White cement mortar

[Dmendo]

Hi everybody.
I've found in a spanish artisan ovens forum an interesting mortar recipe. I translate literally what is said:

"Beeing so expensive and hard to find the refractory mortar I replaced it with a mix of white cement, lime and sand in proportions of 3 parts of cement, 2 parts of lime and 10 parts of sand. My oven is working more than one year and it remains in excellent condition. Grey cement have huge amount of iron salts wich in fire contact causes micro explosions ending up in cracks. White cement instead lacks such salts and has excellent adhesivity, together with a substantially lower cost than refractory mortar. Regards.."

3 cement, 2 lime, 10 sand

I think the white appearance of the joints is a plus of this recipe.
Regards.

[C5dad]

If my memory serves correct, the white is from Magnesium Oxide in higher concentrations. White concrete was used in the Trans American Pyramid in San Francisco. Most white cement comes from a facility in the high desert above Los Angeles. Neat stuff that is for sure. Not sure about the micro-bursts you speak of though.

[Tscarborough]

White portland cement is chemically not significantly different than grey cement. The manufacture is a little different, and it is always made in a dedicated plant. In all physical parameters there is no difference between white and gray concrete.

Interestingly, a nice buff colored portland cement can be made by introducing a spray of diesel fuel into the process.

The cement discussed in the article may not actually BE portland cement however, as that is not the only type of material used for the purpose.

[david s]

So is the white cement refractory or not?

[Tscarborough]

White Portland cement is not refractory, but it may be another type of cementious material that is.

[brickie in oz]

Ive heard lots of myths over the years about White Cement, or Brighton Lite as its called in Oz.
With all the jobs and uses of it Ive had, it seems react and behave like normal Portland cement, only 50% more expensive..

[Johnny the oven man]

A600 refractory cement is white'ish. Its a high alumina cement, 60%.