The invention relates to a method for preparing subni oxide by reusing nickel precipitate. Firstly, the unqualified products produced by solution precipitation are screened to obtain a part of nickel precipitate with diameter > 5.0μm and a part of nickel precipitate with diameter ≤5.0μm. Then sediment diameter of 5.0 microns or less nickel and nickel salt solution to join the spray pyrolysis device, spray reaction, resulting atomized droplet during spray contains nickel deposits, in the pyrolysis reaction, nickel salt decomposition, together with the nickel deposits within the atomized droplets filled with nickel deposits, avoiding the hollowing out of the problems generated particles; Then, the nickel precipitate with diameter > 5.0μm was dissolved by acid solution prepared by spray pyrolysis, which saved the use of acid in the reverse dissolution process. In the whole process, the unqualified nickel precipitates are reused, turning waste into treasure and reducing the cost pressure brought by reverse dissolution. In addition, the invention also solves the existing spray pyrolysis technique was used to prepare high purity of the nickel oxide, nickel oxide obtained by by spray pyrolysis in addition to chloride, after high temperature calcination, and further get the higher purity nickel oxide powder, atomized droplets containing nickel deposits because of the spray, make the product with core-shell structure, further expand the product use, The viscosity and surface tension of the spray liquid can be further adjusted by adding additives to the spray pyrolysis device, which is conducive to the spray pyrolysis reaction. The invention has the advantages of simple operation and can be widely used in the production process of metal oxide powder, especially in the production process of preparing nickel oxide powder materials by reusing nickel precipitate.
The utility model relates to a method for preparing subnickel oxide by reusing nickel precipitate, which is realized by the following steps:
Step 1: The unqualified nickel precipitate obtained by solution precipitation method was screened, and the nickel precipitate with diameter ≤5.0μm was selected according to the required amount of subni oxide.
Step 2:1.7mol/l nickel salt solution was prepared by using nickel nitrate as raw material and adding pure water.
In step 3, the nickel precipitate selected in Step 1 and the nickel salt solution in step 2 are added to the spray pyrolysis device together, and then the polyethylene glycol (0.2% of the total mass of the solution) is added to the storage tank for stirring and mixing, so that the nickel precipitate is evenly dispersed in the nickel salt solution, which is conducive to spray pyrolysis to obtain product particles with higher consistency.
In step 4, the spray pyrolysis device was set as 0.2mpa, the pyrolysis temperature as 600℃ and the pyrolysis atmosphere as air atmosphere. The spray pyrolysis device was started to prepare nickel oxide. The tail gas generated by spray pyrolysis was cleaned to produce acid solution, which was used to dissolve the nickel precipitate with a diameter of > 5.0μm obtained by screening in Step 1.
Step 5: Send the nickel oxide prepared in step 4 into the chlorine removal device; The chlorine removal device uses water jet evaporation to remove chlorine. The nickel oxide obtained by spray pyrolysis at 600℃ is mixed with pure water sprayed in the spray device. The pure water quickly evaporates away the nitrate impurities in the nickel oxide particles.
Step 6: Set the high temperature calcination temperature as 700℃, adopt oxygen atmosphere, control oxygen partial pressure as 0.05mpa, and conduct high temperature calcination of nickel oxide after chlorine removal in step 5 to obtain subnickel oxide powder.