OREWORLD® High Alumina Cement is a rapid-hardening cement made by fusing at 1,500° to 1,600° C (2,730° to 2,910° F) a mixture of bauxite and limestone in a reverberatory or electric furnace or in a rotary kiln. It also can be made by sintering at about 1,250° C (2,280° F). Suitable bauxites contain 50 to 60 percent alumina, up to 25 percent iron oxide, not more than 5 percent silica, and 10 to 30 percent water of hydration.
OREWORLD® High Alumina Cement is produced by preparing raw material consisting of applicable bauxite and limestone, burning the raw meaterial and grinding into cement
The OREWORLD® High Alumina Cement can resist a high temperature at which a relative high temperature at which a relative high strength still remains.Its refractoriness increases with the content of CA2. Therefore it is suitable to make refractory concrete as a binder. Depending on the refractory aggregate(fireclay,high aluminum)used,the refractory concrete made of the cement can be used below 1400°C.
Although the early strenth of OREWORLD® High Alumina Cement develops rapidly,its later strength decreases. The rates of crystabls conversion and strength reduction relates to atmospheric temperature and humidity. In the saturated steam at 35°C，the conversion is complete in 28d and the strength decreases to the minimum, in the dry air below 20°C，the conversion is very slow. So the HAC is not suited to use in buiding engineerings. If it is used in construction, matters needing ttention given in the appendix GB201 must be followed . In order make use of strong points of HAC and overcome its weak point, cement scientists in the world have developed various modified HAC and overcome its weak point, cement scientists in the world have developed various modified HAC series: self-stressing cement, expansive cement, impermeable non-shrinkage cement,rapid hardening high strength aluminate cement. Special rapid hardening setting-controlled aluninate cement and so on. These alumina cements with special properties are used in rush repairs,quick construction antipermeability, leakage stopping , resistance to sulfate attack, winter constructions etc.We can supply some derivative products of alumina cement series according to requirements of special engineerings
Index |
Item |
CA-50 |
Al2O3, % |
≥50, ＜60 |
SiO2,% |
≤8.0 |
Fe2O3,% |
≤2.5 |
R2O, % |
≤0.40 |
Specific surface area, m2/Kg |
≥300 |
Setting time
Initial setting time,min
Final setting time,h |
≥30
≤6 |
Compression strength , MPa
6h
1d
3d |
20
40
50 |
Transverse strength, MPa
6h
1d
3d |
3.0
5.5
6.5 |
High Alumina Cement Construction method:
1. When preparing refractory concrete, fix on the aggregate according to using condition. Choose the proper capacity graduation to make maximum density. Be noted to match and adapt with cementing material.
2. According to certain proportion, add water and mix by man or machine into mortar and then begin casting construction. Use up the ready mortar within 40 min. Calcium Aluminate Cement’s hydration heat concentrate on early stage. Casting thickness should not exceed 3 cm each time. Water curing immediately when concrete goes hardening and the curing time should not less than 3 days.
3. When prepare expanding cement, Calcium Aluminate clinker’s dosage is 73-76%, CaSO4·2H2O dosage is 24-27%. When prepare self-stressing cement, the mixing ratio of CaSO4·2H2O should be increased.
High Alumina Cement Notice:
1. In order to avoid uncontrollable setting time, do not mix with Portland cement, lime etc of which separate out calcium hydroxide cementing material. Before use, clean all the mixing machinery.
2.
Steam curing to accelerate concrete’s hardening. The curing temperature should not higher than 50℃.
3.
Refractory concrete’s late strength decline big, design should according to the lowest stable strength. CA-50 bonded concrete’s lowest stable strength should be determined by the lowest strength of 7-14 days of demoulding sample curing in 20℃±1℃ water.
High Alumina Cement Packing:
by 50kgs bag. Store in shady, cool and dry place. Avoid stamp and mix with other substance.
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