CA-50 for castables up to 1,450°C, CA-70 for 1,450-1,600°C, and CA-80 for 1,600°C and above - grade the binder to the castable's service temperature, never to price. Here's the thing about buying calcium aluminate cement: it looks like ordinary cement, costs like a specialty product, and performs completely differently. Calcium aluminate cement (CAC) is the binder behind most refractory castables - it sets fast, gains strength fast, and keeps its structure where Portland cement turns to mush. Pick the wrong grade and your castable underperforms at the top end, or costs twice what it should
What Is Calcium Aluminate Cement?
Calcium aluminate cement is a hydraulic binder whose main minerals are calcium aluminates - CA (CaO·Al₂O₃) and CA₂ - rather than the silicates that dominate Portland cement. It sets by hydration like Portland, but the chemistry is different: no C₃S, no C₂S, no free lime released during hydration. That's what makes it refractory-grade.
What buyers actually see: a grey or buff powder, bagged at 25 kg or 1,000 kg, with an Al₂O₃ number on the COA. That number is the grade.
CAC does three jobs in a castable. It provides green strength so the lining holds shape before first heat. It releases no excess lime that would soften at high temperature. And it develops strength fast - one-day strengths of 40-70 MPa are normal, which is why relines go back online quickly.
CAC has been made since the early 1900s, originally for high-alumina construction cements, and the refractory industry adopted it because nothing else binds a castable past 1,200°C without softening. Fifty years on, it's still the standard - nobody has beaten the chemistry.
For the chemistry in more depth, our explainer on calcium aluminate cement walks through why the mineralogy matters.
Calcium Aluminate Cement Grades: What the Numbers Mean
CAC grades are named by alumina content. CA-50 carries roughly 50% Al₂O₃, CA-70 about 70%, CA-80 above 78%. The alumina level drives everything: refractoriness, cost, and the temperature ceiling of the castable it goes into.
CA-50 is the workhorse. It binds castables for the 1,200-1,450°C range, sets reliably, and is the cheapest refractory-grade CAC you can buy. Most general-purpose castable plants run CA-50 as their standard binder.
CA-70 is for castables that face 1,450-1,600°C. The extra alumina lifts the refractory ceiling and improves resistance to slag and alkalis. It costs more than CA-50 and is worth it only where the mix actually needs the headroom.
CA-80 is the top grade - 1,600°C and above, low-iron, used in premium castables and where purity matters. We also supply white CA-80 for special applications.
Iron content is the second number to check. Standard CAC carries Fe₂O₃ around 1.5-2%; low-iron grades hold it under 0.5%. Low-iron calcium aluminate cement keeps castables from discoloring and holds up better in reducing atmospheres. If your spec mentions low iron, that's a grade premium, not a marketing label.
How to Match CAC Grade to Your Castable
Rule of thumb: the binder should never be the weak point of the mix. Grade the CAC to the castable's service temperature, not to what the formulator had in stock.
For castables up to 1,450°C, CA-50 does the job. This covers most boiler linings, furnace walls, and general purpose mixes. Spending on CA-70 here buys nothing except a higher bill.
For 1,450-1,600°C castables, CA-70. This is kiln hood, burner block, and steel plant territory - the zones where a weak binder shows up as premature spalling. If you're formulating a high alumina castable, CA-70 is the usual partner grade.
For 1,600°C and above, or where the mix demands low iron, CA-80. Premium castables for aluminum melting and petrochemical duty usually specify it.
One trap we see: buying CAC on price per ton alone. Two CA-70 lots from different mills can differ in setting time and early strength by enough to change your production schedule. The COA must show Al₂O₃, Fe₂O₃, SiO₂, CaO, setting time, and 1-day/3-day strengths - and we send one with every lot.
Where Calcium Aluminate Cement Goes Beyond Castables
Castables are the main consumer, but CAC shows up in several other places. Ramming mixes and gunning materials use it as the binder. Refractory mortars and repair patching mixes rely on its fast strength gain. Precast shapes - burner blocks, tundish boards, ladle covers - use CAC-bonded low-cement mixes. Outside refractories, CAC serves fast-setting floor systems, sewer linings, and high-early-strength repair work where ordinary concrete can't cure fast enough.
That last point matters for sourcing. A construction buyer and a refractory plant need different things from the same CAC mill: different fineness, different consistency, different COA priorities. Tell your supplier what the cement is for - a refractory-grade CAC spec is tighter than a construction-grade one. Our full monolithic refractory range shows the castables this binder goes into.
Sourcing Calcium Aluminate Cement from China: What to Verify
China is the largest CAC production base, and most global buyers end up sourcing here. The checks that matter:
First, the mill, not the trader. Ask for the production license, ISO 9001 certificate, and the plant's raw material source. Chinese bauxite quality varies by region, and the mill's bauxite supplier determines what your calcium aluminate cement can achieve.
Second, the COA format. A proper CAC COA lists Al₂O₃, Fe₂O₃, SiO₂, CaO, MgO, setting time, and strengths. If a supplier can't produce this per lot, move on. We send ours with every shipment and keep retained samples on both sides.
Third, packaging and moisture. CAC hydrates if it gets wet - ruined powder sets in the bag. 25 kg valve bags with inner liner, or 1,000 kg bulk bags, palletized and shrink-wrapped for sea freight. Ask for moisture protection explicitly; it costs little and saves a whole lot.
Fourth, trial before volume. One 1-ton lot tells you setting time, strength gain, and color consistency in your own mix - cheap insurance before a 50-ton order. Any CAC mill that hesitates to supply a trial lot is telling you something.
Ordering: MOQ, Price & Lead Time
MOQ is 5 tons per grade, mixed grades welcome in one container. Indicative pricing, FOB Qingdao: CA-50 runs
We keep 300+ tons of CA-50 and CA-70 in Qingdao - the grades most castable plants order monthly. If you need a trial lot before committing, 1-ton samples ship within a week.
Send us your mix design target or the castable grade you're producing, and we'll confirm the CAC grade, COA template, and packing within 24 hours. Our engineers have formulated castables for 15 years - we can check your recipe for free before you order. Our product page carries the quick spec sheet if you just need the numbers.
Quality Control & What Ships With Every Lot
ISO 9001:2015 (Certificate No. 16202001575Q) covers the plant. Testing follows GB/T 201-2015 for aluminate cements. Every calcium aluminate cement lot ships with a COA: Al₂O₃, Fe₂O₃, SiO₂, CaO, MgO, setting time, 1-day and 3-day compressive strengths, and fineness. We test every batch, not every shipment.
Retained samples are kept for every lot on both sides. If a dispute comes up - and in ten years of CAC supply, we've had one - we test both samples together and settle on numbers.
Bottom line: calcium aluminate cement is the binder that decides how well your castable survives first heat - grade it to the service temperature, verify the COA, and buy from a mill that tests every batch. Send us your mix, and we'll confirm the right grade within 24 hours.
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