Process for separating and recovering zinc magnesium sulfate double salt from sulfate solution and application thereof

A technology for separation and recovery, sulfate, applied in zinc compounds, chemical instruments and methods, inorganic chemistry and other directions, can solve the problem of zinc and magnesium losing the value of recycling, and achieve the effect of less reagent consumption, clean process and environmental protection

Active Publication Date: 2020-07-10
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most of the solutions containing zinc sulfate and magnesium sulfate are neutralized with lime before discharge, and zinc, magnesium and sulfate are removed by precipitation with zinc hydroxide, basic zinc sulfate, magnesium hydroxide and calcium sulfate. The method can remove harmful components such as zinc, magnesium, and sulfate radicals, but zinc and magnesium lose their recycling value

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Get the sulfate solution 10L that chemical plant produces (its solution temperature is 65 ℃, main chemical composition is zinc 130g / L, magnesium 28g / L, other element concentrations are all lower, and sulfuric acid concentration is 0.2g / L in the solution. At first Add this sulfate solution into the pre-cooler, use the crystallization mother liquor with a temperature of -5°C for heat exchange pre-cooling, and cool it to 30°C. Then add the pre-cooled solution into the crystallization reactor. Use a coil heat exchanger Cool down, start stirring, and the stirring speed is 30 rpm. In the first stage, the cooling rate is 0.2°C / min. When cooling to 15°C, the solution starts to become turbid, stop cooling, keep warm and stir for 30min. Then start The second stage cooling, with the cooling rate being 0.5 ℃ / min cooling rate to be cooled to-5 ℃, be incubated and stir 60min.After reaction finishes, adopt centrifugal filter to filter, filter product oven dry and obtain 3500g zinc-magn...

Embodiment 2

[0022] Take 10L of sulfate solution produced by the smelting plant (the temperature of the solution is 40°C, the main chemical components are zinc 40g / L, magnesium 26g / L, sulfuric acid 180g / L and other element concentrations are low). Firstly, put the sulfate solution into the pre-cooler, use the crystallization mother liquor with a temperature of -10°C for heat exchange and pre-cooling, and cool to 10°C. The pre-cooled solution is then added to the crystallization reactor. Use a coil heat exchanger to cool down, start stirring, and the stirring speed is 60 rpm. In the first stage, the cooling rate was 0.3 °C / min. When the temperature was lowered to 0 °C, the solution began to become cloudy, so the cooling was stopped, and the temperature was kept and stirred for 20 min. Then start the second stage of cooling, and lower the temperature to -10°C at a cooling rate of 0.8°C / min, keep warm and stir for 40min. After reaction finishes, adopt centrifugal filter to filter, and filte...

Embodiment 3

[0024] Take 10L of sulfate solution produced in the printing and dyeing industry (the temperature of the solution is 25°C, the main chemical components are zinc 75g / L, magnesium 87g / L, and the concentration of sulfuric acid is 75g / L). First, add the sulfate solution into the pre-cooler, use crystallization mother liquor at 0°C for heat exchange pre-cooling, and cool to 15°C. The pre-cooled solution is then added to the crystallization reactor. Use a coil heat exchanger to cool down, start stirring, and the stirring speed is 100 rpm. In the first stage, the cooling rate was 0.5°C / min. When the temperature was lowered to 10°C, the solution began to become turbid, so the cooling was stopped, and the temperature was kept and stirred for 30 minutes. Then start the second stage of cooling, and lower the temperature to 0 °C at a cooling rate of 1 °C / min, keep warm and stir for 60 min. After reaction finishes, adopt centrifugal filter to filter, and filter product oven dry obtains 4...

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PUM

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Abstract

The invention relates to a process for separating and recovering zinc magnesium sulfate double salt from a sulfate solution and an application thereof, which belongs to the technical field of wastewater treatment. The method comprises the following steps: adding a sulfate solution into a precooler, carrying out heat exchange precooling by using a crystallization mother solution, adding into a crystallization reactor, cooling at a cooling rate of 0.2-0.5 DEG C / min in the first stage, stopping cooling when the solution begins to become turbid, and carrying out heat preservation stirring for 15-30 minutes; and in the second stage, cooling at the cooling rate of 0.5-1 DEG C / min, controlling the final temperature to be lower than the temperature in the first stage by 10 DEG C or above and higher than the freezing point temperature of the solution, and performing heat preservation and stirring for 20-60 min. After the reaction is finished, filtering is carried out by adopting a centrifugal filter to obtain a zinc-magnesium sulfate double-salt product, and the crystallized mother liquor obtained by filtering is returned to the precooler to serve as a precooling medium.

Description

technical field [0001] The invention relates to a process and application for separating and recovering zinc-magnesium sulfate double salt from a sulfate solution, and belongs to the technical field of wastewater treatment. Background technique [0002] With the rapid development of my country's economy, the scale of some industrial enterprises has been further expanded, but the problem of wastewater treatment in the production process has become increasingly prominent. In chemical industry, smelting, printing and dyeing and other industries, a large amount of waste sulfate solutions will be produced. Since these solutions contain a large amount of heavy metal sulfate substances, if they cannot be treated well and are directly discharged into water bodies as waste water, it will cause serious damage to the environment. Great harm to the ecological environment. [0003] At present, most of the solutions containing zinc sulfate and magnesium sulfate are neutralized with lime ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G9/00
CPCC01G9/006
Inventor 李兴彬邓志敢魏昶李旻廷樊刚李存兄江国豪世仙果
Owner KUNMING UNIV OF SCI & TECH
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