Low cement, ultra-low cement and no cement castable miscellaneous talk

Low cement, ultra-low cement and no cement castable miscellaneous talk about:

Classification of low-cement, ultra-low-cement and cement-free castables: according to the provisions of ASTM, CaO contents of castables of different categories are classified as follows:

Calcium aluminate cement CaO content > 2.5% (weight)

Low CaO content of cement castable 1~2.5%

CaO content of ultra-low cement castable is 0.2~1.0%

No cement castable CaO content < 0.2%

In low cement, ultra-low cement and cementless binding castable, the dispersants used are mainly sodium silicate (sodium silicate), sodium phosphate (sodium hexametaphosphate, sodium tripolyphosphate, etc.). The function of dispersant is to increase the potential of colloid in castable and realize the dispersion of ultra-fine powder.Increase the fluidity of castable and reduce water consumption.Flocculant USES alumina cement (including high alumina cement, bauxite cement, pure calcium aluminate cement, etc.).Aluminum oxide releases Ca2+ and AL3+ ions slowly during hydration and is a good flocculant.

The setting and hardening of low cement and ultra-low cement castings are mainly achieved by the hydration of high aluminum cement and the setting of ultra-fine powder.

For low cement, ultra-low cement, no cement castable production of a variety of raw materials, aggregate clay clinker, bauxite clinker, fused corundum, plate alumina, and zirconium, and so on.The corresponding fine powder is also different.Currently, the most commonly used raw materials are alumina series, ultra-fine powder is mainly silicon powder recovered by tanggang ferroalloy factory, but also use AL2O3, Cr2O3 or zirconite ultra-fine powder, and 5~8% of the blue crystal stone as castable expansion agent.