Novel method for producing nanometer grade zinc carbonate and zinc oxide

Abstract

The invention relates to a novel method for producing nanometer grade zinc carbonate and zinc oxide, which comprises the following process steps: firstly, placing a metered zinc sulfate (ZnSO4) solution with the specific gravity of 30 to 31 baumes into a double decomposition kettle; then, slowly adding a sodium carbonate water solution containing 28 to 30 percent of sodium carbonate (Na2CO3) into the double decomposition kettle in two times after the filtration for forming mixed material pulp mainly containing nanometer grade (the fineness degree reaches 600 to 800 nanometers) basic zinc carbonate (Zn(OH)2.ZnCO3); then, carrying out pressure filtration on the mixed material pulp mainly containing the nanometer grade basic zinc carbonate; using water for washing sulfate radical (SO4<2->) ions in a filter press; then, sending the materials into a drying chamber to be dried; then, using a crushing machine for sending the materials into a rotary flash evaporation drying machine to be calcined; and next, sending the materials into a dust collection chamber to obtain the nanometer grade zinc carbonate (ZnO). Compared with the prior art, the invention has the characteristics of fine fineness degree of the zinc carbonate, large specific surface area, short calcining time, low energy consumption and the like.

Description

technical field [0001] The invention relates to a method for producing zinc carbonate and zinc oxide by metathesis, in particular to a new method for producing nano-scale zinc carbonate and zinc oxide. Background technique [0002] The existing process for producing zinc oxide is: first, the specific gravity is 30-31 Bomei zinc sulfate (ZnSO 4 ) aqueous solution into the metathesis kettle, and then containing sodium carbonate (Na 2 CO 3 ) 28%-30% sodium carbonate aqueous solution is filtered and added in the metathesis kettle, the pH value of the zinc sulfate aqueous solution in the metathesis kettle is neutralized to 6.8-7.0 to form a basic zinc carbonate with a fineness of 300-800 microns (Zn(OH) 2 .ZnCO 3 ) mixed slurry, press-filter the upper-speed mixed slurry, and wash the sulfate radical (SO 4 ) ion, sent to the drying room for drying, the drying temperature is 110-140 ° C, dried to the basic zinc carbonate with a zinc (Zn) content of 50-55%, crushed by a crusher...

AI Technical Summary

Problems solved by technology

[0004] 1. The molecular structure of basic zinc carbonate is unreasonable: because the sodium carbonate aqueous solution is added to the metathesis kettle at one time during metathesis, and the pH value of the zinc sulfate aqueous solution in the metathesis kettle is directly neutralized to 6.8-7.0, resulting in the formation of Basic Zinc Carbonate (Zn(OH) 2 .ZnCO 3 ) in the molecular structure of zinc carbonate molecules is more than the number of zinc hydroxide molecules, reducing the zinc content in basic zinc carbonate, causing the molecular lattice of basic zinc carbonate to be thick, and decarburization energy consumption delay;

[0005] 2. The fineness of zinc oxide is coarse and the specific surface area is small: due to the low drying temperature of basic zinc carbonate (110-140°C), the carbon dioxide escapes slowly during drying, and the sublimation pressure of carbon dioxide cannot be formed (the sublimation pressure of carbon dioxide rises during calcination Dispersion), so the fineness of zinc oxide is coarse, the specific surface area is small, and the scope of use is limited;

[0006] 3. Long calcination time and high energy consumption: due to the low calcination temperature of basic zinc carbonate (450-500°C), only the sublimation temperature of carbon dioxide is considered, and the heat absorption of carbon dioxide is not considered, resulting in the actual temperature of the product during calcination. 250-300°C, so the calcination time is long, the energy consumption is high, and the product quality is affected