According to Baidu Encyclopedia, the components of electrolytic zinc purifying white solid purifying agent mainly include molecular sieve-like polymers with three-dimensional network structure of macromolecules. This is a water-soluble resin, which can be designed and synthesized according to the radius of different metal ions, so that impurity ions such as bivalent Ni and bivalent Cd with matching size are embedded and adsorbed in the mesh, and removed by coprecipitation, filter pressing and other means.