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SUMMARY:Assessing the Envirnmental Sustainability of Reactive Magnesia and
  its Production - Djihan Hassan\, CUED
DTSTART:20131204T160000Z
DTEND:20131204T170000Z
UID:TALK48903@talks.cam.ac.uk
CONTACT:Anama Lowday
DESCRIPTION:The cement industry produces Portland Cement (PC) at a rate of
  3 billion tonnes/year\, contributing by over 5% to anthropogenic CO2 emis
 sions. The production of PC is an energy intensive and environmentally pol
 luting process and sustainability initiatives in its production have been 
 put forward. Among these initiatives is the development of alternative low
  carbon cements such as reactive magnesia (MgO).  MgO has been developed w
 ith a range of sustainability advantages over PC. However\, a major concer
 n is that the production of MgO is more energy intensive than PC per tonne
  of material produced. One way of overcoming this is to explore other prod
 uction routes that have the potential of being more environmentally sustai
 nable.\nMagnesia cement is currently produced by the calcination of magnes
 ite and from processing seawater and brine. Potential production routes fo
 r MgO include its production from magnesium silicate minerals and from mag
 nesium chloride (MgCl2) solutions – a main component of waste brine – 
 which are both targeted for their CO2 sequestration potential. The first p
 art of this research project investigates the environmental sustainability
  of current and potential production routes of MgO as compared to PC. The 
 second part focuses on optimising an experimental procedure for the produc
 tion of hydrated magnesium carbonates (HMCs) by examining the effect of di
 fferent parameters such as reaction temperature\, solution concentration a
 nd CO2 flow rate on the formed precipitates\; which are then calcined to p
 roduce MgO. \nThe environmental sustainability evaluation shows that the p
 roduction of MgO from magnesite and from seawater consumes more energy tha
 n the production of PC form calcite however\; the former production method
  has a lower carbon footprint than PC due to its CO2 sequestration potenti
 al. Moreover\, the production of MgO from magnesium silicates and MgCl2 so
 lutions also consume more energy than that of PC however depending on the 
 selected production route several will result in carbon negative MgO produ
 ction. The optimum experimental conditions for the production of MgO from 
 magnesium chloride solutions based tested parameters\, on crystal morpholo
 gy of the precipitated samples\, degree of reaction and CO2 content of the
  HMCs is reacting 0.5M MgCl2 solution at room temperature\, titrated at a 
 rate of 2.6 ml/min with a solution of ammonium hydroxide and sparged with 
 CO2 at a flow rate of 500 ml/min. The reactivity of the MgO produced by ca
 lcining the HMCs produced using this method was comparable to that of comm
 ercially available MgO samples.\n
LOCATION:Engineering Department - Lecture Room 3B
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