Hey everyone, it’s Jake here from the polyaluminium chloride team, and today I’m answering one of the most common questions I get from new customers hitting our site or sliding into DMs: What’s the actual chemical formula for White Polyaluminium Chloride (yes, the white, powdery version of PAC we supply)? White Polyaluminium Chloride
First off, let’s cut through the jargon because I know a lot of you don’t care about textbook-level formulas—you care about what this stuff does, especially if you’re a water treatment plant manager, a papermaker, or someone who needs a reliable coagulant for their process. I’ll keep this real, no fancy chemistry degree required.
Let’s start with the basics. Regular polyaluminium chloride (PAC) is that yellowish or tan powder you might see at a hardware store for small water tanks. But our white PAC? That’s the high-purity grade, right? No heavy metals, no leftover byproducts from cheaper manufacturing, so that’s why its formula’s a bit different and matters more for sensitive applications like drinking water treatment or cosmetics-related processes.
So what’s the formula? It’s not a single, neat number like H2O, I’ll warn you. PAC is a polymeric compound, meaning it’s made of repeating groups of molecules, not just one static formula. For white PAC specifically, the general chemical formula is [Al₂(OH)ₙCl₆₋ₙ]ₘ. Wait, let me translate that for non-chem folks: Al is aluminium, OH is hydroxide, Cl is chloride, n is a number between like 1 and 5, and m is the degree of polymerization—how many of those groups link together.
Here’s the thing: the n number is super important for white PAC. For the cheaper yellow PAC, n might be lower—like 1 or 2, which means more chloride, which can leave residue and make it less effective for clean water. Our white PAC has an n of 2 to 5, mostly around 3, right? That’s the sweet spot because it means more hydroxide groups, which are what make it a coagulant. When you add it to water, those aluminium hydroxide clusters grab onto tiny dirt particles, algae, even microplastics, and clump them up so they sink to the bottom. No weird leftover chemicals either, which is why we target that n range.
And m? For white PAC, m is usually 10 to 20 for our standard grade, and up to 50 for our ultra-high-purity version. The higher m is, the bigger the polymer chains, the faster it works. You add less of our white PAC than you would of the yellow stuff for the same result—saves you money in the long run, that’s a win-win.
Wait, why is it called “white” anyway? The manufacturing process. Regular PAC is made using raw materials like bauxite, which has iron and other impurities that turn it yellow. White PAC uses aluminium hydroxide or high-grade aluminium metal, processed at a lower temperature with strict pH controls. No iron, no heavy metals like lead or arsenic, so the powder’s snow-white. That purity directly affects its formula—those impurities would mess up the n and m values, so our manufacturing keeps those numbers consistent every single batch, no surprises.
Let’s talk about why the formula matters for you, not just us chem nerds. If you’re treating drinking water, you can’t have excess chloride or heavy metals ending up in the tap. Our white PAC’s formula ensures that when it hydrolyzes (that’s just a fancy word for mixing with water), it forms aluminium hydroxide flocs without releasing harmful byproducts. For papermakers, white PAC improves paper strength and retention of fine fibers, and since it’s white, it doesn’t stain the paper—big difference from the yellow PAC that might leave discoloration. And for industrial wastewater, our consistent formula means you can dose it exactly as calculated, no need to adjust every week because the batch is off.
I get it, a lot of suppliers will just throw a formula at you and not explain what it actually means for your business. We’ve had customers switch to our white PAC because they were having issues with their coagulant leaving a white residue in their process, or their water quality tests failing because of excess chloride. When we send them our COA (Certificate of Analysis), they can see the n value is 3.2, m is 18, and heavy metal levels are all below EPA limits— that’s the formula in action, not just a number on a page.
Wait, let’s clear up a common myth: some people think white PAC is AlCl3, but no—AlCl3 is aluminium chloride, a totally different compound. It’s a single molecule, not a polymer, so it doesn’t form flocs as well. You’d have to use way more, and it leaves more chloride. Our formula’s polymeric structure is the whole reason it works so efficiently. Yellow PAC is closer to AlCl3 with impurities, but white PAC is all about those hydroxide-bridged aluminium polymers.
Another thing: the formula can vary a tiny bit depending on the grade, but we standardize it across all our production runs. We test every batch with NMR (Nuclear Magnetic Resonance) spectroscopy to confirm the n and m values, so our customers don’t have to worry about inconsistent results. If you’re comparing suppliers, ask for the n value—if they don’t list it, that’s a red flag. Any quality white PAC should have an n between 2 and 5.
Let’s be real, I’m not here to sell you something you don’t need, but if you’ve ever dealt with water treatment downtime, paper defects, or product contamination from low-grade chemicals, you know how important consistency is. Our white PAC’s formula isn’t just a random set of numbers—it’s the result of years of tweaking our manufacturing process to get that perfect balance of aluminium, hydroxide, and chloride that works for the most demanding applications.
So, to wrap this up: White Polyaluminium Chloride isn’t a single chemical compound with a fixed formula. It’s a polymeric coagulant with the general formula [Al₂(OH)ₙCl₆₋ₙ]ₘ, where n is typically 2–5 (for high purity) and m is 10–50, depending on the grade. That purity and consistent structure is what makes white PAC the go-to for drinking water, high-end papermaking, and sensitive industrial processes.
If you’re currently using a yellow PAC and tired of the extra handling, residual issues, or inconsistent results, or if you need a reliable coagulant for a project that requires top-tier purity, hit us up to talk procurement. We can send over a sample, share actual COAs, or walk you through how much you’ll need for your specific application—no pressure, just real answers from a supplier who’s been in this game long enough to know what matters.
Drinking Grade Polyaluminium Chloride References
- Vandeven, T. H. Polyaluminium Chloride: Production, Structure, and Applications. Water Science and Technology, 2000, Vol. 41, No. 10, pp. 1–8.
- American Water Works Association. Chemical Aspects of Coagulation and Flocculation in Drinking Water Treatment. AWWA Manual M37, 2013.
- Li, X.; Wang, Z. High-Purity Polyaluminium Chloride: Synthesis and Performance for Potable Water Treatment. Journal of Environmental Chemical Engineering, 2018, Vol. 6, No. 3, pp. 3892–3899.
Shandong Ecolink Technology Co., Ltd.
Shandong Ecolink Technology Co., Ltd. is one of the most reliable white polyaluminium chloride manufacturers and suppliers in China. We warmly welcome you to wholesale bulk high quality white polyaluminium chloride from our factory. If you have any enquiry about cooperation, please feel free to email us.
Address: No. 8, Xiaying Chemical Industry Park, Aobu Road, Xiaying Town, Changyi City, Weifang City, Shandong Province，China
E-mail: sale02@ecolink-environment.com
WebSite: https://www.ecolink-environment.com/
