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production processes of iron oxide yellow

Iron oxide yellow is a transparent powder yellow pigment. The relative density was 3.5. The chemical properties are stable. The particle size is 0.01-0.02 μ M. It has large specific surface area (about 10 times of ordinary iron oxide), strong ultraviolet absorption, light resistance, atmospheric resistance and other good properties. The film is transparent and has good properties. How to make iron oxide yellow?

 

Method : ferrous sulfate oxidation method: sulfuric acid reacts with iron filings to form ferrous sulfate. Sodium hydroxide is added and air is used to oxidize to prepare crystal nucleus. Ferrous sulfate and iron chips are added into the suspension of crystal nucleus, heated and blown into air for oxidation. Ferric oxide yellow is prepared by pressure filtration, rinsing, drying and grinding.

 

Fe+H2SO4→FeSO4+H2↑

Fe+H2SO4→FeSO4+H2↑

FeSO4+2NaOH→Fe(OH)2+Na2SO4

FeSO4+2NaOH→Fe(OH)2+Na2SO4

4Fe(OH)2+O2→4FeOOH+2H2O

4Fe(OH)2+O2→4FeOOH+2H2O

H2SO4+Fe+7H2O→FeSO4·7H2O+H2↑

H2SO4+Fe+7H2O→FeSO4·7H2O+H2↑

 

FeSO4·7H2O+O2→2Fe2O3·H2O↓+4H2SO4+2H2O

FeSO4 · 7H2O + O2 → 2fe2o3 · H2O ↓ + 4h2so4 + 2H2O reaction conditions: add 74g iron chips into 1000ml 15% sulfuric acid until iron chips disappear, and form ferrous sulfate with concentration of about 200g / L. Sufficient 30% sodium hydroxide is added into the ferrous sulfate solution, and 40% of the total iron is converted into ferrous hydroxide [Fe (OH) 2] by continuous stirring, and the iron is oxidized to Fe to form crystal nucleus at 30 ~ 35 ℃. Then 90 g / L iron filings were added to the mixture to form 7 g / L crystal nucleus and 40 g / L ferrous sulfate, and then heated to 85 ℃ for air oxidation at a speed of 600 L / h for 64 h, and then filtered, washed, dried and crushed to obtain hydrous ferric oxide yellow.


Post time: Jul-29-2020