Method for refining multistage circulation evaporation-free copper sulfate

Abstract

The invention provides a method for refining multistage circulation evaporation-free copper sulfate. The method comprises the following steps: adding crude copper sulfate to be refined in a saturated solution, heating and filtering to obtain a high-temperature high-concentration copper-containing solution; conventionally cooling and crystallizing; and carrying out centrifugal separation to obtain first grade refined copper sulfate and a first grade crystallized mother liquid; taking the first grade refined copper sulfate as the crude copper sulfate to be refined, and repeating the above step until the obtained refined copper sulfate conforms to the quality requirements of a copper sulfate product; and washing by water to obtain the copper sulfate product by refining. The method is low in energy consumption, low in water consumption amount and rapid in speed; the produced copper sulfate product is high in quality and low in production cost; the method is convenient for waste liquid to be recovered and treated; low-pressure steam can be utilized, so that the efficiency of heat utilization of the steam is improved; and the copper sulfate products in various quality grades can be produced according to the market demands.

Description

technical field [0001] The invention relates to a method for refining crude copper sulfate, which belongs to the technical fields of chemical industry and metallurgy. Background technique [0002] Copper sulfate pentahydrate is a commonly used chemical product, especially in electrolytes, pigments, pesticides, preservatives, additives, pharmaceuticals and the production of electronic products that require high-purity copper sulfate. [0003] The conventional process for producing copper sulfate is to extract copper-containing materials with dilute sulfuric acid, filter, purify the filtrate, evaporate and concentrate, cool and crystallize, and centrifuge to produce copper sulfate products. However, because the raw materials contain more impurities, the obtained copper sulfate products The quality is not high. In order to obtain high-quality copper sulfate products, it often needs to be refined. Some processes for preparing copper sulfate have been proposed. [0004] The recr...

AI Technical Summary

Problems solved by technology

[0008] In order to ensure the quality of copper sulfate products in the existing public technology, it is often necessary to add various reagents to purify the copper sulfate solution, which will lead to the introduction of impurity ions and increase the cost, produce copper-containing purification slag, and reduce the recovery rate of copper; or use Copper-containing raw materials with less impurities lead to an increase in raw material costs and a decline in economic benefits; or a method of discharging part of the crystallization mother liquor or initial crystallization from the system, which in turn leads to a decrease in recovery rate and production efficiency

[0009] Although the above methods can obtain high-quality copper sulfate, they all have evaporation, concentration and crystallization process, which has the following disadvantages: (1) In order to avoid the difficulty of filtering due to the high concentration of copper sulfate solution, it is necessary to configure unsaturated copper sulfate solution at room temperature, which requires a large amount of New water dissolves crude copper sulfate, and the water consumption is large; (2) During the concentration process, in order to increase the crystallization rate, the solution is often concentrated to a high-temperature saturated state, which makes the solution unable to be filtered, and because the concentration of copper sulfate in water increases during the concentration process, The boiling point of the solution rises, and the temperature of the liquid after high-temperature concentration is often higher than 100°C. In order to further evaporate water, more high-pressure steam will be consumed, and a large amount of exhaust steam will be generated, which is difficult to use, with low steam utilization rate and high energy consumption. A large amount of water; (3) While evaporating and concentrating to obtain high-temperature copper sulfate saturated liquid, the impurities in the solution are also concentrated, and precipitate out at the same time as copper sulfate crystallization, resulting in low product quality; in order to obtain higher quality copper sulfate products, usually Requires deep purification or multiple recrystallizations of the copper sulfate solution, ultimately resulting in low yields and low metal recovery

At the same time, the process of evaporating a large amount of water is slow and there are many equipments, resulting in high production cost of copper sulfate

Images