A method for separating and recovering aluminum, potassium and ammonium from a mixed solution containing aluminum sulfate, potassium sulfate and ammonium sulfate

Abstract

The invention provides a method of separating and recovering aluminum, potassium, and ammonium from a mixed solution containing aluminum sulfate, potassium sulfate, and ammonium sulfate. The method comprises following steps: evaporating and condensing the mixed solution, cooling the condensate to carry out crystallization to obtain mixed crystals of potassium alum and ammonium alum, burning the mixed crystals at a high temperature to prepare alumina, and recovering potassium sulfate and ammonium sulfate at the same time. The provided method can efficiently recover aluminum, potassium, and ammonium, and obtains high purity alumina, potassium sulfate, and ammonium sulfate, furthermore, the energy consumption is low, the investment is little, the production is carried out in an enclosed environment, no waste solid, waste gas or wastewater is discharged, the devices are easy to enlarge, and the industrial application prospect is good.

Description

technical field [0001] The invention relates to the field of separation and recovery, in particular to a method for separating and recovering aluminum, potassium and ammonium from a mixed solution containing aluminum sulfate, potassium sulfate and ammonium sulfate. Background technique [0002] The separation and recovery of metal ion-containing solutions is not only a difficult problem in industrial wastewater treatment, but also the key to improving product quality, purity and reducing wastewater discharge in mineral leaching, hydrometallurgy and other fields. Moreover, the mixed solution containing aluminum sulfate, potassium sulfate and ammonium sulfate is a common intermediate solution or waste water in industry, such as the waste water produced by active clay, the vanadium precipitation waste water and the process liquid in the comprehensive utilization of potassium feldspar. At present, the methods for removing metal ions are mostly precipitation method, living body p...

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Problems solved by technology

Commonly used in water treatment process, its operation cycle is long, its ability to deal with heavy metals is poor, and it is easy to cause water pollution during the discharge process

[0004] The precipitation method is aimed at heavy metals, adjusting the pH of the system and precipitating heavy metal ions. This process consumes a lot of reagents, and the precipitation efficiency is not ideal according to the nature of the solution.

[0005] CN101343695A discloses a method for reducing the content of potassium and sodium in the leaching circulation liquid for extracting vanadium. First, the solution is adjusted to acidity, and the potassium and sodium removal agent containing iron ions is added by heating to control the pH value to cause a precipitation reaction. This precipitation method can effectively reduce the Potassium and sodium content in the circulating liquid, but the requirements for the concentration of other metal ions in the raw material liquid are relatively high, and the recycling of potassium and sodium is not considered, and the sediment is still a solid waste, which is difficult to handle

[0006] CN105217658A discloses a method for directly extracting potassium and aluminum from alunite by pressurized acid leaching, in which potassium sulfate solution and aluminum hydroxide-containing gypsum slag are prepared through lime water slurrying reaction, the method can extract potassium and aluminum in alunite Separation, acid leaching mother liquor can be recycled, but this method uses lime water to adjust the pH to precipitate aluminum hydroxide, and at the same time will carry a large amount of precipitation of other metal impurities, the purity of the prepared aluminum hydroxide is not good

[0007] Adsorption method is a kind of method that uses solid surface energy to produce specific adsorption on heavy metal ions to achieve the purpose of removing heavy metals. The adsorption process is often accompanied by ion exchange and chelation. The adsorption method has strong adsorption for heavy metals and is easy to operate. Simple, but its adsorption selectivity is poor, desorption is difficult, and the separation and recovery of metal impurities still cannot be achieved

[0008] CN103539177A discloses a process for producing aluminum hydroxide by utilizing potassium feldspar, which absorbs aluminum ions and iron ions in the dilute sulfuric acid leaching solution of potassium feldspar through a cation adsorption column to enrich the aluminum ions and iron ions, and then uses Dilute sulfuric acid with a concentration of 3wt% to 5wt% desorbs the saturated cation adsorption column to separate aluminum ions from potassium ions. This method also needs to use an extraction liquid to extract the desorbed solution, and the process steps are complicated. , the cationic adsorption resin has a short service life and high cost

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