Study on Preparation of Nano-ZnO by Zinc Hypoxide in Rotary Hearth Furnace

Abstract

To realize the high value-added utilization of zinc hypoxide in a rotary hearth furnace, nano-ZnO was prepared by H2SO4 wet leaching combined with the Na2CO3 precipitation process. The effects of different process conditions on the leaching rate of Zn were analyzed, and the feasibility of preparing nano-ZnO from zinc hypoxide was discussed. The results showed that the optimal process conditions for H2SO4 leaching of zinc hypoxide in a rotary hearth furnace were as follows: H2SO4 concentration 2.0 mol·L−1, leaching temperature 60 °C, leaching time 90 min, and liquid-solid ratio 8:1. Under these conditions, the leaching rate of Zn reached 95%. The calculation results of leaching kinetics showed that the restrictive link of the H2SO4 leaching process was a chemical reaction process; the apparent activation energy was 14.45 kJ·mol−1; and the reaction order was 0.6. The precursor obtained by Na2CO3 precipitation treatment was Zn5(OH)6(CO3)2. After calcination at 400 °C, the nano-ZnO with a diameter of less than 100 nm and length greater than 1 μm was obtained. H2SO4 leaching combined with the Na2CO3 precipitation process provided a new approach for high value-added utilization of zinc hypoxide in a rotary hearth furnace.