Method for removing chlorine from solution of zinc sulfate

Abstract

The invention discloses a method for chlorine from solution of zinc sulfate, which mainly comprises the following: 1, a step of extraction, in which tributylamine is used as an extractant, kerosene or para-octanol is used as diluent, clear liquid of zinc sulfate is mixed with an organic phase for extraction, and chlorine in a water phase is transferred to an organic phase; 2, a step of back extraction, in which back extraction is performed by using ammonia water or solution of sodium hydroxide, chlorine in the organic phase is retransferred to the water phase, and the organic phase is recycled; 3, a step of organic phase regeneration, in which 5 to 10 percent solution of sodium hydroxide is mixed with the organic phase which ages after being used for a certain period of time in a ratio of 1:0.9 to 1:2.5, and the mixture is stirred by an electromagnetic siterr at a high speed for 8 to 15 minutes for regenerating the organic phase; and 4, a step of deoiling, in which raffinate is subjected to active carbon absorption or ultrasonic demulsification so as to remove the organic phase in the raffinate. In the invention, the organic phase and the raffinate can be used circularly, the dechlorination rate is over 85 percent, the electrolytic operation environment is improved, the process flow is simple, and the method can be used for dechlorinating solution of zinc sulfate from wet-method zinc smelting plants and can also be used for dechlorinating wastewater.

Description

Technical field [0001] The invention relates to a hydrometallurgical zinc smelting process of zinc metal, in particular to a method for removing chlorine from a zinc sulfate solution. Background technique [0002] Hydro-zinc smelting is currently a common zinc smelting process. According to its process requirements, the chlorine content in the zinc sulfate solution should not exceed 300mg / L during zinc electrolysis. The best effect is if the chlorine content is controlled below 200mg / L, otherwise It will cause many inconveniences to zinc electrowinning, seriously affecting the efficiency of zinc electrowinning and the quality of electro-zinc products, causing serious corrosion of anode plates, increasing production costs, and severely deteriorating the environment of the production workshop. Therefore, hydro-zinc smelters are actively seeking effective dechlorination methods. The main two types of dechlorination methods are fire and wet. Fire dechlorination mainly uses multi-hear...

AI Technical Summary

Problems solved by technology

[0002] Zinc hydrometallurgy is a commonly used zinc smelting process at present. According to its process requirements, the chlorine content in the zinc sulfate solution is required not to exceed 300mg / L during zinc electrolysis. It is best if the chlorine content is controlled below 200mg / L, otherwise It will bring a lot of inconvenience to the electrowinning of zinc, seriously affect the electrolytic efficiency of zinc electrowinning and the quality of electrolytic zinc products, and cause serious corrosion of the anode plate, increase production costs, and seriously deteriorate the environment of the production workshop

Therefore, the wet zinc smelting manufacturers are actively looking for effective dechlorination methods, mainly fire and wet dechlorination methods, fire dechlorination mainly uses multi-hearth furnace roasting dechlorination for solid materials such as zinc ore, This method has incomplete dechlorination, a lot of dust, and disadvantages such as poor environment; the other is wet dechlorination, which is to dechlorinate liquid materials such as zinc sulfate solution. The prior art of wet dechlorination needs to consider solution acidity and Restrictions on total volume and other conditions, specifically including alkali elution dechlorination method, copper slag dechlorination method, zinc powder + copper sulfate dechlorination method and thorium salt dechlorination method, etc., copper slag dechlorination method, zinc powder + copper sulfate dechlorination method When other methods are used for dechlorination from zinc sulfate solution, the pH value of the solution is strictly required, and the pH requirement is not greater than 3, and the dechlorination efficiency can generally only reach 70%. When the pH value is greater than 3, the dechlorination effect is remarkable Decrease, the generated cuprous chloride slag decomposes into cuprous oxide as the pH value of the solution increases, and chlorine will transfer into the zinc sulfate solution again

Although the pH value can be reduced to 3 by adding waste acid, this not only destroys the acidity balance of the system, but also increases the follow-up operation cost, the dechlorination effect can only be about 70%, and the chlorine content in the solution after dechlorination still reaches 250mg / L ;Thorium salt dechlorination method is difficult to apply in zinc hydrometallurgy due to its high cost

Therefore, the prior art of wet dechlorination has not yet solved the problem of achieving an ideal dechlorination effect under the conditions of limited solution acidity and total volume. How to effectively dechlorinate from zinc sulfate solution is a difficult problem to be further explored.

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