Technique F Use of Crucible _1_1_1 - Chemistry LibreTexts

There are several types of crucibles that can be used for heating up materials. Possible types of crucibles are alumina, ceramic and porcelain. Skiptomaincontent Noheaders TechniqueF: Useof Crucible    Section1: PurposeofTechnique    Thistechniquedescribeshowtousea laboratory crucible to safely heat asample.     Section2:Operationsof Crucible     There are several types ofcrucibles that canbe used forheatingup materials. Possible typesof cruciblesare alumina,ceramicand porcelain. Mostlabsrequiretheuseofporcelaincrucibles. Porcelaincruciblesareglazedon the outside andinside,exceptthereis usually noglazeonthebottom. Cruciblesare meanttowithstand high temperatures of1020-1050oC. Cruciblescan heat up a variety of materialslikemetals (cooper, cobalt, etc.),hydrates and glass.     Use crucibletongs to pick-up cruciblesandpreventfingerprints.    Put crucibleon aclaytriangle thathasbeenplacedoveraniron ring attachedto astand and placedaboveaBunsenburner.     Makesurethatthecrucibleisdirectlyinthecenterofclaytriangletopreventitfromfallingover.  Afterthecrucibleisinplace,turnontheBunsenburnerflame(CAUTION: DONOT use immediate high heat onthecrucible) andbeginheating.    Section3: Maintenance ofCrucible    Theproperway toprepare thecrucible andlid istowashitwith laboratory water ONLY.  Useagentle flame and heat thecrucible fortwominutes oruntilwaterisevaporated.Thiswillallowthecrucibletimetobe completelywaterfreepriortomoreintenseheating.     Placethecleancrucibleandlidonthewiregauze. Donot placethecleancrucibleorlidonthecountertop. Cleanitagainifitisplacedonthecountertop.       Section4: SafetyPrecautions ofCrucible      DO NOT USE brokenorseverelydamagedcrucibles. Thermalshock canbreak thecruciblesiftherearealreadydefectsinthecrucible.    DO NOT overheatthecrucible. It  may cause materialsto spatterortoadhere thebottom  USEONLY crucibletongsto putonthelidwhenthecrucibleisoveraflame.  DONOT touchahotcruciblewithyourhands. It can burnyourhands.   NEVER putdown ahotcruciblehasbeenheatedon thecounter. USE a wiregauze.  NEVER directlypick-upthecrucibleafterithasbeenheatedup. Allowthecrucibletocooldownfirstbeforeusingcrucibletongs.  DO NOT stand near thecrucible,especiallywhenmaterialisheatingup.Makesuretousethelid before turninguptheflameon thematerial,asyou DO NOT want thematerialto becomeejectedtowardyou.  DONOT allow cold waterto interactwith the hot waterinsidethe crucible,itcancause thermalshock.   DONOT allow cold watertotouchthecrucibleafterithasbeenheatedup. Itcancausemechanicalshockofthecrucible.     Do’s    Do use crucible tongs to pickupandputdownthe crucibleand lidonthewirerack.            Do use crucible tongstoplacethelidon the heated crucible.           Do placethe lidand crucible after cleaning ontothe wire gauze and whenthe crucibleandlidarehot.                 Do not’s    Do not placethecrucibleand the lidonthecounterat ANYTIME duringthecleaningandexperiment.               Do not placethecrucibleonitsside. Makesureitiscentered onthe clay triangle.       https://www.indianscientificinstrument.com/laboratory-porcelainware/porcelain-crucible.html   http://www.morganmms.com/media/1766/cruciblecareuseandsafetyinformation-mgam.pdf   https://chem.libretexts.org/Ancillary_Materials/Demos%2C_Techniques%2C_and_Experiments/General_Lab_Techniques/Heating_a_Crucible_to_Constant_Weight  https://chem.libretexts.org/Ancillary_Materials/Demos%2C_Techniques%2C_and_Experiments/General_Lab_Techniques/Heating_a_Crucible_to_Constant_Weight