Aluminum oxide online desulfurization system

Abstract

The utility model discloses an online desulfurization system for aluminum oxide, which comprises a calcium nitrate slurry preparation device, a tail gas treatment device of the preparation device and a desulfurizer adding device of the calcium nitrate slurry, the calcium nitrate slurry preparation device comprises a nitric acid storage tank and a reactor connected with the nitric acid storage tank, and the reactor is connected with an ash melting machine. A calcium nitrate slurry discharge pipe is arranged on the reactor, a PH adjusting device is arranged in the reactor, and the calcium nitrate slurry discharge pipe is sequentially connected with a finished product storage tank and a pre-desiliconization system; the tail gas treatment device comprises an exhaust pipe located on the reactor, the exhaust pipe is connected with the absorption tower, an alkali liquor adjusting opening is formed in the absorption tower, a tail gas emptying pipe is arranged at the top of the absorption tower, and a negative pressure device is arranged on the tail gas emptying pipe. According to the utility model, lime slaking residue waste on an aluminum oxide production line can be utilized for preparing an on-line desulfurizing agent in the process of producing aluminum oxide by using high-sulfur bauxite, so that the recycling of waste resources is realized, and the desulfurizing cost in the process of producing aluminum oxide by using high-sulfur bauxite is reduced.

Description

Technical Field

[0001] The utility model relates to an aluminum oxide online desulfurization system, belonging to the technical field of online desulfurization of aluminum oxide production lines. Background Art

[0002] As domestic bauxite resources are gradually depleted, the grade of bauxite ore continues to decline, and the impurity sulfur content is getting higher and higher, which has a more and more serious impact on the alumina production process. The online desulfurization technology in the alumina production process has the advantages of simple process, easy operation, no need for additional investment, and low desulfurization cost, and is widely used in the industry.

[0003] The traditional online desulfurization process in the alumina production process is sodium nitrate desulfurization, which has the disadvantages of low desulfurization limit and high desulfurization cost, and cannot achieve large-scale utilization of high-sulfur bauxite. That is, through continuous innovation and research, a more economical and efficient new online desulfurization product has been developed and applied. After industrial trials and industrial promotion and application, the desulfurization effect is better, the desulfurization limit is higher, the desulfurization cost is lower, and more importantly, the alumina production system can maintain efficient operation.

[0004] At the same time, some waste materials of the existing alumina production line are directly discarded, and it is impossible to rationally use resources, such as lime digestion ash slag, caustic slag, etc. The traditional treatment process is to transfer them to the red mud dump for storage, which occupies the red mud storage space and increases the red mud storage cost. In addition, the existing technology uses the purchase of desulfurizers and the addition of desulfurizers manually on site for desulfurization. First, the desulfurization cost is high; second, continuous addition cannot be achieved, and the desulfurization stability is poor; third, the on-site manual desulfurization operation has high safety risks and increases labor costs.

[0005] That is, there is a need for an alumina online desulfurization system that can utilize waste materials on the alumina production line to prepare desulfurizers, realize the recycling of waste resources, and reduce the desulfurization cost of the high-sulfur bauxite alumina production process. Summary of the invention

[0006] In view of this, the purpose of the utility model is to provide an online desulfurization system for alumina, which can utilize waste materials on the alumina production line to prepare desulfurizers, realize the recycling of waste resources, reduce the desulfurization cost of the high-sulfur bauxite alumina production process, and realize continuous and stable addition of desulfurizers, eliminating the safety hazards of artificial desulfurization; it can overcome the shortcomings of the existing technology.

[0007] The purpose of this utility model is achieved through the following technical solutions:

[0008] The utility model discloses an aluminum oxide online desulfurization system, which comprises a calcium nitrate slurry preparation device, a tail gas treatment device of the preparation device and a desulfurization agent adding device for desulfurization of the calcium nitrate slurry in an aluminum oxide production process. The calcium nitrate slurry preparation device comprises a nitric acid storage tank and a reactor connected with the nitric acid storage tank, the reactor is connected with an ashing machine, a raw material adding port and a calcium nitrate slurry discharge pipe are arranged on the reactor, a pH adjustment device is arranged in the reactor, the calcium nitrate slurry discharge pipe is connected with a finished product storage tank and a pre-desiliconization system in sequence; the tail gas treatment device comprises an exhaust pipe located on the upper side of the reactor, the exhaust pipe is connected with an absorption tower, an alkali liquid regulating port is arranged on the absorption tower, a tail gas exhaust pipe is arranged at the top of the absorption tower, and a negative pressure device is arranged on the tail gas exhaust pipe; the desulfurization agent adding device comprises a first tank, a secondary tank and a subsequent tank after the secondary tank arranged in the pre-desiliconization system, and the calcium nitrate slurry discharge pipe on the finished product storage tank is connected to the first tank or the secondary tank.

[0009] The pH adjusting device comprises a pH online detector, a liquid level meter and a stirring device arranged in the reactor.

[0010] The alkali solution at the alkali solution regulating port is provided by the liquid alkali, the salt-discharging sodium carbonate aqueous solution and the causticizing solution on the alumina production line.

[0011] As mentioned above, liquid pumps are provided on the pipeline between the nitric acid storage tank and the reactor and on the calcium nitrate slurry discharge pipe.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] 1. The utility model uses a calcium nitrate slurry preparation device to react the ash slag or salt-discharging sodium carbonate causticizing slag produced by the ash discharging machine in the alumina production process with nitric acid to prepare a calcium nitrate online desulfurizer slurry. At the same time, the pH value can be adjusted to be higher than 7 through a pH adjustment device, which is beneficial to subsequent desulfurization. Compared with the existing desulfurization with purchased calcium nitrate, this method can, firstly, reduce costs and help improve the operating efficiency of the enterprise. Secondly, it can realize the comprehensive recycling of the waste resources ash slag or salt-discharging sodium carbonate causticizing slag in the process of alumina production, eliminate the impact of waste resources on the environment and the problem of occupying the storage space of the red mud yard, which is beneficial to environmental protection. Thirdly, it eliminates the safety risks of artificial desulfurizer operation, saves labor costs, and can ensure the continuous and stable addition of desulfurizer to improve the desulfurization effect.

[0014] 2. The tail gas treatment device includes an exhaust pipe located on the upper side of the reactor, the exhaust pipe is connected to the absorption tower, an alkali solution regulating port is provided on the absorption tower, a tail gas exhaust pipe is provided on the top of the absorption tower, and a negative pressure device is provided on the tail gas exhaust pipe; such a structure, because nitric acid reacts in the reactor and yellow smoke is emitted, its main component is nitrogen oxides, which are treated by the absorption tower to avoid direct emission of nitrogen oxides to cause environmental pollution. The tail end of the absorption tower adopts self-priming exhaust, and the negative pressure device makes the reactor in a negative pressure state to avoid yellow smoke overflow and affect the on-site working environment. At the same time, the nitrogen oxides can be returned to the alumina production process for continued use after being absorbed by the alkali solution.

[0015] 3. The desulfurizer adding device includes a first tank, a secondary tank and a subsequent tank after the secondary tank in the pre-desiliconization system. The calcium nitrate slurry discharge pipe on the finished product storage tank is connected to the first tank or the secondary tank. A liquid pump is provided on the calcium nitrate slurry discharge pipe. With such a structure, the calcium nitrate slurry is discharged into the first tank or the secondary tank. Because the heights among the first tank, the secondary tank and the subsequent tank are continuously reduced, the calcium nitrate slurry will flow to the subsequent tank after being discharged into the first tank or the secondary tank, thereby realizing online desulfurization in the alumina production process by adding calcium nitrate slurry in the pre-desiliconization system.

[0016] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and research, or can be taught from the practice of the present invention to some extent. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings, in which:

[0018] Figure 1 It is a schematic diagram of the connection structure of the utility model.

[0019] Among them, there are a calcium nitrate slurry preparation device 1; a nitric acid storage tank 1-1; a reactor 1-2; an ash machine 1-3; a finished product storage tank 1-4; an exhaust gas treatment device 2; an absorption tower 2-1; an alkali solution regulating port 2-2; an exhaust gas exhaust pipe 2-3; a desulfurizer adding device 3; a first tank 3-1; a secondary tank 3-2; and a subsequent tank 3-3. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention, rather than for limiting the protection scope of the present invention.

[0021] like Figure 1As shown, the utility model discloses an online desulfurization system for aluminum oxide, which comprises a calcium nitrate slurry preparation device 1, an exhaust gas treatment device 2 of the preparation device and a desulfurization agent adding device 3 for desulfurization of calcium nitrate slurry in an aluminum oxide production process. The calcium nitrate slurry preparation device 1 comprises a nitric acid storage tank 1-1 and a reactor 1-2 connected to the nitric acid storage tank 1-1; nitric acid in the nitric acid storage tank 1-1 is regularly added by a tank truck, the reactor 1-2 is a reaction tank, the reactor 1-2 is connected to a ash machine 1-3, a raw material adding port and a calcium nitrate slurry discharge pipe are arranged on the reactor 1-2, wherein the raw material adding port is connected to the nitric acid storage tank 1-1, and the nitric acid in the nitric acid storage tank 1-1 is regularly added by a tank truck, the reactor 1-2 is a reaction tank, and the reactor 1-2 is connected to a ash machine 1-3, and ... and the raw material adding port is connected to the nitric acid storage tank 1-1, and the raw material adding port is connected to the nitric acid storage tank 1-1, and the raw material adding port is connected to the nitric acid storage tank 1-1, and the raw material adding port is connected to the nitric acid storage tank 1-1, and the raw material adding port is connected to the nitric The opening is provided with a sealed door that can be opened and closed, which is conducive to preventing the yellow smoke generated by nitric acid during the preparation process from escaping; a pH adjustment device is provided in the reactor 1-2, and the calcium nitrate slurry discharge pipe is connected to the finished product storage tank 1-4 and the pre-desiliconization system in turn; the pH adjustment device includes a pH online detector, a liquid level meter and a stirring device provided in the reactor 1-2; such a calcium nitrate slurry preparation device 1 reacts the ash slag produced by the ash machine 1-3 with nitric acid to prepare a calcium nitrate online desulfurizer slurry, and at the same time, through the pH adjustment device, the pH value can be adjusted to be higher than 7, which is conducive to subsequent desulfurization. Compared with the existing desulfurization of purchased calcium nitrate, this method can, firstly, reduce costs and help improve the operating efficiency of the enterprise. Secondly, it can realize the comprehensive recycling of waste resources ash slag or salt caustic slag in the process of alumina production, eliminate the impact of waste resources on the environment and the problem of occupying the storage space of the red mud yard, which is beneficial to environmental protection. Thirdly, it eliminates the safety risks of artificial desulfurizer operation, saves labor costs, and can ensure the continuous and stable addition of desulfurizer to improve the desulfurization effect.

[0022] The tail gas treatment device 2 includes an exhaust pipe located on the upper side of the reactor 1-2, the exhaust pipe is connected to the absorption tower 2-1, an alkali solution regulating port 2-2 is provided on the absorption tower 2-1, a tail gas exhaust pipe 2-3 is provided on the top of the absorption tower 2-1, and a negative pressure device is provided on the tail gas exhaust pipe 2-3; such a structure, because nitric acid reacts in the reactor and yellow smoke is emitted, its main component is nitrogen oxides, which are processed by the absorption tower to avoid direct emission of nitrogen oxides to cause environmental pollution, the tail end of the absorption tower adopts self-priming exhaust, and the negative pressure device makes the reactor in a negative pressure state to avoid yellow smoke overflow and affect the on-site working environment. At the same time, the nitrogen oxides can be returned to the alumina production process for continued use after being absorbed by the alkali solution.

[0023] The desulfurizing agent adding device 3 comprises a first tank 3-1, a secondary tank 3-2 and a subsequent tank 3-3 after the secondary tank 3-2, which are provided in the pre-desiliconization system; the calcium nitrate slurry discharge pipe on the finished product storage tank 1-4 is connected to the first tank 3-1 or the secondary tank 3-2; the alkali solution at the alkali solution regulating port 2-2 is provided by the liquid alkali, the sodium carbonate aqueous solution for salt removal, the causticizing liquid, etc. on the alumina production line, and a liquid pump is provided on the pipeline between the nitric acid storage tank 1-1 and the reactor 1-2 and on the calcium nitrate slurry discharge pipe; such a structure, by discharging the calcium nitrate slurry into the first tank 3-1 or the secondary tank 3-2, because the height between the first tank 3-1, the secondary tank 3-2 and the subsequent tank 3-3 is continuously reduced, the calcium nitrate slurry is discharged into the first tank 3-1 or the secondary tank 3-2, and then flows to the subsequent tank 3-3, thereby realizing online desulfurization by calcium nitrate slurry in the pre-desiliconization system.

[0024] After many tests, the device has increased the sulfur content limit of the ore by more than 40%, and the annual consumption of high-sulfur ore can reach more than 1 million tons, realizing the large-scale utilization of high-sulfur ore, which has a good industrial application prospect. It is planned to use the waste resources in the alumina production process to prepare a new desulfurizer to further reduce the desulfurization cost and better realize the large-scale on-site transformation and application of high-sulfur ore resources. At the same time, the on-site manual desulfurization operation is cancelled, the safety risk is reduced, and the desulfurization loading and unloading costs and labor costs are reduced.

[0025] The above is only a preferred embodiment of the utility model, and does not limit the confidentiality of the utility model in any form. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still falls within the scope of the technical solution of the utility model.

Claims

1. An alumina online desulfurization system, characterized in that: The invention comprises a calcium nitrate slurry preparation device (1), an exhaust gas treatment device (2) of the preparation device, and a desulfurization agent adding device (3) for using the calcium nitrate slurry for desulfurization in an alumina production process. The calcium nitrate slurry preparation device (1) comprises a nitric acid storage tank (1-1) and a reactor (1-2) connected to the nitric acid storage tank (1-1), the reactor (1-2) is connected to an ashing machine (1-3), a raw material adding port and a calcium nitrate slurry discharge pipe are provided on the reactor (1-2), a pH adjustment device is provided in the reactor (1-2), and the calcium nitrate slurry discharge pipe is connected to a finished product storage tank (1-4) and a pre-desiliconization system in sequence; The tail gas treatment device (2) comprises an exhaust pipe located on the upper side of the reactor (1-2), the exhaust pipe is connected to the absorption tower (2-1), an alkali liquid regulating port (2-2) is provided on the absorption tower (2-1), a tail gas exhaust pipe (2-3) is provided on the top of the absorption tower (2-1), and a negative pressure device is provided on the tail gas exhaust pipe (2-3); the desulfurization agent adding device (3) comprises a first tank (3-1), a secondary tank (3-2) and a subsequent tank (3-3) after the secondary tank (3-2) provided in the pre-desiliconization system, and the calcium nitrate slurry discharge pipe on the finished product storage tank (1-4) is connected to the first tank (3-1) or the secondary tank (3-2).

2. The alumina online desulfurization system according to claim 1, characterized in that: The pH adjustment device comprises a pH online detector, a liquid level meter and a stirring device arranged in the reactor (1-2).

3. The alumina online desulfurization system according to claim 1, characterized in that: The alkali solution at the alkali solution regulating port (2-2) is provided by the liquid alkali, the salt-discharging sodium carbonate aqueous solution and the causticizing solution on the alumina production line.

4. The alumina online desulfurization system according to any one of claims 1 to 3, characterized in that: Liquid pumps are provided on the pipeline between the nitric acid storage tank (1-1) and the reactor (1-2) and on the calcium nitrate slurry discharge pipe.

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