Which oxalic acid grade and form to order in Oman, how much to mix for marble, wood and rust stains, and how to handle and store it safely, with delivery from Barka.
Dull marble, grey teak and rust streaks on a villa wall can all be treated with one chemical: oxalic acid. As an oxalic acid supplier in Oman, we list oxalic acid powder in 25 kg packs and oxalic acid liquid in 210 L packs, supplied from Barka Industrial Area. Below you will find which grade and form to order, how much to mix for each job, and how to handle and store it safely in Gulf heat.
Oxalic acid supplier Oman: what we offer from Barka
We list three oxalic acid lines. Oxalic Acid powder, part number RXSOL-19-1303-025, is fine colourless crystalline powder in 25 kg packs. Oxalic Acid PWD, part number RXSOL-19-1303-050, is the same crystalline product under its own part number; ask us for its current pack size. Oxalic Acid Liquid 210 Ltrs, part number RXSOL-19-1410-020, is a ready-made solution that its safety data sheet lists at 45-60% oxalic acid.
Choose the powder if you run a marble or wood workshop, or if you want to set the strength yourself for each job. Choose the liquid if your maintenance crew wants to start work without weighing and dissolving crystals on site. In both cases you still dilute to the working strength for the surface you are cleaning.
What oxalic acid is: grade, purity and key specs
Oxalic acid (ethanedioic acid) is a dicarboxylic organic acid, formula C2H2O4. It is usually supplied as the dihydrate H2C2O4·2H2O, molecular weight about 126.07. CAS 144-62-7 is the anhydrous form and CAS 6153-56-6 is the dihydrate. It acts as a reducing agent and chelates iron, which is why it lifts rust: on iron oxide it forms water-soluble iron oxalate (Fe2O3 + 3H2C2O4 → Fe2(C2O4)3 + 3H2O).
Our powder specification is oxalic acid content min 99.00% by mass. Many oxalic acid technical grade sheets quote 99.6% purity, which is a typical figure from a certificate of analysis. Manufacturers often grade the product as premium grade min 99.6%, first grade 99.4% and qualified grade 99.0%. A typical figure describes one batch, while a minimum is the floor every batch must meet, so ask us for the SDS with your order and check the specification against your process.
| Item | Detail |
|---|---|
| Part numbers | RXSOL-19-1303-025 (powder), RXSOL-19-1303-050 (powder), RXSOL-19-1410-020 (liquid) |
| Chemical name | Oxalic acid (ethanedioic acid), dihydrate H2C2O4·2H2O, Mol Wt. 126 |
| CAS | 144-62-7 (anhydrous), 6153-56-6 (dihydrate), EINECS 205-634-3 |
| Appearance | Fine colourless and odourless prismatic crystals, powder form |
| Technical specs (powder) | Oxalic acid content min 99.00%; sulphated ash max 0.15%; chloride (as Cl) max 0.005%; sulphates (as SO4) max 0.10%; iron (as Fe) max 0.05% |
| Typical physical data | Melting point about 101.5 °C, decomposes at about 157 °C, solubility in water about 14 g/100 mL, pH about 1.0 for a 13% solution, not flammable |
| Application | Marble polishing, wood bleaching, rust and iron stain removal, metal and equipment cleaning, boat and deck cleaning, mordant in dyeing |
| Typical dilution | 1 kg crystals in 6 L warm water for iron stains; other ratios in the sections below |
| Packing | Powder 25 kg (RXSOL-19-1303-025); liquid 210 L (RXSOL-19-1410-020) |
| Transport | UN 3261, Corrosive solid, acidic, organic, n.o.s. (oxalic acid), Class 8, Packing Group III |
| MSDS | On request with every order |
Oxalic acid for marble polishing, and why not on granite
Marble polishing powder works because oxalic acid reacts with the calcium carbonate in the stone under water and friction (CaCO3 + H2C2O4 → CaC2O4 + H2O + CO2). The reaction leaves a harder, more reflective calcium oxalate layer on the surface. Keep the slurry wet and the machine moving so the reaction stays even.
This only works on calcium-based stone: marble, limestone and travertine. Oxalic acid has no effect on granite, quartzite or engineered quartz. In Muscat villas, hotel lobbies and mosques you often find marble floors next to granite steps or quartz counters, so check which stone you are on before your crew starts.
Strong "hot" powders contain more oxalic acid and act fast, but they can cause an orange peel texture on soft marble. Gentler "cold" powders suit soft stone. Etch marks from spilled juice or cleaners are not stains: light etching is honed out first, from about 400 grit up through 1,500 and 3,000, and then polished. We do not publish a fixed powder-to-water ratio for polishing, so try your mix on an offcut or a hidden corner first.
Oxalic acid as a wood bleach for teak, oak and tannin stains
Oxalic acid wood bleach removes black water stains, tannin stains and the grey cast that timber takes on outdoors. It works best on high-tannin woods such as oak, teak, walnut and mahogany, which covers most of the furniture and doors restored in Oman.
For stains on unfinished wood, a typical mix is 1/4 lb (about 115 g) of crystals per gallon of warm water. Paint it on, leave about 15 minutes, rinse with cold water and repeat if needed. A stronger mix of about 2 cups per gallon of hot water is also used for wood. Spread the solution evenly to avoid patchy bleaching, and rinse until no white residue is left.
Let the timber dry completely before you sand or refinish. The surface must be clean and completely dry (not just surface dry), because retained subsurface moisture can cause finish adhesion failure. Oxalic acid is also used on timber, GRP and steel craft to remove rust and waterline stains, and to clean timber decks. For vertical surfaces, mix oxalic acid with wallpaper paste so it clings, then wash it off with water.
Removing rust and iron stains from concrete, paving and metal
Orange stains from bore-well and irrigation water on paving, boundary walls and villa facades are iron deposits, and oxalic acid is a reliable rust stain remover for them. Pre-clean the surface first. For iron stains, dissolve 1 kg of crystals in 6 L of warm water, scrub the stained area with a stiff-bristle brush, then rinse thoroughly with water. A lighter mix of about 1 cup of crystals per gallon (≈3.8 L) of warm water is also used on concrete, paving and walls.
For rusty metal parts, a typical soak is 1 part acid to 10 parts water, for up to a day. Dilute solutions can be used on galvanised and stainless steel, but avoid long exposure on metals. Strong solutions can damage enamelled cast iron, so use weaker repeated applications there instead.
Safety, rinsing and storage in Gulf heat
Oxalic acid dihydrate carries the signal word DANGER: H302 harmful if swallowed, H312 harmful in contact with skin, H318 causes serious eye damage. The exposure limit for the anhydrous form is TWA 1 mg/m³, STEL 2 mg/m³. Wear safety goggles or a face shield, protective gloves and a lab coat or apron, and use a respirator if dust is generated while you weigh or pour powder.
First aid: for eyes, flush with water for at least 15 minutes and get medical attention. For skin, wash with soap and water. If swallowed, give 1 or 2 glasses of water and call for medical assistance immediately.
After every job, rinse the surface thoroughly with clean water until no white residue remains. Oxalic acid is readily biodegradable but toxic to aquatic life at higher levels (fish LC50 about 34 mg/L/96 h), so do not let concentrated runoff into drains, wadis or the sea.
Store bags in a cool, dry, well-ventilated area, away from heat, direct sun and moisture, and reseal opened bags. A summer warehouse in Barka or Sohar is hot and humid, so keep stock off the floor and away from the roller door. Keep oxalic acid away from alkalis, chlorites, hypochlorites such as chlorine bleach, oxidising agents and silver compounds.
Where to buy oxalic acid in Muscat and across Oman
Muscat Chemical (Muscat and Barka for Business Trading) supplies oxalic acid from Barka Industrial Area, Sultanate of Oman. Call +968 77333599, message us on WhatsApp at +968 77333599 or email muscatchem@gmail.com. Tell us your site location when you enquire and we will confirm supply arrangements.
The same powder is also listed on our sister site as oxalic acid on the Sohar site. Buyers in Dhofar can see oxalic acid powder for Salalah on our southern site. If you also need cleaners, rust removers or polishing supplies in the same enquiry, browse our full product range.
Send us the product, the quantity and your location through the quote request form, and ask for the SDS at the same time. To request a quote now, message us on WhatsApp at +968 77333599.
Frequently asked questions
Where can I buy oxalic acid in Oman?
Muscat Chemical supplies oxalic acid powder and oxalic acid liquid from Barka Industrial Area. Call or WhatsApp +968 77333599 or email muscatchem@gmail.com with your product, quantity and site location for a quote.
How much oxalic acid do I mix with water to remove rust stains?
For iron stains, dissolve 1 kg of crystals in 6 L of warm water, scrub with a stiff-bristle brush and rinse thoroughly. A lighter mix of about 1 cup of crystals per gallon (about 3.8 L) of warm water is also used on concrete and paving. For soaking rusty metal parts, a typical ratio is 1 part acid to 10 parts water for up to a day.
Does oxalic acid work on granite or quartz?
No. Oxalic acid polishing works only on calcium-based stone such as marble, limestone and travertine. It has no effect on granite, quartzite or engineered quartz, so check the stone before you start.
What is the difference between oxalic acid powder and oxalic acid liquid?
The powder (RXSOL-19-1303-025, min 99.00% oxalic acid, 25 kg) lets you set the strength for each job and suits marble and wood workshops. The liquid (RXSOL-19-1410-020, 210 L, 45-60% oxalic acid per its SDS) saves dissolving crystals on site and suits maintenance crews. Both are diluted to working strength before use.
What purity of oxalic acid do I need: 99.6% technical or another grade?
Technical grade is commonly sold as 99.6% typical, which is the measured result of a batch. Our powder specification is min 99.00%, the floor every batch must meet. For stain removal, polishing and wood bleaching technical grade is the usual choice; ask us for the SDS and check the specification against your process.