Dear Michel

some national standards I know of are :

Hungary 0.6% , India 1.0% , Rep. of Korea 0.5% , Syria 1.0% , Taiwan 0.5% , Turkey (Fe2O3 + Mn2O3) 0.8%

These information might have been updated I dont know but it helps as indicators that some standards specify limits for both parameters .

Hamza

Hello Hamza,

 If both lightness and Fe2O3 content are specified then, to comply with the standard,  you will need to produce cement that meets both specifications (even if you easily meet the specification for one or the other).

Also, not only does the quantity of iron in cement affect its colour, the oxidation state of the iron has a big effect too. Some plants producing white cement actually adjust the main burner flame so that it is firing directly on the clinker bed. This causes local reducing conditions which lower the oxidation state of the iron to the lighter Fe+2 rather than the darker Fe+3.

Regards,

Ted.

Dear Ted

Thanks for your explanation but as Michel wrote if you have a constraint on degree of whitness then a limit on ferric content will be redundant do you agree with that ?

Hamza

Hello Hamza,

No, Fe2O3 will not be redundant because whiteness is directly linked with Fe2O3 content. So, even if the only constraint in the standard is whiteness, you will still need to control the Fe2O3 content to control whiteness.

Regards,

Ted.