Background and overview[1][2]
Manganese acid phosphate is also called Mariv salt or manganese dihydrogen phosphate. It is a white or light pink crystalline powder. It dissolves in water and undergoes hydrolysis to form a flocculent precipitate. The solution is acidic, insoluble in alcohol, and hygroscopic. It is very easy to deteriorate when in contact with oxides and has corrosive effects. It dehydrates into anhydrous matter when the temperature is higher than 100°C. It can be used for phosphating treatment on steel surfaces.
Production method[1]
Electrolytic manganese method: Electrolytic manganese reacts with phosphoric acid to synthesize acid manganese phosphate, and a small amount of iron is added to the reaction, and then concentrated, crystallized, and centrifuged to dryness to obtain pure product.
Content determination[1]
1. Determination of phosphoric acid and phosphate content
The quinolinone gravimetric method is uniformly used, which is a classic method for determining phosphorus pentoxide at home and abroad.
2. Determination of manganese (Mn) content
Manufacturers often use the potassium permanganate method for corporate standards. The manufacturer reported that the end point of this method is difficult to observe and the error is large. The ferrous ammonium sulfate method can be used for determination. The method is accurate and the end point jumps sensitively.
3. Determination of iron (Fe) content
Manufacturers and enterprises often use the potassium permanganate method for standardization. The end point of this method is difficult to observe and has large errors. GB/T3049-86 “General method for determination of iron content in chemical products-phenanthroline spectrophotometry” can be used. This method is accurate, scientific and advanced.
4. Determination of sulfate (measured as SO4) content
Each company has different standard methods, and the barium sulfate visual turbidimetry method can be used.
5. Determination of total acidity (titer)
Calibration using sodium hydroxide standard titration solution.
6. Determination of hydrolyzable insoluble matter content
Determined using the glass sand crucible gravimetric method.
7. Determination of weight loss by heating
Determined by gravimetric method.
Apply[3]
CN201510844019 discloses a surface anti-corrosion treatment agent for metal materials. The anti-corrosion treatment agent consists of 20-30 parts of manganese acid phosphate, 20-30 parts of zinc dihydrogen phosphate, 1-3 parts of potassium fluozirconate, and It consists of 1-3 parts of acid, 3-5 parts of citric acid, 0.5-1 part of emulsifier, 2 parts of vinyl silane 1pvc stabilizer, 2-4 parts of epoxy silane and an appropriate amount of phosphating accelerator. The invention overcomes the shortcomings of the existing technology, has stable solution, simple process control process, good corrosion resistance, reduces heavy metal ions, low VOC, less sediment, less pollution, high efficiency and wide application range before metal surface coating. Pretreatment with water-based treatment agent.
