Method and system for purifying impurities in mother liquor

Abstract

A method and system for purifying impurities in mother liquor belong to the technical field of alumina wet production, and the method comprises the following steps: mixing pulverized coal and cooled mother liquor, placing the mixture in a mixing tank, after the pulverized coal adsorbs the impurities in the mother liquor, conveying the pulverized coal to a filter through a conveying pump, and separating the adsorbed slurry, filtered filtrate enters a filtrate tank and then is sent back to a production system for utilization through a filtrate pump, filter residues are conveyed to a combustion furnace through a conveyor to be combusted, and organic matter in the filter residues is removed. Organic matter in the production process is removed through an adsorption method and a combustion method, the removal effect is more thorough, and the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of wet production of alumina, and particularly relates to a method and a system for purifying impurities in mother liquor. Background Art

[0002] In the process of alumina production, organic carbon in the ore enters the production process during the digestion process and accumulates continuously in the system. As the solution is recycled continuously, the concentrations of oxalates, carbonates, and humus-like organic substances in the system increase continuously, which will affect the digestion flash evaporation process and the decomposition process, cause scaling on equipment, reduce the heat exchange efficiency of heat exchange equipment, and affect the product quality. Therefore, it is necessary to discharge the organic substances in the system.

[0003] At present, in the alumina production process, the fine seed washing method and the mother liquor cooling crystallization method are mostly used to remove organic substances, and there is also the mother liquor combustion method to remove organic substances. However, these methods can only remove oxalates, or have too high costs, cannot completely eliminate the influence of organic substances, and have poor economy. Summary of the Invention

[0004] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a method and a system for purifying impurities in mother liquor, aiming to use the adsorption method and the combustion method to remove organic substances in the production process, with a more thorough removal effect and reduced costs.

[0005] In order to achieve the above object, the main technical solutions adopted by the present invention include: A method for purifying impurities in mother liquor, comprising the following steps: mixing pulverized coal with the cooled mother liquor in a mixing tank, and after the pulverized coal adsorbs the impurities in the mother liquor, conveying it to a filter press through a delivery pump to separate the adsorbed slurry, the filtered filtrate enters a filtrate tank and then is pumped back to the production system for use through a filtrate pump, and the filter residue is conveyed to a combustion furnace through a conveyor for combustion to remove the organic substances in the filter residue.

[0006] Further, the pulverized coal adsorbs the impurities in the mother liquor, and the impurities include organic substances and salt impurities.

[0007] Further, the temperature of the mother liquor in the mixing tank is 35-100°C.

[0008] Further, the mixing tank is a stirring tank or a sedimentation tank.

[0009] Further, the pulverized coal and the mother liquor are mixed in the mixing tank, and the solid content is 5-100 g / L, and the particle size range of the pulverized coal is 1-100 μm.

[0010] Further, the mixing time of the pulverized coal and the mother liquor in the mixing tank is 1-16 hours.

[0011] Further, the filter is a vertical disk filter, a horizontal disk filter, or a pressure filter.

[0012] Further, the combustion furnace is a boiler, a rotary kiln, a carbonization furnace, an incinerator, etc.

[0013] Further, the conveyor is a belt conveyor, a pneumatic conveying device, or is transported by a vehicle to the combustion furnace area and then enters the combustion furnace.

[0014] A system for purifying mother liquor impurities for implementing the method includes a mixing tank. The mixing tank is connected to the filter by a transfer pump. The filtrate discharge end of the filter is connected to a filtrate tank. The filtrate in the filtrate tank is pumped back to the production system by a filtrate pump. The filter cake discharged from the filter is transported to the combustion furnace by a conveyor.

[0015] The beneficial effects of the present invention are as follows: The present invention uses an adsorbent as an adsorption medium for organic substances, performs adsorption in the mixing tank, conducts liquid-solid separation through a filter, sends the separated filter cake into the combustion furnace for combustion to remove organic substances after separation, returns the filtrate to the production system, has a high impurity removal efficiency, and reduces production costs. Description of the Drawings

[0016] Figure 1 is a schematic diagram of the system for purifying mother liquor impurities of the present invention In the figure: 1 - mixing tank, 2 - transfer pump, 3 - filter, 4 - filtrate tank, 5 - filtrate pump, 6 - conveyor, 7 - combustion furnace. Detailed Embodiments

[0017] For better explaining the present invention for easy understanding, the present invention will be described in detail below with reference to the drawings through specific embodiments.

[0018] Such as Figure 1As shown, the present invention provides a method and system for purifying impurities in mother liquor. The method for purifying impurities in mother liquor includes the following steps: Mix pulverized coal with the cooled mother liquor and place it in mixing tank 1. The solid content of the pulverized coal and mother liquor mixture is 5 - 100 g / L, and the particle size range of the pulverized coal is 1 - 100 μm; the temperature of the mother liquor is 35 - 100 °C. Specifically, mixing tank 1 is a stirring tank or a settling tank, and the mixing time of the pulverized coal and mother liquor in mixing tank 1 is 1 - 16 hours. After the pulverized coal adsorbs the impurities in the mother liquor, the impurities in the mother liquor adsorbed by the pulverized coal, including organic matter and salt impurities, are transported by transfer pump 2 to filter 3 for separating the adsorbed slurry. Filter 3 separates the adsorbed slurry. The filter can be a vertical disk filter, a horizontal disk filter, or a plate filter. The filtered filtrate enters filtrate tank 4 and is then sent back to the production system for utilization by filtrate pump 5. The filter residue is transported by conveyor 6 to combustion furnace 7 for combustion to remove the organic matter in the filter residue. The filter residue after filtration, i.e., the filter cake, is burned using a combustion furnace. The combustion furnace can be equipment such as a boiler, a rotary kiln, a carbonization furnace, an incinerator, or other types of combustion furnaces. The filter cake can be burned alone or mixed with other materials for combustion. Specifically, conveyor 6 is a belt conveyor, a pneumatic conveying device, or transported by vehicle to the combustion furnace area and then enters combustion furnace 7.

[0019] The present invention also provides a system for purifying impurities in mother liquor for implementing the above method, including mixing tank 1, mixing tank 1 is connected to filter 3 through transfer pump 2, the filtrate outlet end of filter 3 is connected to filtrate tank 4, the filtrate in filtrate tank 4 is sent back to the production system by filtrate pump 5, and the filter residue outlet of filter 3 is transported to combustion furnace 7 by conveyor 6.

[0020] The present invention has a high impurity purification efficiency, can reduce the impact of impurities on production, and lower production costs.

[0021] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Modifications, alterations, substitutions, and variations made by those of ordinary skill in the art to the above embodiments all fall within the scope of the present invention.

Claims

1. A method for purifying impurities in a mother liquor, characterized in that: The method comprises the following steps: coal powder is mixed with mother liquor after cooling and then placed in a mixing tank (1); after the coal powder absorbs impurities in the mother liquor, it is transported to a filter (3) through a transport pump (2) to separate the adsorbed slurry; the filtered filtrate enters a filtrate tank (4) and is then sent back to the production system for utilization through a filtrate pump (5); the filter residue is transported to a combustion furnace (7) through a conveyor (6) for combustion, thereby removing organic matter in the filter residue.

2. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The coal powder absorbs impurities in the mother liquor, and the impurities include organic matter and salt impurities.

3. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The temperature of the mother liquid in the mixing tank (1) is 35-100°C.

4. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The mixing tank (1) is a stirring tank or a sedimentation tank.

5. The method for purifying impurities in mother liquor according to claim 1, characterized in that: The coal powder is mixed with the mother liquor in the mixing tank (1), the solid content is 5-100 g / L, and the particle size of the coal powder is in the range of 1-100 μm.

6. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The mixing time of the coal powder and the mother liquor in the mixing tank (1) is 1-16 hours.

7. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The filter (3) is a vertical disc filter, a flat disc filter, or a filter press.

8. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The combustion furnace (7) is a boiler, a rotary kiln, a carbonization furnace, or an incinerator.

9. A method for purifying impurities in mother liquor according to claim 1, characterized in that: The conveyor (6) is a belt conveyor, pneumatic conveying equipment, or a car that transports the material to the combustion furnace area and then enters the combustion furnace (7).

10. A system for purifying mother liquor impurities according to any one of claims 1 to 9, characterized in that: The invention comprises a mixing tank (1), wherein the mixing tank (1) is connected to a filter (3) via a delivery pump (2), a filtrate discharge end of the filter (3) is connected to a filtrate tank (4), the filtrate of the filtrate tank (4) is sent back to the production system via a filtrate pump (5), and the filtrate discharge of the filter (3) is transported to a combustion furnace (7) via a conveyor (6).

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