Magnesium smelting crystallizer with assisted main and auxiliary crystals and crystallization method of magnesium smelting crystallizer

Abstract

The invention belongs to the technical field of magnesium smelting equipment, and discloses a main and auxiliary crystallization-assisted magnesium smelting crystallizer and a crystallization method thereof.The main and auxiliary crystallization-assisted magnesium smelting crystallizer comprises a barrel body with the upper end and the lower end open, one or more external branch barrels are arranged on the barrel body and communicate with the barrel body, a main crystallization device is installed at the upper end of the barrel body, and a secondary crystallization device is installed at the lower end of the barrel body; an auxiliary crystallization device is mounted at the tail end of the branch cylinder; the main crystallization device and the auxiliary crystallization device are matched with each other to realize fine control on magnesium steam crystallization, the vertical tank is vacuumized before magnesium reduction reaction, and airflow only passes through the auxiliary crystallization barrel of the auxiliary crystallization device at the initial stage of the reduction reaction, so that the pollution to the main crystallization barrel is avoided, and the production efficiency is improved. And a precondition is provided for crystallizing high-purity magnesium crystals in the main crystallization cylinder.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnesium smelting equipment, and in particular relates to a magnesium smelting crystallizer with primary and secondary crystallization complementing each other and a crystallization method thereof. Background Art

[0002] As a mainstream magnesium smelting process, silicothermic magnesium smelting consists of three core steps: calcination, reduction, and refining, ultimately producing crude magnesium. With technological advancements, the vertical magnesium smelting process, with its significant advantages, has gradually replaced the traditional horizontal tank process, becoming the main direction of technological development in the industry. The core improvements of this process are reflected in its unique vertical tank structure design and supporting process system.

[0003] The core equipment of the vertical magnesium smelting process is the vertical tank. This equipment adopts a segmented structural design, consisting of an upper condensation and crystallization section, a middle vertical tank reduction reaction section, and a lower slag discharge section. Each section is connected by flange fastening or welding to achieve airtight connection, forming a complete and sealed reaction chamber. The condensation and crystallization section integrates a magnesium crystallizer as a core functional component, and the outer wall of the reduction reaction section is equipped with a dedicated reduction furnace heating system. The internal pressure of the tank is maintained by a vacuum pump system.

[0004] In the process of process implementation, when magnesium raw material generation reduction reaction generates magnesium vapor in the vertical tank, this magnesium vapor rises to the condensation crystallization section under the effect of temperature gradient, forms thick magnesium after directional cooling. In magnesium vapor, be mixed with a small amount of active metallic impurities, such as sodium, potassium, etc., can be mixed among the thick magnesium in the reduction reaction initial stage, because the chemical property of sodium, potassium, etc. is very active, easily oxidized in air, meet water meeting violent reaction and emit hydrogen, release a large amount of heat simultaneously, the hydrogen energy produced can be ignited, after thick magnesium is taken out from the vertical tank, the potassium, sodium that property is more active meet air, can burn up rapidly. If can not be extinguished in time with covering agent, will further ignite thick magnesium (particularly the thick magnesium of crystallization is not dense), so both cause the burning loss of thick magnesium, pollute the production environment again. On the other hand, contain more metallic impurities in the reduction reaction initial stage magnesium vapor, when passing through magnesium crystallizer, it is polluted and also can continue to pollute crystallization magnesium and cause the impurity content of metallic magnesium to rise, obviously affects the crystallization purity of magnesium. Summary of the Invention

[0005] The purpose of the present invention is to solve the technical problems existing in the prior art and to propose a magnesium smelting crystallizer with primary and secondary crystallization and a crystallization method thereof; the technical solution adopted to achieve the above purpose is:

[0006] A magnesium smelting crystallizer with complementary primary and secondary crystallization, comprising a barrel body with open upper and lower ends, one or more external branch barrels provided on the barrel body, the branch barrels being connected to the barrel body, a primary crystallization device installed at the upper end of the barrel body, and a secondary crystallization device installed at the end of the branch barrel;

[0007] The main crystallization device includes a main cooling water jacket coaxially installed at the upper end of the cylinder body. A main crystallization end cover is installed at the end of the main cooling water jacket. A main crystallization cylinder is fixed inside the main cooling water jacket. A main water outlet pipeline and a main water inlet pipeline are provided on the main cooling water jacket. A main vacuum pumping pipeline communicating with the inside of the cylinder body is provided on the main cooling water jacket;

[0008] The secondary crystallization device includes a secondary cooling water jacket coaxially installed at the end of the branch cylinder. A secondary crystallization end cover is installed at the end of the secondary cooling water jacket. A secondary crystallization cylinder is fixed inside the secondary cooling water jacket. A secondary water outlet pipeline and a secondary water inlet pipeline are provided on the secondary cooling water jacket. A secondary vacuum pumping pipeline communicating with the inside of the cylinder body is provided on the secondary cooling water jacket;

[0009] Preferably, the length and inner diameter of the main crystallization cylinder are greater than those of the secondary crystallization cylinder, and the heat radiation area between the main crystallization cylinder and the main cooling water jacket is greater than the heat radiation area between the secondary crystallization cylinder and the secondary cooling water jacket.

[0010] Preferably, an annular pressing cylinder for pressing the secondary crystallization cylinder is provided at the bottom of the secondary crystallization end cover. Hollow openings are provided on the wall of the annular pressing cylinder. A support for supporting the secondary crystallization cylinder is provided inside the secondary cooling water jacket.

[0011] Preferably, a vacuum-breaking air inlet pipeline is provided on the cylinder body. A control valve is installed on the vacuum-breaking air inlet pipeline, and the vacuum-breaking air inlet pipeline is connected to an inert gas source.

[0012] A magnesium crystallization method using the main and secondary crystallization-assisted magnesium smelting crystallizer as described above includes the following steps:

[0013] Step A: Sealingly install the magnesium smelting crystallizer on the top of the magnesium reduction vertical tank, corresponding to install the main crystallization cylinder and the secondary crystallization cylinder, and seal each port through the main crystallization end cover and the secondary crystallization end cover.

[0014] Step B: Open and control the circulating water volume of one of the secondary cooling water jackets, open the control valve of the secondary vacuum pumping pipeline to evacuate the inside of the vertical tank, and close the control valve of the main vacuum pumping pipeline. At this time, the powder and a small amount of magnesium metal vapor in the early stage in the tank enter the secondary crystallization cylinder to start crystallization;

[0015] Step C: When the absolute pressure inside the vertical tank reaches about 1000 - 5000 Pa and the temperature of the magnesium raw material pellets inside the vertical tank rises to about 1080 - 1190 °C, a large amount of magnesium vapor is reduced from the magnesium raw material pellets. At this time, reduce the circulating water volume of the secondary cooling water jacket and close the secondary vacuum pumping pipeline; open the circulating water volume of the main cooling water jacket and open the control valve of the main vacuum pumping pipeline, and a large amount of magnesium vapor enters the main crystallization cylinder to start crystallization;

[0016] Step D: After the magnesium reduction is completed, close all control valves of the main vacuum pipeline and the auxiliary vacuum pipeline, open the control valve of the vacuum-breaking intake pipeline to break the vacuum until normal pressure, and then open the main crystallization end cover and the auxiliary crystallization end cover to discharge magnesium and slag.

[0017] Preferably, three external branch cylinders are provided on the cylinder body, and an auxiliary crystallization device is installed at the end of each branch cylinder. In step C, according to the change in the amount of magnesium vapor generated, appropriately control the number of working auxiliary magnesium crystallization devices.

[0018] The beneficial effects of the present invention are as follows: (1) Fine control of the crystallization of magnesium vapor is achieved through the mutual cooperation of the main crystallization device and the auxiliary crystallization device.

[0019] (2) Before the magnesium reduction reaction, the vertical tank is evacuated, and in the initial stage of the reduction reaction, the gas flow only passes through the auxiliary crystallization cylinder of the auxiliary crystallization device, avoiding contamination of the main crystallization cylinder and providing a prerequisite for crystallizing high-purity magnesium crystals in the main crystallization cylinder.

[0020] (3) Separate control of the initial stage and the middle and later stages of magnesium reduction is achieved, enabling the separation of the initially formed crude magnesium crystals with impurities and the high-purity magnesium crystals during the reduction stage in the vertical tank. The high-purity magnesium crystals are spared from refining, shortening the process and reducing the number of processes.

[0021] (4) Ensures the purity of the crystallized magnesium in the main crystallizer in the later stage of the reduction reaction; also avoids the ignition of crude magnesium by potassium and sodium, resulting in the loss of crude magnesium, improves the production environment. Through reasonable temperature control, vacuum degree control and their coordination, metal impurities such as potassium and sodium crystallize in the auxiliary crystallization cylinder. The auxiliary crystallization cylinder is small in volume and easy to extinguish fires. At the same time, even if the fire extinguishing is not timely, the burned loss is the relatively poor-quality crude magnesium crystallized in the early stage. Description of the Drawings

[0022] Figure 1 is one of the structural schematic diagrams of the present invention;

[0023] Figure 2 is the schematic diagram of the crystallization process of the present invention;

[0024] Figure 3 is one of the structural schematic diagrams of the invention. Detailed Embodiments

[0025] The present invention will be further described below with reference to the drawings. Specific Embodiment 1:

[0027] As Figure 1As shown in the figure, a magnesium smelting crystallizer with complementary main and auxiliary crystallization includes a cylindrical body 1 with open upper and lower ends. An external branch cylinder 3 is provided on the cylindrical body 1, and the branch cylinder 3 is communicated with the cylindrical body 1. A main crystallization device A is installed at the upper end of the cylindrical body 1, and an auxiliary crystallization device B is installed at the end of the branch cylinder 3;

[0028] The main crystallization device A includes a main cooling water jacket A3 coaxially installed at the upper end of the cylindrical body 1. A main crystallization end cover A7 is installed at the end of the main cooling water jacket A3. A main crystallization cylinder A2 is fixed in the main cooling water jacket A3. A main water outlet pipeline A8 and a main water inlet pipeline A10 are provided on the main cooling water jacket A3. A main vacuum extraction pipeline A6 communicating with the inside of the cylindrical body 1 is provided on the main cooling water jacket A8;

[0029] The auxiliary crystallization device B includes an auxiliary cooling water jacket B11 coaxially installed at the end of the branch cylinder 3. An auxiliary crystallization end cover B8 is installed at the end of the auxiliary cooling water jacket B11. An auxiliary crystallization cylinder B10 is fixed in the auxiliary cooling water jacket B10. An auxiliary water outlet pipeline B4 and an auxiliary water inlet pipeline B7 are provided on the auxiliary cooling water jacket B10. An auxiliary vacuum extraction pipeline B1 communicating with the inside of the cylindrical body 1 is provided on the auxiliary cooling water jacket B10;

[0030] Control valves A9 and A11 are respectively installed on the main water outlet pipeline A8 and the main water inlet pipeline A10. A control valve A5 is installed on the main vacuum extraction pipeline A6. A vacuum pump A4 is connected to the end of the main vacuum extraction pipeline A6; Control valves B5 and B6 are respectively installed on the auxiliary water outlet pipeline B4 and the auxiliary water inlet pipeline B7. A control valve B2 is installed on the auxiliary vacuum extraction pipeline B1. A vacuum pump B3 is connected to the end of the auxiliary vacuum extraction pipeline B1.

[0031] The length and inner diameter of the main crystallization cylinder A2 are larger than those of the auxiliary crystallization cylinder B10. The heat radiation area between the main crystallization cylinder A2 and the main cooling water jacket A3 is larger than the heat radiation area between the auxiliary crystallization cylinder B10 and the auxiliary cooling water jacket B10. The crystallization area of the main crystallization cylinder A2 is 5 - 10 times that of the auxiliary crystallization cylinder B10.

[0032] A vacuum-breaking air inlet pipeline 2 is provided on the cylindrical body 1. A control valve is installed on the vacuum-breaking air inlet pipeline 2, and the vacuum-breaking air inlet pipeline 2 is connected to an inert gas source;

[0033] In order to, an annular pressing cylinder B13 for pressing the auxiliary crystallization cylinder B10 is provided at the bottom of the auxiliary crystallization end cover B8. Hollow holes are provided on the wall of the annular pressing cylinder B13. A support B9 for supporting the auxiliary crystallization cylinder B10 is provided in the auxiliary cooling water jacket B11. Thus, it further ensures that the auxiliary crystallization end cover B8 is tightly pressed on the support seat, thereby preventing magnesium vapor in the cylindrical body 1 from entering the outside of the auxiliary crystallization end cover B8.

[0034] The component test results in the main crystallization cylinder and the auxiliary crystallization cylinder are as follows:

[0035] Main crystallization cylinder

[0036]

[0037] Auxiliary crystallization cylinder

[0038] Specific Embodiment 2:

[0040] As Figure 3 shown, on the basis of Specific Embodiment 1, two or three external branch cylinders 3 can be circumferentially arranged around the cylinder body 1, and auxiliary crystallization devices B are installed at the ends of the branch cylinders 3. Specific Embodiment 3:

[0042] As Figure 2 shown, a magnesium crystallization method using the main and auxiliary crystallization complementary magnesium smelting crystallizer as described above includes the following steps:

[0043] Step A: Sealingly install the magnesium smelting crystallizer on the top of the magnesium reduction vertical tank 6, correspondingly install the main crystallization cylinder A2 and the auxiliary crystallization cylinder B10, and seal each port through the main crystallization end cover A74 and the auxiliary crystallization end cover B8.

[0044] Step B: While the reduction furnace 7 continuously heats the vertical tank 6, take a certain amount of magnesium raw material pellets 4 into the accommodation chamber between the vertical tank 6 and the central cylinder 5 according to production needs. There are evenly distributed ventilation holes on the wall of the central cylinder 5. At this time, open and control the circulating water volume of one of the auxiliary cooling water jackets B10, open the control valve B2 of the auxiliary vacuum pumping pipeline B1 to pump the vacuum in the vertical tank 6, and close the control valve A5 of the main vacuum pumping pipeline A6. At this time, the powder in the vertical tank 6 and the previous trace amount of magnesium metal vapor, etc. enter the auxiliary crystallization cylinder B10 to start crystallization to form the coarse magnesium crystal B12;

[0045] Step C: When the absolute pressure in the vertical tank 6 reaches about 1000 - 5000 Pa and the temperature of the magnesium raw material pellets 4 in the vertical tank 6 rises to about 1080 - 1190 °C, a large amount of magnesium vapor is reduced from the magnesium raw material pellets 4. At this time, reduce the circulating water volume of the auxiliary cooling water jacket B10, and close the control valve B2 of the auxiliary vacuum pumping pipeline B1; open the circulating water volume of the main cooling water jacket A2, and open the control valve A5 of the main vacuum pumping pipeline A6. A large amount of magnesium vapor enters the main crystallization cylinder A2 to start crystallization to form the pure magnesium crystal A1;

[0046] Step D: After the magnesium reduction is completed, close all control valves A5 and B2 of the main vacuum extraction pipeline A6 and the auxiliary vacuum extraction pipeline B1, open the control valve of the vacuum-breaking intake pipeline 2 to break the vacuum until normal pressure, and open the main crystallization end cover A74 and the auxiliary crystallization end cover B8 to discharge magnesium and slag. Specific Embodiment 4:

[0048] On the basis of Specific Embodiment 3, three external branch cylinders 3 are provided on the cylinder body 1, and an auxiliary crystallization device B is installed at the end of each branch cylinder 3. In Step C, according to the change in the amount of magnesium vapor generated, appropriately control the number of auxiliary magnesium crystallization devices B in operation.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the present invention in each embodiment.

Claims

1. A magnesium smelting crystallizer with complementary main and secondary crystallization, characterized in that, It includes a cylindrical body with open upper and lower ends, and one or more external branch cylinders are provided on the cylindrical body. The branch cylinders are communicated with the cylindrical body. A main crystallization device is installed at the upper end of the cylindrical body, and an auxiliary crystallization device is installed at the end of the branch cylinder. The main crystallization device includes a main cooling water jacket coaxially installed at the upper end of the cylindrical body. A main crystallization end cover is installed at the end of the main cooling water jacket. A main crystallization cylinder is fixed in the main cooling water jacket. A main water outlet pipeline and a main water inlet pipeline are provided on the main cooling water jacket. A main vacuum extraction pipeline communicated with the inside of the cylindrical body is provided on the main cooling water jacket. The auxiliary crystallization device includes an auxiliary cooling water jacket coaxially installed at the end of the branch cylinder. An auxiliary crystallization end cover is installed at the end of the auxiliary cooling water jacket. An auxiliary crystallization cylinder is fixed in the auxiliary cooling water jacket. An auxiliary water outlet pipeline and an auxiliary water inlet pipeline are provided on the auxiliary cooling water jacket. An auxiliary vacuum extraction pipeline communicated with the inside of the cylindrical body is provided on the auxiliary cooling water jacket.

2. The magnesium smelting crystallizer with complementary main and secondary crystallization according to claim 1, characterized in that The length and inner diameter of the main crystallization cylinder are larger than those of the auxiliary crystallization cylinder, and the heat radiation area between the main crystallization cylinder and the main cooling water jacket is larger than the heat radiation area between the auxiliary crystallization cylinder and the auxiliary cooling water jacket.

3. The magnesium smelting crystallizer with main and auxiliary crystallization complementarity according to claim 1, characterized in that, An annular pressing cylinder for pressing the auxiliary crystallization cylinder is provided at the bottom of the auxiliary crystallization end cover. A hollow is provided on the wall of the annular pressing cylinder. A support for supporting the auxiliary crystallization cylinder is provided in the auxiliary cooling water jacket.

4. The magnesium smelting crystallizer with complementary main and auxiliary crystallization according to any one of claims 1 to 3, characterized in that A vacuum-breaking air inlet pipeline is provided on the cylindrical body. A control valve is installed on the vacuum-breaking air inlet pipeline, and the vacuum-breaking air inlet pipeline is connected to an inert gas source.

5. A magnesium crystallization method using the magnesium crystallization device with complementary primary and secondary crystallization as described above, characterized in that, It includes the following steps: Step A: Sealingly install the magnesium smelting crystallizer on the top of the magnesium reduction vertical tank, correspondingly install the main crystallization cylinder and the auxiliary crystallization cylinder, and seal each port through the main crystallization end cover and the auxiliary crystallization end cover. Step B: Start and control the circulating water volume of one of the auxiliary cooling water jackets, open the control valve of the auxiliary vacuum extraction pipeline to evacuate the inside of the vertical tank, and close the control valve of the main vacuum extraction pipeline. At this time, the powder in the tank and a small amount of magnesium metal vapor in the early stage enter the auxiliary crystallization cylinder to start crystallization. Step C: When the absolute pressure in the vertical tank reaches about 1000 - 5000 Pa and the temperature of the magnesium raw material pellets in the vertical tank rises to about 1080 - 1190 °C, a large amount of magnesium vapor is reduced from the magnesium raw material pellets. At this time, reduce the circulating water volume of the auxiliary cooling water jacket and close the auxiliary vacuum extraction pipeline; start the circulating water volume of the main cooling water jacket and open the control valve of the main vacuum extraction pipeline. A large amount of magnesium vapor enters the main crystallization cylinder to start crystallization. Step D: After the magnesium reduction is completed, close all the control valves of the main vacuum extraction pipeline and the auxiliary vacuum extraction pipeline, open the control valve of the vacuum-breaking air inlet pipeline to break the vacuum until normal pressure, and open the main crystallization end cover and the auxiliary crystallization end cover to discharge magnesium and slag.

6. The magnesium crystallization method according to claim 5, characterized in that, Three external branch cylinders are provided on the cylindrical body, and an auxiliary crystallization device is installed at the end of each branch cylinder. In step C, appropriately control the number of working auxiliary magnesium crystallization devices according to the change in the amount of magnesium vapor generated.

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