Re: MgO Reduction

Yes, of course supplementary cementitious materials can be used to dilute the MgO content of cement. Other measures are to ensure the clinker is rapidly cooled in order for any MgO to be present in small crystals of periclase.

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Re: MgO Reduction

We have commissioned recently one plant in Karnataka, INdia where the MgO in the clinker is around 4.5%.

As Mr.Clark said you need to cool the clinker quickly that means you need to have new cooler technology. When first the cement is tested it failed the autoclave expansion. Then we increased the clinker liter weight and restrict the freelime to max.2%. This has given good results the passed the auto clave test.

Definitely the addition of limestone or pozzolona or fly ash will give good results.

Basavaraj Shiggavi 

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Re: MgO Reduction

Dear Mr.Basavaraj,

Definitely controlling free lime will reduce autoclave expansion as autoclave expansion is cumulative effect of periclase and free lime content.Increase in liter weight will not reduce periclase content.Better technical option is to reduce burning zone temperature by using suitable mineralizer and increase reactivity of raw mix by finer grinding.The measures will reduce periclase content and also reduce free lime content.

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Re: MgO Reduction

Hi

I feel that there is no fixed % for Mgo content to create expansion. Because it mainly depens on the size of the MgO particles and in what form ( free or combined with other minerals) it is available in the rawmaterial. There are plants which are running with 5% MgO in the clinker with no expansion and plant are getting expansion with 2% MgO in the clinker ( with the same cooler).

As suggested, repid cooling and finer grinding wii help

Regards

Vinayak

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