Aluminum citrate comes from combining aluminum, a common lightweight metal, with citric acid, a weak organic acid found naturally in citrus fruits. The result is a compound used in a wide range of industries, from water treatment to pharmaceuticals and specialty chemicals. People tend to notice aluminum citrate as either a white or off-white solid, and the way it shows up—from dense powder to shiny flakes—depends on the production method. Its chemical formula is commonly written as AlC6H5O7, and that formula points to one aluminum atom tangled up with a citrate ion, which is itself made from the sugars and acids you’ve probably heard of in chemistry labs.
The structure of aluminum citrate tells you a lot about how it acts. Its molecules organize in a somewhat complex network, the aluminum ions anchored by citrate groups. As a solid, it’s often found in powder or crystal form, with a dry, sometimes slightly gritty texture. Chemically, it takes on a molecular weight of about 258.11 g/mol, sliding into formulas and processes where that precise number matters. The density tends to hover around 1.74 g/cm³, noticeably less than heavier metal salts, so it blends smoothly in both aqueous solutions and solid mixtures. Drop some in water, and it dissolves slowly but thoroughly, bringing out the distinctive acidic taste and faint metallic tang—students in chemistry classes will sometimes remember this from lab work.
Companies produce aluminum citrate in several forms to match up with different applications. The powder type spreads evenly and mixes easily with other solids, making it the go-to choice for blending into powders or compressed tablets. Flake versions feel coarse, like fish food, and pour easily into industrial mixers when you need to regulate how fast it dissolves. The crystal type looks a bit like table salt, and technicians choose it for scientific work where purity stands out. Liquid or solution forms contain aluminum citrate dissolved in water, and those solutions become handy for dosing in water treatment plants, because they reduce guesswork in measurement and improve consistency on a large scale. Across all forms, shelf life holds steady at about two years if you keep it in a tightly closed, dry container.
Zooming in on the molecular side, aluminum citrate breaks down into its core ions in water. This solubility comes from the layered crystalline structure; bonds snap apart as molecules float away into solution. Purity levels are usually rated above 98%, and most suppliers ship out product that meets tight benchmarks for heavy metals, moisture, color, and particle size. Users spot the HS Code 2918.15.0090 on shipping invoices, which groups it under citric acid salts for international trade. Specific gravity test results often land just under water, which means the dissolved liquid feels lighter in the hand compared to metal-heavy alternatives. In my own experience, handling the powder takes some care—fine grains can float into the air, sticking to hands and nearby surfaces as an itchy residue, so keeping the workspace clean matters.
Most aluminum citrate starts its life from aluminum hydroxide and citric acid, both common raw materials in the chemical industry. These come together in a controlled reaction, followed by careful filtration and drying. Factories often scale up from small lab batches to drums of solid powder, big bags of flakes, and even liters of concentrated solution. End uses stretch from antiperspirants, where astringency plays a big part, to specialty laboratory reagents, and the compound even sneaks into some water purification processes as a flocculant to remove unwanted ions. The most careful manufacturers track every batch by lot number, documenting pH, water content, and any trace contaminants to back up claims of quality.
Getting a clear picture of safety matters for aluminum citrate. Generally, toxicity sits at a manageable level, but dust can irritate airways and the eyes, especially if used in a cramped or poorly ventilated room. Long-term inhalation exposure remains a concern for those who handle large quantities every day. Skin contact doesn’t lead to major issues in most people, though repeated exposure can dry out or redden sensitive hands. It’s not considered flammable, but mixing with some strong oxidizers deserves caution. I’ve always kept basic safety gear nearby—gloves, dust mask, lab goggles—after seeing a coworker receive an unexpected rash while pouring powder. Hazard sheets recommend storing away from acids such as hydrochloric acid, since mixing can trigger gas release.
Disposing of excess aluminum citrate shouldn't mean careless dumping. As a metal-organic salt, it can upset aquatic balance if released in high concentration, due to aluminum ions interfering with fish gills and plant roots. Safe practice means neutralizing small quantities with household base, diluting thoroughly, and sending any larger volume to a licensed waste handler. Most local regulations set clear criteria for heavy metal solutions, which anyone working with industrial quantities gets to know fast. Over the years, I’ve seen responsible teams keep wastewater records and log disposal, because missing a step here could end up with regulatory fines or worse.
Looking at solutions, better packaging—especially resealable, moisture-proof drums—helps slow down spoilage. Moving to enclosed conveyor systems cuts down on dust released in factories, reducing health risks for workers. Clearer labeling about water content and particle size benefits customers on the receiving end, who need to match product to process with fewer surprises. Teaching proper spill cleanup actually sticks in workers’ memories if the training uses real-life stories instead of just rules on posters.
