Sodium pyrophosphate reacts with copper sulfate or copper chloride to produce copper pyrophosphate.
Na4P207+ 2cucL2-Cu2p207 +4NaCl
Sodium pyrophosphate (95%) 950
Copper sulfate (93%) 1450
Using industrial hydrated disodium phosphate as raw material, it is heated and dehydrated at low temperature, and then slowly heated to about 100℃, so that it removes all the crystalline water and becomes anhydrous salt. Ground anhydrous salt, and then put it in a high temperature furnace, hot at 200-300℃, to produce sodium pyrophosphate.
The reaction is complete when it is burned to test the presence of phosphate free ions. The test method is: take a little sample in the test tube, dissolve it with deionized water, then add 2-3 drops of silver nitrate solution, no yellow precipitate, only white precipitate, indicating the presence of phosphoric acid ions.
After the condensation reaction was completed, the sodium pyrophosphate was cooled to room temperature, dissolved in deionized water and prepared into a solution with a density of about 1.2g/mL. Heated to 80-90℃, activated carbon was added for decolorization, and impurity removal was filtered to obtain sodium pyrophosphate solution.
The industrial copper sulfate was dissolved in deionized water and prepared into a solution with a density of about 1.2g/mL. The pH was adjusted to 4-5 with sodium hydroxide solution, and then heated to 80-90℃. The iron in the solution was hydrolyzed and precipitated fully, and the impurities were removed by filtration.
Preparation of copper pyrophosphate: The above prepared sodium pyrophosphate solution is put into the reaction kettle with stirring device, and the purified copper sulfate solution is slowly added according to stoiometry under stirring. The solution is dark blue at first, and with the continuous addition of copper sulfate solution, grayish-blue or light green precipitation is gradually produced. After the precipitation is complete, the solution is aged for several hours, filtered, and the filtrate is concentrated into sodium sulfate byproducts through evaporation. The cake is washed several times in deionized water until no sulfate ions are present. The test method is: take 2mL of washing water, add a few drops of dilute hydrochloric acid, then add 2-3 drops of barium chloride solution, no turbidity phenomenon, that is, no sulfate ion.
The washed precipitate was centrifuged to remove water, and then dried at 140-160℃. After grinding, loose copper pyrophosphate was obtained.
Used for cyanide-free electroplating, is the main component of copper plating solution. Electroplating products have the characteristics of corrosion resistance and good luster.