A deep-bed filtration and purification process for molten aluminum alloy

Abstract

This invention relates to the field of aluminum molten metal purification, specifically to a deep-bed filtration purification process for aluminum alloy casting molten metal. This process solves the problem of low efficiency caused by cleaning in current aluminum alloy casting molten metal processes. The process includes the following steps: a) Aluminum alloy raw materials are added to a furnace and heated to melt, forming molten aluminum. An alkali remover is added, and the molten aluminum is filtered through permeable bricks at the bottom of the furnace for deep-bed filtration. After a primary filtration to remove slag, primary purification is achieved; b) The molten aluminum obtained in step a is transferred to a holding furnace and degassed and refined using a purification device, resulting in secondary purification; c) The molten aluminum obtained in step b is subjected to secondary filtration to remove slag. The purification device is located above the holding furnace and includes a frame, a hollow rotating rod that is height-adjustable on the frame for rotary blowing degaussing, and a slag removal mechanism. A rotating motor is driven to the hollow rotating rod, and a gas supply pipe for inert gas delivery is connected to the hollow rotating rod.

Description

Technical Field

[0001] This invention relates to the field of aluminum liquid purification and treatment, specifically to a deep-bed filtration and purification process for aluminum alloy casting liquid. Background Technology

[0002] In the production of cast aluminum alloy materials, to ensure product quality, an important step in the processing is to purify the molten aluminum to remove internal impurities such as hydrogen, non-metallic, and metallic impurities. The specific purification process is illustrated in the technical solution with authorization announcement number CN 101760634 B, a four-stage composite purification method for cast aluminum alloy wheel hubs, characterized by the following purification steps:

[0003] Primary purification: By blowing nitrogen into the furnace and adding highly efficient active flux for composite refining, gas and non-metallic inclusions in the aluminum alloy melt are removed;

[0004] Secondary purification: A foam ceramic filter screen is installed at the outlet of the furnace to filter and remove slag from the outflowing molten aluminum alloy;

[0005] Three-stage purification: Nitrogen gas is blown into the tundish to remove the gas from the molten aluminum alloy inside the tundish;

[0006] Level 4 purification: Nitrogen is blown into the casting holding furnace to remove hydrogen from the molten aluminum alloy, and refining agents and slag removers are added to the furnace for further refining and slag removal.

[0007] In the fourth-stage purification process, after adding refining agents and slag removers into the holding furnace, the holding furnace needs to be cleaned after refining and slag removal. This process greatly affects production efficiency. Summary of the Invention

[0008] Therefore, the present invention provides a deep bed filtration and purification process for aluminum alloy casting liquid, which solves the problem of low efficiency caused by cleaning in current aluminum alloy casting liquid.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] A deep-bed filtration and purification process for molten aluminum alloy includes the following steps:

[0011] a. The aluminum alloy raw material is put into the furnace and heated to melt it into aluminum liquid. An alkali removal agent is added and the liquid is filtered through the permeable bricks at the bottom of the furnace. After that, it is filtered to remove slag, thus achieving a purification process.

[0012] b. Transfer the aluminum liquid obtained in step a into a holding furnace and degas and refine it through a purification device to form a secondary purification process.

[0013] c. Perform secondary filtration to remove slag from the aluminum liquid obtained in step b;

[0014] The purification device is located above the heat preservation furnace and includes a frame, a hollow rotating rod that can be lifted and mounted on the frame for rotary blowing and degassing, and a cleaning mechanism for removing impurities. A rotating motor that drives the hollow rotating rod to rotate is connected to the hollow rotating rod, and a gas delivery pipe for conveying inert gas is connected to the hollow rotating rod.

[0015] The impurity removal mechanism includes a support that can move up and down with the hollow rotating bar, a horizontal shaft located at the lower end of the support and arranged radially along the hollow rotating bar, and a number of fan blades arranged on the horizontal shaft for picking up impurities. A horizontal shaft motor is driven to rotate the horizontal shaft to drive the fan blades to move. A support motor and its transmission components are driven to rotate the support around the hollow rotating bar.

[0016] Preferably, the air supply pipe is connected to a feeder for adding impurity removal agent.

[0017] Preferably, the hollow rotating rod includes a rod body and a disc located at the bottom end of the rod body. Air channels are formed in the rod body and the disc. The bottom of the disc body is a frustum structure, and air holes are evenly distributed on the conical surface of the frustum structure.

[0018] Preferably, the rod body has a radially extending outlet for discharging the impurity remover, and the air passage has a guide groove for guiding the impurity remover to the outlet.

[0019] Preferably, the fan blade is spiral-shaped, and a housing is fitted over the fan blade. A material collection tank is provided on the housing located at the output end of the fan blade.

[0020] Preferably, the primary filtration and secondary filtration for slag removal use foam ceramic filter plates with a mesh size of 30 and 50 mesh, respectively.

[0021] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0022] This technical solution utilizes a purification device equipped with a purification mechanism. During operation, the purification mechanism simultaneously removes impurities during the degassing process. Impurities generated during degassing are collected by the blades of the purification mechanism as they rise with the inert gas. Furthermore, during operation, the horizontal axis with the blades rotates within the holding furnace around a hollow rotating rod, thus covering the entire surface of the molten aluminum and ensuring effective impurity removal. This structure significantly increases the cleaning interval of the holding furnace and avoids the large accumulation of impurities at the bottom of the holding furnace as in traditional structures, thereby reducing the frequency of cleaning and ensuring production efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the purification device according to Embodiment 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the horizontal axis in Embodiment 1 of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of the hollow rotating rod in Embodiment 1 of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the horizontal axis in Embodiment 2 of the present invention.

[0027] Reference numerals: 100, frame; 101, rotating motor; 102, air supply pipe; 1, hollow rotating rod; 1a, rod body; 1b, disc body; 11, air passage; 12, air hole; 13, discharge port; 14, guide trough; 2, support; 21, support motor; 22, transmission assembly; 3, horizontal shaft; 31, fan blade; 311, collection trough; 32, shell; 33, material tank; 4, feeder. Detailed Implementation

[0028] The following will describe in detail the implementation of the present invention with reference to specific embodiments, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0029] Example 1

[0030] refer to Figures 1 to 3 A deep-bed filtration and purification process for molten aluminum alloy includes the following steps:

[0031] a. The aluminum alloy raw material is put into the furnace and heated to melt it into aluminum liquid. An alkali removal agent is added and the liquid is filtered through the permeable bricks at the bottom of the furnace. After that, it is filtered to remove slag, thus achieving a purification process.

[0032] b. Transfer the aluminum liquid obtained in step a into a holding furnace and degas and refine it through a purification device to form a secondary purification process.

[0033] c. The aluminum liquid obtained in step b undergoes secondary filtration to remove slag. In the above process, both step a (deep bed filtration) and step c (secondary filtration) involve filtration and slag removal using foam ceramic filter plates to remove impurities. This process involves the transfer of aluminum liquid, thus not affecting the efficiency of subsequent rotary jet degassing. Furthermore, the primary and secondary filtration slag removal uses 30-mesh and 50-mesh foam ceramic filter plates respectively, achieving two-stage filtration from large to small particles. During degassing in the purification device, to ensure production... The continuity of the heat preservation furnace needs to be considered, so the amount of impurities that the furnace can bear needs to be taken into account. Therefore, in the design, the purification device is located above the heat preservation furnace and includes a frame 100, a hollow rotating rod 1 that can be lifted and lowered on the frame 100 for rotary blowing and degassing, and a degassing mechanism for removing impurities. A rotating motor 101 that drives the hollow rotating rod 1 to rotate is connected to the hollow rotating rod 1. An inert gas delivery pipe 102 is connected to the hollow rotating rod 1 for delivering gas through a rotating structure.

[0034] The impurity removal mechanism includes a support 2 that can move up and down with the hollow rotating rod 1, a horizontal shaft 3 located at the lower end of the support 2 and arranged radially along the hollow rotating rod 1, and several fan blades 31 arranged on the horizontal shaft 3 for picking up impurities. Collection troughs 311 are arranged on the fan blades 31 to collect the material. A motor (not shown in the figure) is driven to rotate the horizontal shaft 3 to drive the fan blades 31. A support motor 21 and its transmission assembly 22 are driven to rotate the support 2 around the hollow rotating rod 1. The transmission assembly 22 consists of a ring-shaped gear and a cooperating transmission gear. In use, the support motor 21 drives the ring-shaped gear to rotate, thereby achieving the rotation of the entire support 2 and thus the rotation of the horizontal shaft 3. Correspondingly, the frame 100 is equipped with... The hollow rotating rod 1 and the impurity removal mechanism are raised and lowered by a lifting mechanism (not shown in the figure), such as a motor for lifting and corresponding guide rail components. This technical solution uses a purification device with an impurity removal mechanism to simultaneously remove impurities during the degassing and purification process. Impurities generated during the degassing process are collected by the fan blades 31 of the impurity removal mechanism as they float upward with the inert gas. Furthermore, during operation, the horizontal shaft 3 equipped with the fan blades 31 rotates around the hollow rotating rod 1 inside the holding furnace, thereby covering the entire surface of the aluminum liquid and ensuring the impurity removal effect. This structure can greatly increase the cleaning interval of the holding furnace and avoid the large accumulation of impurities at the bottom of the holding furnace under the traditional structure, thereby reducing the cleaning frequency and ensuring production efficiency.

[0035] Structurally, the gas supply pipe 102 is connected to a feeder 4 for adding impurity removal agents. These impurity removal agents include refining agents and slag removers used in refining processes, all of which can be added through the feeder 4. The feeder 4 is a quantitative feeding structure, adding materials uniformly by controlling the feeding amount per unit time, and then introducing inert gas into the molten aluminum through the gas supply pipe 102. Correspondingly, the hollow rotating rod 1 includes a rod body 1a and a disc body 1b located at the bottom of the rod body 1a. Gas channels 11 are formed within the rod body 1a and the disc body 1b. The bottom of the disc body 1b has a frustum-shaped structure, with air holes 12 evenly distributed on the conical surface. The inert gas is discharged through the air holes 12 on the disc body 1b and is rotated and sprayed as the hollow rotating rod 1 rotates, achieving more uniform degassing and purification. The inert gas can be nitrogen or argon, etc. The fabric structure allows the ejected inert gas to first descend and then slowly rise, ensuring it reaches the bottom of the holding furnace for degassing and also adsorbing oxide inclusions in the molten aluminum at the bottom. Simultaneously, the rod 1a has a radially extending outlet 13 for discharging the degassing agent, and the air passage 11 has a guide trough 14 for guiding the degassing agent to the outlet 13. Correspondingly, the outlet 13, being connected to the air supply pipe 102, also has a certain blowing effect. Structurally, the design of the outlet 13 and the guide trough 14 allows the degassing agent to be output from the lower middle part of the rod 1a, working in conjunction with the rising bubbles at the bottom to ensure the degassing agent's full effectiveness. The agent gradually rises with the bubbles and is finally collected by the degassing mechanism.

[0036] Example 2

[0037] refer to Figure 4 Compared to Embodiment 1, the fan blade 31 is spiral-shaped, and a housing 32 is fitted over the fan blade 31. A material collection tank 33 is provided on the housing 32 at the output end of the fan blade 31. This spiral-shaped fan blade 31 structure can collect the rolled-up impurities into the housing 32 during the impurity removal process, and then feed them into the material trough as the blade rotates, thus extending the impurity removal time.

[0038] The fan blades 31, horizontal shaft 3, and shell 32 used in this technical solution are all designed and manufactured using high-temperature resistant materials, such as ceramic fiber and zirconium alloy. Depending on the actual position of action, they can be flexibly selected and are not limited here. The hollow rotating rod 1 still uses traditional graphite material.

[0039] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A deep-bed filtration and purification process for molten aluminum alloy, characterized in that, Includes the following steps: a. The aluminum alloy raw material is put into the furnace and heated to melt it into aluminum liquid. An alkali removal agent is added and the liquid is filtered through the permeable bricks at the bottom of the furnace. After that, it is filtered to remove slag, thus achieving a purification process. b. Transfer the aluminum liquid obtained in step a into a holding furnace and degas and refine it through a purification device to form a secondary purification process. c. Perform secondary filtration to remove slag from the aluminum liquid obtained in step b; The purification device is located above the heat preservation furnace and includes a frame (100), a hollow rotating rod (1) that can be lifted and lowered on the frame (100) for rotary blowing and degassing, and a cleaning mechanism for removing impurities. The hollow rotating rod (1) is connected to a rotating motor (101) that drives it to rotate, and the hollow rotating rod (1) is connected to a gas delivery pipe (102) for inert gas delivery. The impurity removal mechanism includes a support (2) that can move up and down with the hollow rotating bar (1), a horizontal shaft (3) located at the lower end of the support (2) and arranged radially along the hollow rotating bar (1), and a number of fan blades (31) arranged on the horizontal shaft (3) for picking up impurities. The horizontal shaft (3) is connected to a motor that drives it to rotate so as to drive each fan blade (31) to move. The support (2) is connected to a support motor (21) and its transmission assembly (22) that drives it to rotate around the hollow rotating bar (1). The air supply pipe (102) is connected to a feeder (4) for adding impurity removal agent; The hollow rotating rod (1) includes a rod body (1a) and a disc body (1b) located at the bottom end of the rod body (1a). Air passages (11) are opened in the rod body (1a) and the disc body (1b). The bottom of the disc body (1b) is a frustum structure, and air holes (12) are evenly distributed on the conical surface of the frustum structure. The rod (1a) has a discharge port (13) extending radially for discharging the impurity remover, and the air passage (11) has a guide groove (14) for guiding the impurity remover to the discharge port (13).

2. The deep-bed filtration and purification process for molten aluminum alloy as described in claim 1, characterized in that: The fan blade (31) is spiral-shaped, and a housing (32) is attached to the fan blade (31). A material tank (33) for collecting materials is provided on the housing (32) at the output end of the fan blade (31).

3. A deep-bed filtration and purification process for molten aluminum alloy according to claim 1 or 2, characterized in that: The primary filtration and secondary filtration for slag removal employ 30-mesh and 50-mesh foam ceramic filter plates, respectively.

Images