Products Description of Aluminum hydroxide CAS#21645-51-2
This industrial-grade aluminum hydroxide boasts a minimum purity of 99%. It occurs as an odorless white crystalline powder with typical amphoteric chemical characteristics. Its melting point is 300℃ with decomposition upon heating, and the boiling point reaches 2980℃. At 25℃, its vapor pressure stays below 0.1 hPa, while the relative density is 2.42 measured at 20℃. In terms of solubility, it is slightly soluble in water, readily soluble in acids and strong alkalis, and insoluble in ethanol. The material maintains good stability under regular storage conditions, though it cannot be mixed or stored together with strong bases.
Parameters
Melting point | 300℃ |
Boiling point | 2980℃[at 101 325 Pa] |
bulk density | ~90g/100 mL |
density | 2.42 g/cm3 at 20 °C |
vapor pressure | <0.1 hPa (20 °C) |
refractive index | Average refractive index: 1.57-1.59 |
storage temp. | Store at +5°C to +30°C. |
solubility | 0.0015g/l |
form | colloidal suspension |
color | White |
Specific Gravity | 2.42 |
Odor | Odorless |
PH | 8-9 (100g/l, H2O, 20℃)(slurry) |
PH Range | >7 |
Water Solubility | insoluble |
Crystal Structure | Monoclinic |
Merck | 14,342 |
Solubility Product Constant (Ksp) | pKsp: 32.89 |
Dielectric constant | 2.2（Ambient） |
Exposure limits | ACGIH: TWA 1 mg/m3 |
Stability: | Stable. Incompatible with strong bases. |
LogP | -1.380 (est) |
CAS DataBase Reference | 21645-51-2(CAS DataBase Reference) |
EPA Substance Registry System | Aluminum hydroxide (21645-51-2) |
Safety Information
Hazard Codes | Xi |
Risk Statements | 36 |
Safety Statements | 26-36 |
WGK Germany | - |
RTECS | BD0940000 |
TSCA | Yes |
HS Code | 28183000 |
Hazardous Substances Data | 21645-51-2(Hazardous Substances Data) |
Toxicity | TDLo oral in child: 79gm/kg/2Y-I |
Aluminum hydroxide CAS#21645-51-2
Product Application
Aluminum hydroxide has many advantages including large-scale production, adequate raw materials, high product purity and good solubility in acid. Therefore, aluminum hydroxide can be used as an important raw material for the preparation of aluminum salts, such as barium aluminate, aluminum sulfate and so on.
Basic Information
Product Name: Aluminum Hydroxide
CAS No.: 21645-51-2
Molecular Formula: Al(OH)₃
Molecular Weight: 78.00
Appearance: White amorphous powder
Purity: ≥99.0% (Customizable grades available)
Moisture: ≤0.3%
Whiteness: ≥94%
Particle Size: Custom mesh available (100mesh, 200mesh, 325mesh, etc.)
Density: 2.42 g/cm³
Solubility: Insoluble in water and ethanol, soluble in strong acid and strong alkali
Quality Standard
Each batch is accompanied by COA test report covering appearance, purity, moisture, particle size and impurity items. TDS and MSDS can be provided upon request before shipment.
Application Scenarios by Industry
Raw Material for Aluminum Salt Synthesis
As mentioned, it is the key feedstock to produce multiple aluminum salts including aluminum sulfate, barium aluminate, polyaluminum chloride and sodium aluminate. Widely adopted in fine chemical plants for inorganic salt synthesis.
Flame Retardant & Filler for Composite Materials
It is a halogen-free inorganic flame retardant and smoke suppressant for plastics, rubber, silicone and unsaturated polyester resins. When heated, it releases water vapor to absorb heat and suppress flame propagation. Commonly used in cable materials, FRP panels, electronic plastic parts and architectural insulation boards.
Water Treatment Industry
Used as raw material for preparing polyaluminum chloride (PAC), a widely used flocculant for drinking water and wastewater treatment. It helps to precipitate suspended solids and remove heavy metal contaminants in water.
Ceramic & Glass Industry
Serves as alumina source for ceramic glaze, high-grade glass and enamel products. It improves thermal stability, mechanical strength and surface smoothness of ceramic and glass finished goods.
Filler for Coatings & Adhesives
Used as functional filler in architectural coatings, putty and adhesives. It enhances coating hardness, reduces cost and endows certain fire-resistant performance.
Pharmaceutical & Antacid Field
Pharmaceutical grade aluminum hydroxide is used as antacid raw material to neutralize excess gastric acid in stomach medications.
Packaging & Transportation
Packaging Options
Standard package: 25kg kraft paper bag with PE inner liner
Bulk packaging: 500kg / 1000kg big bag for large orders
Package marking: Product name, CAS number, batch number, net weight, hazard labels printed on each bag
Transport Requirements
This product is non-dangerous goods for international transportation.
Keep packages sealed and protected from moisture and rain during transit
Avoid mixing with strong acid and strong alkali chemicals
Prevent heavy extrusion and bag breakage
Storage Condition
Store in cool, dry and ventilated warehouse. Keep away from moisture, acids and alkalis. Keep packages tightly sealed. Shelf life: 12 months under proper storage.
Delivery Schedule
In stock goods: Shipment within 2–3 working days after receiving payment
New production batch: Production & delivery within 7–10 working days
Large bulk orders: Lead time can be negotiated separately
We support EXW, FOB, CIF, FCA and other trade terms as customer required.
After-sales Service
Document service: Supply COA, MSDS, TDS, commercial invoice, packing list and other customs clearance documents.
Quality handling: If quality issues are confirmed within agreed inspection period, we will actively communicate and provide solutions.
Technical consultation: Our chemical team offers guidance on product selection, dosage and safe operation.
Cargo tracking: Update cargo status after shipment and inform customers of logistics progress.
Import consultation: Provide advice on destination country import customs requirements.
Customer Cases
Case 1: Inorganic Salt Factory in South Asia
Long-term purchase of aluminum hydroxide to produce aluminum sulfate and polyaluminum chloride. Stable particle size and low impurity greatly improve the finished salt quality.
Case 2: Cable Material Manufacturer in Middle East
Used as halogen-free flame retardant filler for cable sheath. It meets local fire safety standards and reduces smoke emission during combustion.
Case 3: Ceramic glaze factory in Southeast Asia
Adopted as alumina source for ceramic glaze, improving the gloss and thermal shock resistance of ceramic products.
FAQ
Q1: Can I get samples for lab test?
A: Yes, small quantity samples can be provided for testing. Sample freight can be negotiated.
Q2: Can particle size and purity be customized?
A: Yes. We can produce different mesh sizes and grades according to your technical requirement. MOQ applies for customized products.
Q3: What documents can you provide for customs clearance?
A: Commercial invoice, packing list, COA, MSDS and other supporting documents on request.
Q4: What is the MOQ?
A: MOQ is one 25kg bag. Better unit price for bulk orders.
Q5: Is aluminum hydroxide hazardous during handling?
A: It is non-hazardous chemical. Avoid long-term dust inhalation. Wear dust mask and gloves when handling. Refer to MSDS for full safety instructions.
