资源描述：
《low-temperature_nucleation_of_magnesite_and_dolomite》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、Low-temperaturenucleationofmagnesiteanddolomiteByJ.C.Deelman,EindhovenWith4figuresinthetextDEELMAN,J.C.:Low-temperaturenucleationofmagnesiteanddolomite-N.Jb.Miner.Mh.,1999(7):289-302,Stuttgart1999.Abstract:BywayofduplicatinganexperimentdescribedbyLiebermann(1967)nucleationofmagnesite,huntitean
2、d/ordolomitehasbeenattainedattemperaturesbetween313Kand333Kandunderatmosphericpressure.EssentialtotheseexperimentsarefluctuationsinpHvalue.Afterinterruptinganexperimentafter1,3,5,or8ofsuchfluctuations,thechangefromoneormoremetastablephasesintothestablephase(magnesiteordolomite)couldbefollowed.
3、Atheoreticalexplanationfortheselow-temperaturesynthesescanbefoundinstabilityrelations.Ostwald'sRulestipulatesthenucleationofametastablephasebeforethatofthestablephase.Howeverfluctuationsofsufficientamplitudeanddurationarecapableofcrossingtheborderbetweenthemetastableandthestablefields.Asaresul
4、tthestablephasewillnucleatetogetherwiththemetastablephase.Conditionsopposingthesubsequentgrowthofthemetastablephase(suchastheslightlyacidicconditionsresultingfromperiodicallyintroducingCO2intothesolution)willfavourthecontinuedgrowthofthestablephase.Keywords:Magnesite,dolomite,huntite,low-tempe
5、raturesyntheses.MagnesiteThefirsttimeIobservedtheformationofmagnesitewasuponduplicatingofExp.No.57ofLiebermann(1967).InmyexperimentM-2110.918MolNaCl,0.0316MolMgCl2.6H2O,0.018MolMgSO4.7H2Oand0.020MolKCl(allchemicalsarereagentgrade)weredissolvedin3330cmdistilledwaterand2mMolCaCO3addedlater,wasdi
6、ssolvedbywayofbubblingCO2(industrialgrade)throughthesuspensionduring12hours.TitrationtopH=8.00tookplacewithdiluteammonia.Thenextphase,thegradualescapeofCO2fromthesolution,involvedheating3the500cmErlenmeyerflaskonanelectricplateto(inthiscase)333Kduring60hours.AsdescribedbyLiebermann(1967),theto
7、talexperimentconsistsofrepeating14timesthedissolutionphase,thetitrationandthephaseofheatingandgradualescapeofCO2.ThepHofthesolutionwasmeasuredeverytimeafterbubblingCO2throughit(pH=5,30to6,10inthisparticulartest),upontitration,andattheen
