Magnesia refractory dryout managing the risk of hydration

Transcription

1 text:templte Jounl 7/6/11 15:23 Pge 423 Mgnesi efctoy dyout mnging the isk of hydtion by J.D. Steenkmp*, H. Kotzé, J.G. Meye, nd J. Bnd* J o u n l Synopsis In 2002 the commissioning of n ilmenite smelte on the Noth Cost of South Afic ws extended by thee months due to the filue nd subsequent eplcement of the mgnesi-bsed efctoy lining. The lining filed due to the hydtion of mgnesi cused by n unexpected souce of wte. The incident esulted in significnt finncil losses nd polonged insunce clim which ws settled in As mgnesi-bsed efctoies e used extensively in both feous nd non-feous pplictions, the uthos of the ppe wnt to she the expeience gined fom this incident with othes. The ppe eviews the litetue vilble on funce stt-up pctices nd explins the hydtion of mgnesi using vilble souces. The incident is studied in moe detil, both techniclly nd economiclly, nd the costs incued e quntified in tems of the cost of the oiginl lining. The ppe concludes with lessons lened nd ecommendtions mde fo futue wok. The intention of the ppe is to stimulte open debte egding best pctices in peheting of funces lined pimily with mgnesi. Keywods Commissioning, hydtion, stt-up, mgnesi. Intoduction Duing wold-wide study conducted on metllugicl pocessing plnt stt-ups, Agwl nd Ktk1 found tht pyometllugicl plnt stt-ups e typiclly delyed by two mjo poblems: efctoy filues nd hndling of hot gses. Mgnesi efctoy mteil is utilized extensively in the feous3 nd non-feous4 industies to ensue the integity of the funce vessel contining liquid metl nd slg6. One of the disdvntges of mgnesi efctoy mteil is its tendency to hydte with subsequent loss in funce integity4. Kotze et l.10 epoted on typicl exmple of such dely which took plce in South Afic in Decembe The peheting of n ilmenite smelte lined with mgnesi efctoy mteil ws hlted due to the ingess of wte into the funce nd subsequent dmge to the efctoy mteil. Wte ingess ws cused by difficulties expeienced with the hndling of the hot gses geneted duing peheting. Extensive mesues should be tken to potect mgnesi efctoy mteil fom hydtion thoughout its life cycle. In this ppe the uthos investigte these mesues fom vious pespectives, including deepe look into the incident epoted by Kotze et l.10 Litetue pespective: hydtion of mgnesi Hydtion of mgnesi (mgnesium oxide o peiclse, MgO) in efctoy mteil occus when the mteil comes into contct with humid i, wte, o stem24. This exposue cn occu duing stoge, constuction, o opetion4. Thee e vious potentil wte souces in funce, such s mot o cstble, condenstion of humid i o off-gs, o wte tht unintentionlly entes the system (lekge fom cooling elements, fo exmple)21. The hydtion of mgnesi to mgnesium hydoxide (bucite, Mg(OH) 2 ) esults in n incese in volume of the bicks of up to 115%, due to density chnge21. Extensive hydtion leds to cck fomtion in the bicks nd cn subsequently led to disintegtion of the whole bick21. In industy, this mechnism is efeed to s dusting 24. On the othe hnd, the volume expnsion leds to bickwok movement which cn ffect the funce shell21. Hydted bicks should not be used duing constuction, no should funce be opeted if such bicks e pesent in the stuctue16. The optiml conditions fo hydtion of mgnesi efctoy mteil occu when wte is pesent t 40 C to 120 C21. This pocess is chcteized by the tnsfomtion of mgnesi into mgnesi hydoxide ccoding to the ection in Eqution [1]21: * Univesity of Petoi, Petoi, South Afic. Consensi Consulting, South Afic. Exxo Resouces, South Afic. The Southen Aficn Institute of Mining nd Metllugy, SA ISSN X/ Ppe eceived Aug. 2010; evised ppe eceived M P p e The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 111 JUNE

2 text:templte Jounl 7/6/11 15:23 Pge 424 Mgnesi efctoy dyout mnging the isk of hydtion The te of the ection depends on tempetue, the mgnesi content of the bick16, nd pessue (if wte is pesent in the vpou phse)18. The hydtion te with liquid wte is slow, but s soon s the wte penettes s stem the hydtion becomes fste16. Zhou et l.24 studied the hydtion pocess of typicl MgO, MgO-chome, nd MgO-spinel bicks in humid i, wte, nd stem t vious tempetues nging fom 60 C to 130 C. They found thee stges in which ection 1 occus: Stge 1 is contolled by the chemicl ection of Mg(OH) 2 fomtion Stge 2 is contolled by the diffusion though the Mg(OH) 2 film which foms ound the MgO Stge 3 o dusting hs much fste ection te thn stge 1 nd stge 2, theefoe it is ssumed to be contolled by the chemicl ection on the fst incesing ection sufce due to the mico-ccking t the gin boundies. To educe the possibility of hydtion of mgnesi efctoy mteil the following cn be done: The mgnesi efctoy mteil must be tnspoted in contine to potect the mteil ginst moistue16,3 Mgnesi bicks should be stoed inside stoge ooms whee it is dy, fee of fost, ventilted, nd with tempetue between 10 C nd 30 C. Stoge undeneth tpulin cove outside is not sufficient16 The bicks my not be stoed fo moe thn fou weeks pio to instlltion nd peheting. The lining should be potected ginst moistue duing instlltion nd peheting16 Bicks tht do not contin MgO should be exploited in es whee hydtion is concen. Altentively, sfe lime to silic tio of less thn one should be mintined fo mgnesi bicks, due to the fct tht lime inceses the likelihood of hydtion21 The use of cbon-bsed (wte-fee) mteil fo mming mixes is dvocted by Vescheue et l.21 Cooling devices should be tested unde pessue, outside the funce, to ensue tht thee e no wte lekges21 Vescheue et l.21 stipulte tht, duing the heting phse, funce tempetues should be elevted to 400 C s fst s possible (30 C/hou to 50 C/hou), theeby educing the possible hydtion time by ensuing tht ll wte is evpoted out of the bicks s fst s possible Hydtion due to filue of cooling device in funce must be voided by using the best cooling technology nd efctoy lining concept possible22 Mgnesi bicks could be coveed by ognic cotings3 o ective MgO-sites11 could be blocked with CO 2, SO 2 o slt solutions i.e. MgSO 4. Accoding to Sxen17, the extent of hydtion in bicks cn be tested by light tpping with metllic hmme. A metllic sound is n indiction tht the bick hs not been hydted nd is usble, whees dull sound indictes tht the bick hs been hydted nd is unusble. [1] A white coting (Mg(OH) 2 ) on the extenl fce of bick which is ssocited with bittleness, loose stuctue nd ccking, is sign of hydtion. The white outside lye my not dvesely ffect the sevicebility of the bicks, but if the white Mg(OH) 2 continues to the inside of the bick, the degee of hydtion is dvnced. Testing fo deepe bick hydtion is destuctive pocess, since the bick must be boken to pefom visul inspection16. Sxen17 sttes tht the degee of hydtion cn be detemined by loss in ignition (LOI). This is done by dying bick pieces t 110 C fo fou hous nd mesuing the weight. The died bick is then plced in funce nd heted fo 12 hous t 1050 C, fte which the weight is mesued gin. The diffeence in weight between the dy specimen nd the funce-heted specimen is n indiction of the degee of hydtion. Accoding to Kik-Othme8 Mg(OH) 2 decomposes themlly t ppoximtely 330 C, nd the lst tces of wte e expelled t highe tempetues to yield MgO, s shown in Rection [2]: [2] Although the ection is evesible, the dmge to the bicks in the fom of ccks hs ledy tken plce. Revesing this ection will theefoe esult in moe poous bicks11, which will led to n incesed nd deepe molten mteil penettion. In sevee hydtion, whee the bick hs ledy disintegted, thee is no wy of evesing the dmge. Litetue pespective: efctoy life cycle Figue 1 depicts the life cycle of typicl mgnesi efctoy bick. Hydtion of the mgnesi efctoy bick cn occu duing ny of the stges fte mnufctuing, but the instlltion nd peheting (dyout specificlly) stges e high isk stges4. Duing the instlltion nd peheting stges the bick undegoes sevel chnges20. Cuing is the fomtion of hydulic bonds. Cuing follows the plcement of the mteil nd is limited to wet instlltions of mgnesi efctoy bicks. In wet instlltions, mot is utilized s bonding gent between the bicks. The hydulic bond foms t mbient tempetue within 24 hous of plcement i.e. duing instlltion. Dyout is the emovl of moistue to ende the lining sfe to stt the pocess t lte stge. Bkeout is the fomtion of chemicl bonds t elevted tempetues. Hetup is the continution of the dyout o bkeout stges to the point whee the funce cn be put into opetion. Litetue pespective: dyout pocess The peheting of the efctoy is bsed on peheting cuve pescibed by the efctoy mnufctue9,16, who clculte te bsed on set of lbotoy tests nd knowledge of the stesses nd stins cused in the efctoy mteil by the peheting pocess2. Duing dyout some of the moistue contined in the efctoy bicks evpotes fom the hot fce combining with othe funce off-gses but most of the moistue moves fom the hot fce to the cold fce, eventully condensing ginst the cold steel shell nd dining fom the bottom of the funce shell16, JUNE 2011 VOLUME 111 The Jounl of The Southen Aficn Institute of Mining nd Metllugy

3 text:templte Jounl 7/6/11 15:23 Pge 425 Mgnesi efctoy dyout mnging the isk of hydtion Figue 1 Typicl life-cycle of mgnesi efctoy bick Figue 2 summizes the inputs, pocess steps, outputs, nd equipment involved in dyout pocess whee mesues e put in plce to pevent mgnesi efctoy fom hydtion by moistue condensing fom the off-gs nd by moistue condensing ginst the funce shell. Potble high velocity bunes e utilized extensively fo efctoy dyout in pyometllugicl smeltes4,10 nd in glss melting funces9,19. In the bunes, fuel is combusted in i supplied by fns ttched to the bunes9. Off-gs contining poducts fom the combustion nd dyout pocesses vent though n offtke nd condensed moistue fom the dyout pocess dins though din holes in the bottom of the funce shell14,20. The offtke is instlled t the highest position in the funce19 nd is initilly opeted without ny wte cooling, especilly when the off-gs contins moistue oiginting fom combustion poducts, i with high humidity, nd the efctoy mteil being died10. Fuels utilized in potble high velocity bunes include wood, col, ch16, Ssol gs10, ntul gs, nd oil7. Gs is pefeed16 becuse: The combustion ection is esy to contol s opposed to buning (pulveized) wood, col o coke esulting in good mss flow nd cicultion of hot gses nd theefoe contolled tnsfe of het to the efctoy bicks Gs buns with clen flme with little o no dition thus voiding poblems expeienced when buning oil due to ltent dition het tnsfe. Bunes e opeted with i to fuel tios much highe thn wht is equied fo stoichiometic combustion of the fuel. The excess i is utilized in foced convection het tnsfe pocess whee the scubbing ction of the hot, dy i tnsfes het to the efctoy lining9. The lyout nd plcement of the bunes nd fns e designed in such mnne tht the het tnsfeed fom the hot, dy i to the efctoy mteil is homogenous9. If stt-up buden is instlled pio to peheting, its lyout is designed to ensue homogenous het tnsfe fom the hot, dy i to the efctoy lining, but the buden is pefebly intoduced when the hetup pocess eched opeting tempetues5 (Figue 3). Funce pessue sensos monito the pessue inside the funce duing peheting. The funce pessue is kept constnt, positive, nd high enough to ensue tht the hot, dy i eches ll of the efctoy lining nd tht the off-gs vents fom the funce. The funce pessue is mesued with pessue sensos instlled in the funce oof nd contolled though chnging the position of dmpe in the off-gs vent9. Themocouples e utilized in vious pplictions duing peheting of the efctoy lining: To contol the combustion pocess by mesuing the tempetue of the hot, dy i in the funce nd djusting the i to fuel tio to obtin the desied tempetue19. The themocouples utilized in this ppliction e plced diectly in the funce tmosphee nd e theefoe expendble. Although one themocouple is utilized s contol themocouple, edundnt themocouples e instlled to ensue smooth tnsfe between themocouples should the contol themocouple fil. The themocouples e Figue 2 Anlysis of the dyout pocess Figue 3 Anlysis of the hetup pocess J o u n l P p e The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 111 JUNE

4 text:templte Jounl 7/6/11 15:23 Pge 426 Mgnesi efctoy dyout mnging the isk of hydtion instlled eithe though the funce oof7,10 o though tpholes15 with the hot junction close to the hot fce of the efctoy lining typiclly 25 mm15 but still in the funce tmosphee. A pyomete could lso be utilized to contol the combustion pocess5 To monito the dyout pocess ) by mesuing the tempetue of efctoy lining close to the hot fce typiclly mm15,16 but still in the efctoy lining nd b) by mesuing the tempetue of the funce shell in contct with the cold fce of the efctoy lining. The themocouples utilized in this ppliction e lso utilized duing noml opetions nd e theefoe pemnent. Duing dyout the themocouples instlled ne the hot fce of the efctoy bick e utilized s theshold themocouples. When the end of holding peiod in the pescibed peheting cuve is eched, the theshold themocouple is utilized to veify tht the tempetue in the efctoy lining eched stedy-stte nd tht peheting cn continue15,19. The themocouples instlled ginst the funce shell e utilized in monitoing the condenstion of moistue ginst the shell. Should the tempetue cycle between 99 C nd 107 C, moistue is still condensing ginst the shell. When the tempetue exceeds 107 C significntly it is sfe to ssume tht the efctoy lining is dy16. This method cn be utilized only in insultive linings whee no wte cooling is instlled on the funce shell To veify the qulity of design of the bune nd fn lyout by mesuing the hot fce efctoy tempetue t bune, which should be the highest tempetue, nd t the vent, which should be the lowest tempetue. Fo successful design, the diffeence between these two tempetues should be negligible20. Mesuements tken by funce pessue sensos nd pemnent themocouples e logged though the plnt contol system nd dtbses, nd mesuements tken by expendble themocouples e ecoded with potble ecode. Cse study In the following cse study, hydtion of n instlled mgnesi funce lining delyed funce commissioning by thee months despite the implementtion of sevel of the peventtive mesues descibed in the peceding pgphs. In the peiod peceding the commissioning of 36 MW DC funce lined with mgnesi bicks, excessive pecutions wee tken duing efctoy instlltion to mitigte the isk of hydtion. These included stoing the efctoies in dy e, emoving the efctoy pllet wpping only s the bicks wee needed, eecting tpulin immeditely bove the funce oof to seve s bie between the instlled efctoy lining nd cooling wte piping bove it, nd llowing no wte on the immedite levels ound the funce tpholes nd oof. Actul dyout of the bicks ws ledy conducted t the mnufctuing site of the efctoy supplie; moistue emovl fom the bicks ws theefoe not equied. Also, being dy instlltion, no wet mot ws used. Duing Decembe 2002, peheting (hetup) of the funce commenced. The two pimy objectives of the peheting stge wee: Limiting the tempetue gdient between the hot nd cold fces of the efctoy bick. Duing the peheting stge the efctoy bick hot fce ws in contct with the hot gses, while the cold fce ws in contct with themlly conductive cbon pste, which filled the gp between the bick nd wte cooled funce shell. This cetes theml gdient long the longitudinl xis of the bick nd, since mgnesi undegoes theml expnsion, mechnicl stesses e induced: moe so t the hot fce thn t the cold fce. When excessive, these stesses will led to ccking of the bick. A slow hetup cuve, s pescibed by the efctoy supplie nd designe, nd illustted in Figue 4 ws theefoe followed. Themocouples hnging fom the oof into the funce intenl volume nd mesuing the intenl gs tempetue wee used s efeence tempetue. The undelying ssumption ws tht the intenl gs tempetue is equl to tht of the efctoy hot fce. Reching 800 C on the hot fce of the heth bicks befoe intenl tempetues e elevted to tempetues whee the fist liquid ion will fom. Accoding to the efctoy instlltion design of the given funce, the spcing povision between the instlled bicks would be completely closed when the bicks eched 800 C. Reching this condition befoe liquid ion is bought into contct with the heth would pevent ion penettion into the heth. Howeve, het tnsfe to the heth hot fce ws hmpeed by the pesence of 150 mm thick scificil lining, nd n initil ion buden of sevel hundeds of tons. Both scificil lining nd initil buden coveed the full e of the heth. To ovecome this constint, two holding peiods wee included in the pehet cuve (Figue 4), thus giving the efctoy lining soking time nd the heth time to ctch up with the efctoy wlls. Methne-ich Ssol gs with n vege composition s shown in Tble I ws used fo peheting. The Ssol gs ws combusted with excess i t mbient tempetue nd humidity. The combusted gs nd heted i wee vented fom the funce vi the off-gs duct. Being designed to hndle high tempetue off-gses duing opetionl conditions, the duct hd foced wte cooling coils unning long its extenl sufce nd coveing its full length. Duing the peheting stge of commissioning, the following constints which wee often opposing, equied mngement by the commissioning tem: Figue 4 Refctoy hetup cuve s pescibed by the supplie 426 JUNE 2011 VOLUME 111 The Jounl of The Southen Aficn Institute of Mining nd Metllugy

5 text:templte Jounl 7/6/11 15:23 Pge 427 Mgnesi efctoy dyout mnging the isk of hydtion Tble I Avege s-nlysed composition of methne-ich Ssol gs used fo peheting CH4 A H2 CO N The theml input into the funce hd to be contolled ccoding to the peheting te pescibed in Figue 4 to pevent excessive tempetue gdients within the bicks Sufficient het hd to be supplied to the heth to ise the tempetue mesued by the tempoy themocouples locted on the heth hot fce to 800 C despite the pesence of the scificil lining nd initil buden A positive pessue hd to be mintined within the volume of the funce. This ws mintined by utilizing the pessue contol vlves of the off-gs ducting The tempetue of the off-gs duct cooling wte hd to be limited below 70 C s pescibed by the equipment designe to pevent the initition of sufce boiling within the foced cooled wte chnnels Upon eching elevted tempetues, the welding sems ttching the wte cooled coils to the off-gs ducting poved to be of infeio qulity. Welding sems opened up t elevted tempetues, nd closed gin with incesing wte cooling on the duct. At the time, it ws unknown whethe the welding ccks extended into the mothe steel, hence llowing wte penettion into the funce. Appoximtely 36 hous fte commencing with the pehet, the pocess ws hlted due to excessive wte dmge to the mgnesi efctoies. The wte oiginted fom the humid i utilized fo combustion nd its subsequent condenstion within the wte cooled duct (the contibution fom the combustion poducts of the Ssol gs ws, in this instnce, negligible). Humidity nd tempetue edings fo the dys ove which peheting wee conducted e given in Figue 5. Tempetues nged in the high twenties, while humidities wee close o equl to 100% ove the peiod. This combintion esults in humidity lod to the intenl funce bove 15 g/kg dy i ove the lst few hous of the hold t 200 C nd the subsequent initil incese in intenl funce tempetue. At the typicl i consumption tes of m3/h, this esults in kg of wte pe hou. While pesent s vpou within the heted funce volume, mjo pt of this wte condensted long the inside of the wte-cooled off-gs duct, which ws kept cool fo the esons s given bove. The cost of unsuccessful isk identifiction in the instnce of the cse study ws not only eplcement of the complete efctoy lining, but lso the consequentil loss in poduction. Relining the funce took thee months one month to demolish the hydted lining, nd poduce nd delive the new lining; one month to instll the new lining, nd one month fo peheting. Although the ctul finncil figues e popiety, the finncil implictions of the incident cn be expessed in tems of the cost of the new lining s indicted in Tble II. Peventing efctoy hydtion: mngement pespective In the cse study descibed bove, hydtion of mgnesi efctoies ws known isk. Despite this, it still occued. It ws theefoe not filue of ecognising the isk, but filue of ecognizing ll the souces of the isk nd blncing the pobbilities of the multitude of isks typicl of commissioning pocess. Bsed on the expeience of mngement mesues, which woked well, s well s lessons lened duing the cse study, the following e listed s key fctos in enbling isk nd isk souce identifiction nd ecognition within commissioning envionment: Following multidiscipliny ppoch. Duing commissioning of complex funce system (funce, feed system, downstem mteil hndling equipment, sevel oiginl equipment mnufctues, etc.), multitude of tsks must be executed nd isks mitigted hydtion of the bicks being only one of them. No one peson cn cove the complete scope. Individuls nd tems need to be integted nd coodinted to ensue no ovelps o gps in esponsibility. Figue 5 Ambient tempetues, humidities nd dew point inside the funce duing the peheting peiod. The ltte tkes into ccount the incesing volume flow though the funce with incesing tempetue Tble II Finncil impliction of cse study expessed in tems of cost of new lining Cost to demolish hydted lining & instll new lining : 2:3 cost of new lining Cost of loss in income : cost of new lining 25:3 Totl cost : cost of new lining 10:1 J o u n l P p e The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 111 JUNE

6 text:templte Jounl 7/6/11 15:23 Pge 428 Mgnesi efctoy dyout mnging the isk of hydtion Compiltion of systemtic commissioning pln ptitioned into the diffeent phses of commissioning, ech phse setting out the citei tht must be eched befoe pogessing to the next phse. These citei lso seve s cle gols. Compiltion of this pln well in dvnce llows time to gthe infomtion (conducting litetue study on typicl peheting pctices s is povided elie in this ppe will dd temendous vlue) nd thoough evlution of wht if scenios outside the pessuized commissioning envionment. Poblem solving needs to be ppoched with conscious effot to not cete futhe poblems while solving othes. Evey oppotunity to len fom pevious expeiences must be utilized, whethe this be fom expeienced individuls, peviously compiled intenl epots, etc. Evey expeience is lso n oppotunity to contibute to the knowledge bse of the compny. A dily log of key pmetes, thought pocesses, nd esons seve s vluble efeences fo futue wok. A fine blnce between diving fo timeous stt up nd mitigting the isk of ievesible dmge needs to be mintined. As pt of such isk evlution, the enegy levels, motivtionl stte, nd letness of the commissioning tem should be tken into ccount. Risk ecognition depends stongly on these chcteistics. Conclusion Although compnies in Southen Afic commecilly poduce nineteen types of commodities t moe thn sixty smeltes25 vey little litetue is vilble on funce stt-up on ny type of lining. As funce stt-up events e not something tht occus on egul bsis in continuous smelting opetions, shing expeiences, nd moe impotntly the lessons lened fom these expeiences, would llow fo constuctive debte on best pctices in funce dyout nd hetup. Keeping in mind the significnt costs involved in filed stt-up, best pctices in funce stt-up is something the pyometllugicl industy could benefit fom significntly. Refeences 1. AGARWAL, J.C. nd KATRAK, F.E. Economic impct of sttup expeiences of smeltes. Advnces in Sulphide Smelting: Poceedings of the 1983 Intentionl Sulphide Smelting Symposium nd the 1983 Extctive nd Pocess Metllugy Meeting, vol. 2, 1983, pp AINSWORTH, J.H. Clcultion of sfe het-up tes fo steelplnt funce linings. Cemic Bulletin, vol. 58, no. 7, pp BUHR, A. Refctoies fo steel secondy metllugy. CN-efctoies, vol. 6, no. 3, 1979, 1999, pp DONALDSON, K.M. et l. Design of efctoies nd bindings fo moden high-poductivity pyometllugicl funces. Poceedings of the Intentionl Symposium on Non-feous Pyometllugy Tce Metls, Funce Pctices nd Enegy Efficiency, 1992, pp GLASTYAN, G.A. High-speed het-up of open-heth funces fte cold epis. Metllugy, no. 5, My 1966, pp GARBERS-CRAIG, AM. How cool e efctoy mteils? Jounl of the Southen Aficn Institute of Mining nd Metllugy, vol. 108, no. 9, Septembe 2008, pp KIRKHAM, A.D. Het up of funces old nd new. Glss Technology, vol. 26, no. 6, 6 Decembe 1985, pp KIRK-OTHMER. Encyclopedi of Chemicl Technology, 5th edition, vol. 15, 2005, p KOPSER, G. Funce het-up techniques dpt to melte design KOTZE, H. et l. Ilmenite smelting t Tico SA. Jounl of the Southen Aficn Institute of Mining nd Metllugy, vol. 106, Mch 2006, pp LANSER, VON P. nd SKALLA, N. Hydttionsbeständige mgnesitsteine. Rdex-Rundschft, vol. 41, no. 6, LAUZON, P., RIGBY, J., OPREA, C., TROCZYNSKI, T., nd OPREA, G. Hydtion Studies on Mgnesi-Contining Refctoies, Unite, 2003, pp LAYDEN, G.K. nd BRINDLEY, G.W. Kinetics of vpo-phse phse hydtion of mgnesium oxide. Jounl of the Ameicn Cemics Society, vol. 46, no. 11, 1963, pp LI, Y. nd ARHTUR, P. Yunnn Coppe Copotion s new smelte Chin s fist Issmelt. Yzw Intentionl Symposium, Metllugicl nd Mteils pocessing: pinciples nd technologies, vol II: high-tempetue metls poduction, 2003, pp MCCLELLAND, R. et l. Commissioning of the Ausmelt led smelte t Hindustn Zinc. TMS Fll Extction nd Pocessing Division: Sohn Intentionl Symposium, no. 8, 2006, pp RHI REFRACTORIES. Refctoy Bicks in Roty Kilns, Instlltion Guide, RHI Refctoies, Englnd SAXENA, J.P. Refctoy Engineeing nd Kiln Mintennce in Cement Plnts, Tylo nd Fncis Goup, United Kingdom, 2003, pp SEVERIN, N.W. Dyouts nd hetups of efctoy monoliths. Advnces in Cemics, vol. 13, 1985, pp SEVERIN, N.W. Contolled-tempetue dyouts of efctoy linings. Cemic Engineeing nd Science Poceedings, vol. 16, no. 1, 1995, pp SEVERIN, N.W. Refctoy dyout how cn we impove it? Cndin Cemics, Febuy 1998, pp VERSCHEURE, K., KYLLO, A.K., FILZWIESER, A., BLANPAIN, B., nd WOLLANTS, P. Funce Cooling Technology in Pyometllugicl Pocesses, The Minels, Metls nd Mteils Society, WALLNER, S., FILZWIESER, A., nd KEICKER, J. Some spects fo the use of wte cooled funce wlls Wte the best efctoy?, RHI AG Vienn, Vienn Austi ccessed on 18 Mch ZHOU, A., TROCZYNSKI, T., OPREA, G., RIGBY, J., nd LAUZON, P. Hydtion kinetics of mgnesi-bsed bicks, Ameicn Cemic Society, Cnd JUNE 2011 VOLUME 111 The Jounl of The Southen Aficn Institute of Mining nd Metllugy