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Production Method Of Chromic Potassium Sulfate
- May 25, 2017 -

Chromic Potassium Sulfate for the manufacture of metal rust inhibitors and chromates. Used as an oxidizing agent, printing and dyeing mordant. For ink, paint, enamel, metal corrosion and so on.

Have an oxidative effect. For tanning, medicine, and used as mordant and analytical reagents. Can be used for the role of silver nitrate titration of chlorine chloride indicator. Indicator formula: 10g Chromic Potassium Sulfate dissolved in 100mL water, titration with AgNO3 to magenta precipitation, standing overnight. The titration end point changes from red to orange

In the aqueous solution, Chromic Potassium Sulfate dissociates chromate ions (CrO4, yellow), forms a balance with another dimerized dichromate ion (Cr2O7, red), and acid addition causes the reaction to equilibrate to the dichromate ion , So that the solution was orange-red: 2 CrO4 +2 H ⇌ Cr2O7 + H2O

Chromic Potassium Sulfate in the solution to provide chromate ions, with Ba, Pb and Ag to form a precipitate:

Ba + CrO4 → BaCrO4 ↓ (yellow)

Pb + CrO4 → PbCrO4 ↓ (yellow)

2Ag + CrO4 → Ag2CrO4 ↓ (brick red)

Which BaCrO4 commonly known as lemon yellow, PbCrO4 commonly known as chrome yellow, they can be used as yellow pigment

Chromic Potassium Sulfate can react with hydrogen peroxide under alkaline conditions to form potassium peroxochlorinate:

2 K2CrO4 + 7 H2O2 + 2 KOH → 2 K3CrO8 + 8 H2O

But potassium peracetic acid is unstable, rapid decomposition in water:

4 K3CrO8 + 2 H2O → 4 K2CrO4 + 4 KOH + 7 O2 ↑

Chromic Potassium Sulfate is oxidized and can be reduced by hydrogen sulfide, ammonium sulfide and other substances:

2 K2CrO4 + 3 H2S + 2 H2O → 2 Cr (OH) 3 ↓ + 4 KOH + 3 S

2 K2CrO4 + 3 (NH4) 2S + 8 H2O → 2 Cr (OH) 3 ↓ + 4 KOH + 3 S ↓ + 6 NH3 · H2O

Chromic Potassium Sulfate, sodium carbonate and sulfur eutectic, can be Na2Cr2S4:

4 K2CrO4 + 2 Na2CO3 + 8 S → 2 K2CO3 + 2 Na2Cr2S4 + 2 K2O + 7 O2 ↑

production method

1. Neutralization method Potassium dichromate dissolved in the mother liquor and water, adding to the reactor, adding potassium hydroxide under stirring to neutralize the reaction, the formation of Chromic Potassium Sulfate was weakly alkaline, concentrated by evaporation, cooling crystallization, solid Separated, dried, made of Chromic Potassium Sulfate finished. The K2Cr2O7 + 2KOH → 2K2CrO4 + H2O separation of the mother liquor, returned to the dissolved process for the solution of potassium dichromate.

2. The grinding of chromite and potassium hydroxide and limestone oxidation calcination, and then extracted with potassium sulfate solution derived.

Laboratory method: KOH, K2CO3, CrO4 mixed quickly heated to 400 ℃ for about 30 minutes. The resulting product was dissolved in water to remove the insoluble material and then heated to crystallize to obtain CAS 

No. .: 7789-00-6