Extractive preparation method of high-purity zinc oxide

Abstract

The invention discloses an extractive preparation method of a high-purity zinc oxide. The method comprises the following steps of: firstly, directionally dissolving a zinc-containing raw material in 50 to 65 percent solution of caustic soda; adding an extracting agent into solution of sodium zincate produced by directional dissolving for extracting so as to produce zinc oxide which contains crystal water and recycling the extracting agent produced through distillation treatment; and washing, drying, and calcining the zinc oxide which contains crystal water so as to obtain finished high-purityzinc oxide. When the zinc oxide, which contains crystal water, produced by extraction is washed, dried and calcined, carbon dioxide is not produced; produced distilled water can be used for washing the zinc oxide which contains crystal water; washed and filtered fluid is used for washing dissolved slag formed after directional dissolving; and liquid in the entire treatment process is used circularly in a closed loop, so that waste water and waste gas are not discharged. The zinc oxide content is over 99.9 percent, the lead content is less than 5PPm and the method has wider application and wider application field.

Description

technical field [0001] The present invention relates to a kind of zinc oxide, in particular to a kind of manufacturing method of zinc oxide. Background technique [0002] The traditional manufacturing method of zinc oxide is usually prepared by acid method or ammonia method in wet method. The two use acid or alkali to react with zinc-containing raw materials respectively, and then prepare basic zinc carbonate precipitation. After filtering, washing, drying and calcining at about 800°C, high-purity light zinc oxide with a particle size of 1-100 nanometers is finally obtained. [0003] The acid preparation of the above-mentioned zinc oxide manufacturing method is usually to react zinc-containing raw materials with sulfuric acid to obtain an impure zinc sulfate solution containing heavy metal ions. Then, through oxidation removal, reduction removal and multiple precipitation, a large amount of metal ions such as iron, manganese, copper, lead, cadmium and arsenic are removed t...

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Problems solved by technology

The cost of the ammonia method is relatively low, but it has great restrictions on the raw materials used. Generally, the purity of zinc oxide products can only reach 99%. For details, see the zinc oxide standard: GB / T 19589-2004

Because the above-mentioned leaching solution is a zinc-ammonia complex solution, many other metal ions will also form relatively stable complex ions with ammonia, which is difficult to eliminate during the impurity removal treatment, so the purity of zinc oxide products can generally only reach 99%.

Moreover, in the calcination process, since the basic zinc carbonate is calcined, when the basic zinc carbonate decomposes to zinc oxide, a large amount of carbon dioxide will inevitably be produced, resulting in exhaust gas emissions.

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