadedintothebarrel,theprocessisreversed.

Pindicatesthehydraulic pressure(measuredinlinevii)appliedbythehydraulicsystemtothe clay andisreferred to asthe‘plugging pressure’.Forthis specificdesign, theclay pressureis onethirdofthemeasuredpluggingpressureduetotheclay-gunconfiguration.

Foreachexperiment,thepistonwaspulledbackedcompletelyandthebarrelfilledwith11–

17kgofclay,dependingonthetypeofclay.Theclaywasthenextrudedfully,asfortypicalclay- gunoperationswhenconductingapilotsmeltingcampaign,exceptthattheclaywassupported byanangleironattachedtothemouth-pieceoftheclay-gunduringextrusion,ratherthanbeing injectedintoatap-hole.Duringtheexperiment,thepluggingpressurewasloggedautomatically.

On eachclay, atleast5 experimentswere conductedandthe plugging pressure(measuredin thehydraulicsystem)wasloggedasafunctionoftime.

Theautomated sand-rammer(R&DCarbon,RDC-194)atElkem CarboninKristiansand,Nor- waywasusedtodeterminetheWIandrelatedinformation.Inthefirstsetofexperiments,the height ofthe clayasafunction ofnumberof ramswere determined for100 ramsper exper- iment. Five experimentsper claywere executed. The experimentswere executed accordingto themethodsdescribedinASTM-C181[4]andISO1927-3[5].Fromtheseresults,theWI(based on the fourfirst rams, calculatedin Eq.(1)), the extendedWI (based on all 100 rams, calcu- latedinEq.(2))andchangesinheightandchangesindensityperramasreportedbytheauto- matedsand-rammer.Thedensitycalculationisbasedontheweightoftheclay,measuredprior to theexperiments utilizingalaboratory scale,andtheheight measurements recordedby the

6 J.D. Steenkamp, C. Lindstad and L. Lindstad / Data in Brief 35 (2021) 106819

Fig. 3. Average density per type of clay – calculated for 5 experiments – as a function of number of rams (a, b); and the ratio of density after a specific number of rams to density after 100 rams, per type of clay, as a function of number of rams.

Fig. 4. Extended workability index per type of clay calculated for results in Fig. 2 (a); and the ratio of extended worka- bility index to workability index for each type of clay.

Fig. 5. Sample height as a function of number of rams for (a) Clay A, (b) Clay B, and (c) Clay C for different periods of standing time.

Fig. 6. Measured force and calculated viscosity as a function of plate height for (a) Clay B, and (b) Clay C at a fixed plate speed of 450 mm/min. Results are for one run on fresh clay only.

sand-rammer.TheheightparametersutilisedinEqs.(1)and(2)areindicatedinFig.9. WI= 100(^H1−H₄)

H₁ (1)

Where:

• WIistheworkabilityindex

• H₁ is theheight afterthe firstram,the firstmeasurement loggedby the automatedsand- rammer

8J.D.Steenkamp,C.LindstadandL.Lindstad / DatainBrief35(2021)106819

Fig. 7. The linear relationship between maximum viscosity and associated shear rate determined for (a) Clay B, and (b) Clay C at various plate speeds and on clay that was fresh or used.

Fig. 8. Schematic layout of the pilot-scale clay-gun (reproduced from Steenkamp et al. [1] ).

Fig. 9. Height after first ram (H 1) and height after x-number of rams (H x) where x represents 4 for Eq. (1) and 100 for Eq. (2) .

• H₄istheheightafterthefourthram WI_extended=100(^H1−H₁₀₀)

H₁ (2)

Where:

• WI_extended istheextendedworkabilityindex

• H₁ is theheight afterthe firstram,the firstmeasurement loggedby the automatedsand- rammer

• H₁₀₀istheheightaftertheonehundredthram

10 J.D. Steenkamp, C. Lindstad and L. Lindstad / Data in Brief 35 (2021) 106819

Fig. 10. Force (F) and height (h) parameters utilised in Eq. (3) and radius (R) parameter in Eq. (4) .

The plateviscometer (ViscometerM11) wasalso located at Elkem Carbon in Kristiansand, Norway[6].Theplateviscometerwasbuiltin-housebyElkemtostudytheviscousbehaviourof electrodepasteappliedintheFerroalloyandAluminiumindustries.Electrodepasteisacomplex material,similartotap-holeclay,andtypicallyconsistsof70–75%solidsandapitchbinder.The pitchbinderbehaves likea Newtonianfluid asits viscous behaviourisonly shearratedepen- dant,whilsttheviscousbehaviour ofthepasteisdependantonboththeforceappliedandthe shearrate. Given Elkem’s experience withusing both sand-rammers (manualand automated) andthe plateviscometer in the evaluationof electrode pastes, the option oftransferring the techniqueto theevaluationoftap-holeclayswasconsideredhere. Theinstrumentis operated withaconstantvelocityandisoftheconstantvolumetype.

Thetap-holeclaysampleispreparedandplacedonthestationaryplate.Thesampleisthen squeezed between two parallel plates,one stationary(on which the sample rests and which measures theforce applied)andthe other moving. The instrumentmeasures andrecords the changeinheight andcompressionforce appliedasa functionoftime, fora fixedplateveloc- ityandsamplevolume.Fromtheresultsobtained,theviscositiesandshearratesarecalculated basedonEqs.(3)and(4)respectively,aspublishedinTørklep[6].Theforceandheightparam- etersutilisedinEq.(3)andradiusparameterinEq.(4)areindicatedinFig.10.

η

= 2

π

^Fh5

3V² vp

(3)

Where:

•

η

^{isviscosity(kPa.s)}

• Ftheappliedforce(N)

• histhedistancefromtheplate(m)

• Vistheconstantsamplevolume(m³)

• vpisthefixedplatevelocity(m/s)

γ

=−

_3R

h²

_dh

dt (4)

Where:

•

γ

^{istheshearrate(/s)}

• Risthesampleradius(m)

• ^dh_dt istheinstantaneousplatevelocity(m/s)

Between 1 and 4 experiments were conductedper fixed platespeed, andbecause of the limitedavailabilityoftheclay,measurementsweredoneonfreshandusedclay.Noresultscould beobtainedforClayAasoncethe claywasremovedfromthesampleholderitflowedunder gravity instead of retaining its shape, thus sample preparation atroom temperature wasnot

possible.Astheflowratesofelectrodepasteduringoperationareverylowandtheinstrument wasdesignedforelectrodepaste,itcouldonlybeoperatedatratesupto450mm/min.ForClay B, measurementswere madeusingthe plateviscometeratplatespeedsfixed at1,10,40,70, and450mm/min. ForClay C,experimentswere conductedat platespeedsfixed at1,10,100, 150,225,and450mm/min.

CRediTAuthorStatement

Joalet Steenkamp: Conceptualization, Resources, Methodology, Investigation, Data Cura- tion, Formal analysis, Visualization, Original Draft, Project administration, Fundingacquisition;

Charlotte Lindstad: Methodology, Investigation,Review & Editing; LarsLindstad: Conceptual- ization,Review&Editing,Supervision,Fundingacquisition.

DeclarationofCompetingInterest

Theauthorsdeclarethattheyhavenoknowncompetingfinancialinterestsorpersonalrela- tionshipswhichhaveorcouldbeperceivedtohaveinfluencedtheworkreportedinthisarticle.

Acknowledgements

The authors wouldlike to thank theNorwegian University ofScience andTechnology and its industrial partnersand the Norwegian ResearchCouncil for financial support through the INTPART MetalProduction and Controlled Tapping projects. The authors would like to thank ElkemFerroveldforthesupplyoftap-holeclays.Thepaperispublishedwithpermission from MintekandElkemCarbon.

References

[1] J.D. Steenkamp , M. Mnisi , A. Skjeldestad , The workability index of three tap-hole clays, in: Proceedings of the Fif- teenth International Ferro-alloys Congress of 2018 hosted in Cape Town, South Africa, 2020 .

[2] Weather in July 2018 in Kristiansand, Norway. www.timeanddate.com/weather/norway/kristiansand (Accessed 1 Oc- tober 2020).

[3] Weather in July 2018 in Johannesburg, South Africa. www.timeanddate.com/weather/south-africa/johannesburg (Ac- cessed 1 October 2020).

[4] ASTM-C181Standard Test Method for Workability Index of Fireclay and High-Alumina Refractory Plastics, ASTM In- ternational, West Conshohocken, PA, 2003 2011 .

[5] ISO 1927-3Monolithic (Unshaped) Refractory Materials - Part 3: Characterization as Received, ISO, 2012 .

[6] K. Tørklep , Viscometry in paste production, in: Proceedings of the AIME Light Metals symposium of 1988 hosted in Phoenix, Arizona, U.S.A., 1988, pp. 237–244 .