Treatment system for secondary aluminum ash hydrolysis waste liquid

Abstract

The utility model relates to the technical field of chemical production, in particular to a treatment system for secondary aluminum ash hydrolysis waste liquid, which comprises a reaction kettle, a carbon dioxide gas source, an air compressor, a filter press and an absorption tower, a gas source input port and a discharge valve are arranged at the bottom of the reaction kettle, the gas source input port is respectively connected with the air compressor and the carbon dioxide gas source, the discharge valve is connected with a feeding port of the filter press through a pipeline, and a liquid phase output port of the filter press is connected with a feeding port of the reaction kettle through a pipeline; a gas outlet control valve is arranged at the top of the reaction kettle, the gas outlet control valve is connected with the absorption tower through a pipeline, and a stirring device is also arranged in the reaction kettle. According to the treatment system, the resource recovery rate of the secondary aluminum ash hydrolysis waste liquid can be effectively improved, and metal ion salt in the secondary aluminum ash hydrolysis waste liquid can be fully recovered.

Description

A treatment system for secondary aluminum ash hydrolysis waste liquid Technical Field

[0001] This utility model relates to the field of chemical production technology, and in particular to a treatment system for secondary aluminum ash hydrolysis waste liquid. Background Technology

[0002] Secondary aluminum ash is a solid waste generated after recovering metallic aluminum from primary aluminum ash. Its main hazardous component is aluminum nitride, along with small amounts of inorganic salts such as fluorides, sulfides, sulfates, and chlorides. Currently, the harmless treatment methods for secondary aluminum ash include wet and dry processes. Wet treatment involves using acid or alkali leaching to efficiently hydrolyze aluminum nitride and leach soluble salts. However, a large amount of recyclable resources still remain in the acidic or alkaline hydrolysate. Currently, the treatment of alkaline aluminum ash hydrolysate generally involves adding CO2 to directly recover aluminum hydroxide or adding hydrochloric acid to produce polyaluminum chloride. The resource utilization rate of aluminum ash hydrolysate is relatively low. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a treatment system for secondary aluminum ash hydrolysis waste liquid, which can effectively recover the utilization rate of aluminum ash hydrolysis liquid and fully recover the metal ion salts therein.

[0004] To address the aforementioned problems, this utility model proposes a treatment system for secondary aluminum ash hydrolysis waste liquid, comprising a reaction vessel, a carbon dioxide gas source, an air compressor, a filter press, and an absorption tower.

[0005] The bottom of the reactor is provided with a gas source inlet and a discharge valve. The gas source inlet is connected to the air compressor and the carbon dioxide gas source respectively. The discharge valve is connected to the feed inlet of the filter press through a pipeline. The liquid phase output port of the filter press is connected to the feed inlet of the reactor through a pipeline.

[0006] The top of the reactor is equipped with an exhaust control valve, which is connected to the absorption tower via a pipeline. The reactor is also equipped with a stirring device.

[0007] As an improvement to the above technical solution, the interior of the reactor is provided with a porous ceramic plate, which is located below the stirring device and is connected to the gas source inlet.

[0008] As an improvement to the above technical solution, the bottom of the porous ceramic plate is provided with a plurality of air-blowing nozzles arranged at a predetermined interval, and the air-blowing nozzles are connected to the air source inlet.

[0009] As an improvement to the above technical solution, the air source inlet is connected to the air compressor and the carbon dioxide gas source respectively through a three-way pipe, and a pipeline barometer is installed on the branch pipe connected to the air compressor and the carbon dioxide gas source.

[0010] As an improvement to the above technical solution, an extractant storage chamber is also included, which is connected to the feed inlet of the reactor via a pipeline;

[0011] The reactor is also equipped with a pH testing device.

[0012] As an improvement to the above technical solution, it also includes a first MVR evaporator and a second MVR evaporator;

[0013] The discharge valve of the reactor is connected to the feed port of the first MVR evaporator via a pipeline, and the liquid phase output port of the first MVR evaporator is connected to the second MVR evaporator via a pipeline.

[0014] As an improvement to the above technical solution, the stirring device includes a stirring motor and stirring blades. The stirring motor is fixed to the top of the reactor, and the rotating shaft of the stirring motor extends into the reactor through the top of the reactor. The stirring blades are disposed on the rotating shaft of the stirring motor.

[0015] As an improvement to the above technical solution, the reactor is also equipped with a barometer and a level gauge.

[0016] As an improvement to the above technical solution, a first liquid transfer pump is provided on the connecting pipe between the discharge valve and the feed inlet of the filter press, and a second liquid transfer pump is provided on the connecting pipe between the liquid phase output port of the filter press and the feed inlet of the reactor.

[0017] The following are the beneficial effects of implementing this utility model:

[0018] Compared to existing technologies, this invention adds an absorption tower and a filter press to the treatment system, and installs a liquid-phase circulation pipeline between the filter press and the reactor for treating wastewater. Specifically, the discharge valve of the reactor is connected to the inlet of the filter press via a pipeline, and the liquid-phase outlet of the filter press is connected to the inlet of the reactor via a pipeline. First, this treatment system uses air to aerate the wastewater in the reactor, and the blown-out ammonia gas is input to the absorption tower through the outlet control valve for absorption, forming ammonia water in the absorption tower. Second, the hydrolysis waste liquid is circulated multiple times between the reactor and the filter press through the liquid-phase circulation pipeline, thereby separating sodium carbonate, a high-value salt. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the composition of a processing system according to an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the connection of a reaction vessel according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0022] Referring to Figures 1 and 2, this embodiment of the present invention provides a treatment system for secondary aluminum ash hydrolysis waste liquid, including a reaction vessel 1, a carbon dioxide gas source 2, an air compressor 3, a filter press 4, and an absorption tower 5.

[0023] This embodiment of the invention improves the recycling rate of secondary aluminum ash hydrolysate by adding an absorption tower and a filter press, and by improving the circulation pipeline of the liquid phase.

[0024] Specifically, the bottom of the reactor 1 is provided with a gas source inlet 11 and a discharge valve 12. The gas source inlet 11 is connected to the air compressor 3 and the carbon dioxide gas source 2 respectively. The discharge valve 12 is connected to the feed inlet of the filter press 4 through a pipe. The liquid phase output port of the filter press 4 is connected to the feed inlet 13 of the reactor 1 through a pipe.

[0025] The top of the reactor 1 is equipped with an exhaust control valve 14, which is connected to the absorption tower 5 through a pipe. The reactor 1 is also equipped with a stirring device 15.

[0026] Compared to existing technologies, the treatment system of this invention adds an absorption tower 5 and a filter press 4, and sets up a liquid-phase circulation pipeline between the filter press 4 and the reactor 1 for treating wastewater. Specifically, the discharge valve 12 of the reactor 1 is connected to the inlet of the filter press 4 through a pipeline, and the liquid-phase outlet of the filter press 4 is connected to the inlet 13 of the reactor 1 through a pipeline. First, this treatment system uses air to aerate the wastewater in the reactor 1, and the blown ammonia gas is input into the absorption tower 5 through the outlet control valve 14 for absorption, forming ammonia water in the absorption tower 5; secondly, the hydrolysis waste liquid is circulated multiple times between the reactor 1 and the filter press 4 through the liquid-phase circulation pipeline, thereby separating sodium carbonate, a high-value salt.

[0027] Preferably, a porous ceramic plate 16 is provided inside the reactor 1 directly below the stirring device 15. The porous ceramic plate 16 has high corrosion resistance and is suitable for use in environments where it is immersed in secondary aluminum ash hydrolysis waste liquid for a long time. In addition, in order to increase the contact time between the gas blown into the porous ceramic plate 16 and the waste liquid, the gas blower nozzle 161 of the porous ceramic plate 16 is located at its bottom and is connected to the gas source inlet 11. Since the gas source inlet 11 is connected to the carbon dioxide gas source 2 and the air compressor 6 respectively, the gas blower nozzle 161 can selectively spray air or carbon dioxide.

[0028] Preferably, the gas source inlet 11 is connected to the air compressor 3 and the carbon dioxide gas source 2 respectively via a three-way pipe 111. Using the three-way pipe 111 facilitates the assembly and connection of the gas source inlet 11 with the air compressor 3 and the carbon dioxide gas source 2, and also facilitates the switching of the input gas. In addition, to monitor the operating status of the air compressor 3 and the carbon dioxide gas source 2 in real time, a pipeline barometer 112 is installed on the branch pipe connecting the air compressor 3 and the carbon dioxide gas source 2.

[0029] To further separate high-value salts from the secondary aluminum ash hydrolysis waste liquid, an extractant is required during the treatment process. Specifically, the system includes an extractant storage tank 6, which is connected to the feed inlet 13 of the reactor 1 via a pipeline; the reactor 1 is also equipped with a pH testing device 19.

[0030] The detailed extraction process is as follows: Carbon dioxide gas is continuously introduced into reactor 1 until the pH of its hydrolysate decreases to 6. A mixture of extractant and diluent is introduced into reactor 1 from extractant storage tank 6. The extractant includes one or more of alkyl primary amines, secondary amines, trioctylalkyl tertiary amines, and trioctylmethyl quaternary ammonium salts. The diluent includes one or more of kerosene, tributyl phosphate, n-pentanol, n-hexanol, n-octanol, and isooctanol, designated as the organic phase. With an organic phase to inorganic phase volume ratio of approximately 1:2, stirring and carbon dioxide gas are continuously injected until the pH drops from 5 to 3, at which point extraction stops. After extraction and separation, the organic and inorganic phases are obtained. The inorganic phase contains sodium chloride and sodium sulfate, and the organic phase contains ammonium chloride.

[0031] The ammonium chloride in the organic phase is back-extracted by the ammonia water obtained through absorption tower 4, and the resulting inorganic phase is concentrated and evaporated to obtain the ammonium chloride product.

[0032] Separating valuable salts from an inorganic phase requires the use of an MVR evaporator. Preferably, it also includes a first MVR evaporator 7 and a second MVR evaporator 8;

[0033] The discharge valve 12 of the reactor 1 is connected to the inlet of the first MVR evaporator 7 via a pipeline, and the liquid phase outlet of the first MVR evaporator 7 is connected to the second MVR evaporator 8 via a pipeline. The inorganic phase is fed into the first MVR evaporator 7 from the discharge valve 12 of the reactor 1, where it is evaporated and crystallized. When sodium sulfate is supersaturated, sodium sulfate and mother liquor are produced. Subsequently, the separated wood leaves are transported to the second MVR evaporator 8 for further evaporation to obtain sodium chloride product after supersaturation.

[0034] Preferably, the stirring device 15 includes a stirring motor 151 and a stirring blade 152. The stirring motor 151 is fixed to the top of the reaction vessel 1, and the rotating shaft of the stirring motor 151 extends into the reaction vessel 1 through the top of the reaction vessel 1. The stirring blade 152 is disposed on the rotating shaft of the stirring motor 151.

[0035] Preferably, the reactor 1 is also equipped with a barometer 17 and a level gauge 18.

[0036] Preferably, a first liquid transfer pump is provided on the connecting pipe between the discharge valve 12 and the feed inlet of the filter press 4, and a second liquid transfer pump is provided on the connecting pipe between the liquid phase output port of the filter press 4 and the feed inlet of the reactor.

[0037] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A treatment system for secondary aluminum ash hydrolysis waste liquid, characterized in that, The apparatus includes a reaction vessel, a carbon dioxide gas source, an air compressor, a filter press, and an absorption tower. The bottom of the reaction vessel is equipped with a gas source inlet and a discharge valve. The gas source inlet is connected to the air compressor and the carbon dioxide gas source, respectively. The discharge valve is connected to the feed inlet of the filter press via a pipeline. The liquid phase output port of the filter press is connected to the feed inlet of the reaction vessel via a pipeline. The top of the reaction vessel is equipped with an outlet control valve, which is connected to the absorption tower via a pipeline. A stirring device is also installed inside the reaction vessel.

2. The processing system as described in claim 1, characterized in that, The reactor is equipped with a porous ceramic plate located below the stirring device and connected to the gas source inlet.

3. The processing system as described in claim 2, characterized in that, The bottom of the porous ceramic plate is provided with a plurality of air-blowing nozzles arranged at a predetermined interval, and the air-blowing nozzles are connected to the air source inlet.

4. The processing system as described in claim 1, characterized in that, The air source inlet is connected to the air compressor and the carbon dioxide gas source respectively through a three-way pipe, and each branch pipe connected to the air compressor and the carbon dioxide gas source is equipped with a pipeline barometer.

5. The processing system as described in claim 1, characterized in that, It also includes an extractant storage chamber, which is connected to the feed inlet of the reactor via a pipeline; the reactor is also equipped with a pH testing device.

6. The processing system as described in claim 5, characterized in that, It also includes a first MVR evaporator and a second MVR evaporator; the discharge valve of the reactor is connected to the feed port of the first MVR evaporator through a pipeline, and the liquid phase output port of the first MVR evaporator is connected to the second MVR evaporator through a pipeline.

7. The processing system as described in claim 1, characterized in that, The stirring device includes a stirring motor and stirring blades. The stirring motor is fixed to the top of the reactor, and the rotating shaft of the stirring motor extends into the reactor through the top of the reactor. The stirring blades are mounted on the rotating shaft of the stirring motor.

8. The processing system as described in claim 1, characterized in that, The reactor is also equipped with a barometer and a level gauge.

9. The processing system as described in claim 1, characterized in that, A first liquid transfer pump is installed on the connecting pipe between the discharge valve and the feed inlet of the filter press, and a second liquid transfer pump is installed on the connecting pipe between the liquid phase output port of the filter press and the feed inlet of the reactor.

Images