The invention discloses a method for preparing nano
calcium carbonate by efficiently removing iron impurities in nano
calcium carbonate raw material ore, and belongs to the technical field of nano material preparation. The method comprises the steps of
raw material pretreatment,
digestion treatment, size mixing treatment,
carbonization treatment, surface treatment and
drying, in the size mixing treatment process, a whitening agent Na2SO3 is adopted for removing iron in
raw material ore, Na2SO3 serves as a
reducing agent, Fe < 3 + > is reduced into Fe < 2 + >, a proper amount of whitening auxiliary such as DTPA or
triethanolamine forms colorless water-containing
iron chelate ions with iron ions, and the
iron chelate ions are subjected to surface treatment. And through a synergistic
system of the whitening agent and the whitening auxiliary agent, efficient removal of iron is realized. The whiteness of the prepared nano
calcium carbonate reaches up to 97.2%, the nano
calcium carbonate has the remarkable advantages of being efficient,
environmentally friendly, economical and the like, the
iron content in the nano
calcium carbonate can be remarkably reduced, the purity and whiteness of the product are effectively improved, and the high requirement of the high-end application field for the quality of the nano
calcium carbonate is met. Meanwhile, the method is simple and convenient to operate and easy to industrially apply, and has wide market prospects and popularization value.