Sodium dichromate dihydrate
Sodium dichromate dihydrate
CAS: 7789-12-0
Molecular Formula: Cr2H5NaO8
Sodium dichromate dihydrate - Names and Identifiers
Sodium dichromate dihydrate - Physico-chemical Properties
| Molecular Formula | Cr2H5NaO8 |
| Molar Mass | 260.01 |
| Density | 2,348 g/cm3 |
| Melting Point | 91°C(lit.) |
| Boling Point | 400°C |
| Water Solubility | 730 g/L (20 ºC) |
| Solubility | Methanol (Slightly, Sonicated) |
| Vapor Density | 10 (vs air) |
| Appearance | Solid |
| Specific Gravity | 2.348 |
| Color | Red-orange |
| Odor | Odorless |
| Merck | 14,8609 |
| Storage Condition | Store at +5°C to +30°C. |
| Sensitive | Hygroscopic |
| Physical and Chemical Properties | Orange-red monoclinic pyramidal or fine needle-like crystals. Easily soluble in water, its aqueous solution is acidic and insoluble in alcohol. |
Sodium dichromate dihydrate - Risk and Safety
| Risk Codes | R45 - May cause cancer R46 - May cause heritable genetic damage R60 - May impair fertility R61 - May cause harm to the unborn child R8 - Contact with combustible material may cause fire R21 - Harmful in contact with skin R25 - Toxic if swallowed R26 - Very Toxic by inhalation R34 - Causes burns R42/43 - May cause sensitization by inhalation and skin contact. R48/23 - R50/53 - Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. |
| Safety Description | S53 - Avoid exposure - obtain special instructions before use. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S60 - This material and its container must be disposed of as hazardous waste. S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
| UN IDs | UN 3086 6.1/PG 1 |
| WGK Germany | 3 |
| RTECS | HX7750000 |
| TSCA | Yes |
| HS Code | 28413000 |
| Hazard Class | 5.1 |
| Packing Group | III |
Sodium dichromate dihydrate - References
| pH indicator color change ph range | 3.5-4.0 |
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| solubility in water (g/100ml) | dissolution grams per 100ml of water at different temperatures (℃): 163g/0 ℃;172g/10 ℃;183g/20 ℃;198g/30 ℃;215g/40 ℃ 269g/60 ℃;376g/80 ℃;405g/90 ℃;415g/100 ℃ |
| use | used in the manufacture of chromic anhydride and chromium salt, etc., used as tanning agent, mordant, also used in passivation treatment after galvanizing and metal surface treatment, synthetic dyes, camphor and spices, etc. used as analytical reagents, oxidants, preservatives, and also used in organic synthesis mainly used in the manufacture of chromic yellow pigments, chromic anhydride and other chromium salts. It is also used for metal impregnation and etching, electroplating, mordant dyeing of wool fabrics, tanning, etc. Used in the manufacture of chromic anhydride, potassium dichromate, basic chromium sulfate, chrome yellow, lignosulfonate, etc. The tanning industry is used as a tanning agent. In the printing and dyeing industry, it is used as an oxidant when dyeing with aniline dyes, as a post-treatment agent when dyeing with sulfide vat dyes, and as a mordant when dyeing with acid mordant dyes. The pharmaceutical industry is used to produce amine phenyl sulfone, benzocaine, folic acid, Rifonol, etc. Electroplating industry is used for passivation treatment after galvanizing to increase brightness. It is also used for metal surface treatment. Used in the production of alkaline lake blue dyes, saccharin, synthetic camphor, synthetic fibers, synthetic spices. Used in the manufacture of chromium salts, pigments, dyes, spices, medicine, and also used in tanning, electroplating and other industries The manufacture of tanning, dyes, pigments and other chromium salts |
| production method | the production of sodium dichromate mainly includes the production of sodium chromate and the conversion of sodium chromate into sodium dichromate. At present, sulfuric acid is mainly used in the industrial conversion of sodium chromate. Electrolysis is being developed. The chromite is crushed to 200 mesh by sulfuric acid method, mixed with soda ash (the general dosage is 90% ~ 93% of the theoretical amount), self-marble powder, limestone powder and slag according to a certain ratio, and then sent to the rotary kiln, and oxidized and roasted at 1100~1150 ℃ for 1.5~2 h to convert chromium trioxide into sodium chromate. After the sintered clinker is cooled and crushed, a dilute solution and water are used for multi-stage countercurrent leaching and suction filtration in a leach to obtain a sodium chromate solution of 35~40 Bé. Ph was adjusted to 7~8 to hydrolyze sodium aluminate into aluminum hydroxide precipitate, which was removed after filtration. After the neutral filtrate evaporates to 48 Bé, it is acidified by adding concentrated sulfuric acid to convert sodium chromate into sodium dichromate. After two evaporations, the sodium sulfate is completely removed, and then clarified to remove all insoluble impurities. The clarified liquid is cooled to 30~40 ℃ for crystallization, and the finished product of sodium dichromate is prepared by centrifugal separation. Mother liquor is returned to neutralization or used to make other chromium salt products. Its 4(FeO Cr2O3)+8Na2CO3+7O2 → 8Na2CrO4+2Fe2O3+8CO2 ↑ 2Na2CrO4 + H2SO4 → Na2Cr2O7 + Na2SO4 + H2O pulverizes chromite to 200 mesh, mixes it with soda ash (the dosage is 90% ~ 93% of the theoretical amount), dolomite powder, limestone powder and slag, and sends it to a rotary kiln, and oxidizes and roasts at 1,000~1,150 ℃ for 1.5~2 hours to convert chromium trioxide into sodium chromate. After the burnt clinker is cooled and crushed, it is leached with dilute solution and water in multiple stages in a leach. 35~40 ° Bé sodium chromate solution was obtained by suction filtration. The pH value is adjusted to 7-8 to hydrolyze sodium aluminate into aluminum hydroxide precipitate, which is removed after filtration. After the neutral filtrate evaporates to 48 ° Bé, it is acidified by adding concentrated sulfuric acid to convert sodium chromate into sodium dichromate. After two evaporations, the sodium sulfate is completely removed, and then clarified to remove all insoluble impurities. The clarified liquid is cooled to 30~40 ℃ for crystallization, and the finished product of sodium dichromate is prepared by centrifugal separation. Mother liquor is returned to neutralization or used to make other chromium salt products. Its |
Last Update：2024-04-10 22:29:15
