Method for manufacturing zinc sulfate by utilizing high-grade arsenic zinc oxide and zinc ash from steel works

Abstract

The invention relates to a method for manufacturing zinc sulfate by utilizing high-grade arsenic zinc oxide and zinc ash from steel works, which comprises the following steps: calculating the use amount of the two raw materials: high-grade arsenic zinc oxide and zinc ash from steel works according to the lab results of the elements arsenic, ferrum and zinc in the two raw materials; mixing the rawmaterials; and evaporating and crystallizing after pulpifying, lixiviating, adjusting pH value, oxidizing to remove ferrum and arsenic, neutralizing, filtering by pressing and purifying to obtain qualified zinc sulfate products. The invention is highly adaptable to high-grade arsenic materials and can process zinc oxide materials containing 1.5-2.5 percent of arsenic. The manufacturing process issafe and reliable, and no such personal injury caused by accidents as AsH3 poisoning occurs, thus clean manufacturing can be realized to prevent arsenic from causing secondary pollution; the raw materials are easy to obtain, and the products have high quality meeting the II class standard (zinc sulfate heptahydrate) respectively in HG 2934-2000 (feed-grade zinc sulfate) and HG / T2326-2005 (industrial zinc sulfate).

Description

technical field [0001] The invention relates to a production process method of zinc sulfate, in particular to a method for producing zinc sulfate by utilizing high-arsenic zinc oxide and iron and steel factory zinc dust. Background technique [0002] my country's existing lead smelting capacity is 3.5 million tons, with an annual output of more than 2.8 million tons of refined lead. In the process of lead smelting, 550,000 tons of zinc oxide with a grade of 60% to 70% can be produced every year, of which the zinc content reaches about 300,000 tons . Since the content of arsenic in this low-grade zinc oxide is as high as 1.5% to 2.5%, and arsenic and its compounds are highly toxic substances, the content of arsenic in feed grade, agricultural fertilizer grade and even some zinc sulfate products used in industrial production has been raised. The national standard requires the arsenic content to be below 5PPm, while the requirements abroad (especially the European Union and Nor...

AI Technical Summary

Problems solved by technology

For general industrial wastewater treatment to remove arsenic, the solution will be adjusted to neutral or alkaline with lime first, then sulfide precipitation method can be used to remove arsenic, the principle is As 3+ and As 5+ Both and S 2- Formation of sulfide salt precipitation, but these two types of precipitation cannot be preferentially formed over zinc sulfide in an acidic environment, so they cannot be used in the production of zinc sulfate

Another example is the use of manganese dioxide to oxidize As in the production process of electrolytic zinc 3+ , making it generate As 5+ , As 5+ Then combine with metal ions to form arsenate precipitation, so as to achieve the purpose of removing arsenic, but this method will introduce Mn 2+ ions, so that the zinc sulfate solution is light red, which is harmful to the appearance quality of zinc sulfate products, and potassium permanganate needs to be used to remove Mn 2+ , so that the cost increases more and the operation is more cumbersome

It is also useful to add lime to generate Ca 3 (AsO 3 ) 2 Arsenic is removed by precipitation method, but the precipitate is more soluble in acid, so it cannot completely remove arsenic when it is used in the production of zinc sulfate

Potassium permanganate is also used to remove arsenic, but potassium permanganate and As 2 o 3 Generate As 2 o 5 The reaction can only be applied to neutral or alkaline environment, and arsenic cannot be completely removed when applied to the production of zinc sulfate; such as potassium permanganate and AsO 3 3+ The reaction will generate Mn 2+ ion, also not suitable for zinc sulfate production