Method for purifying titanium and titanium alloy return chips

Abstract

The application discloses a titanium and titanium alloy return scrap pure treatment method, integrates multiple pure treatment points, establishes a full-automatic titanium and titanium alloy return scrap treatment production line, and specifically includes the following pure treatment procedures: crushing and screening, cleaning and rinsing, dehydration and drying, high specific gravity separation, oxide separation, high-density separation, manual selection, multi-stage magnetic separation, and cloth feeding and barrel loading. After treatment, qualified titanium and titanium alloy return scrap meeting the recycling and smelting requirements can be obtained. The titanium and titanium alloy return scrap produced by the method can be used as raw material for smelting, which can greatly reduce the production cost and energy consumption of titanium and titanium alloy materials, can recycle national strategic rare metal resources, reduces the consumption of rare mineral resources and carbon emission, and has important strategic significance.

Description

Technical Field

[0001] This invention belongs to the field of titanium and titanium alloy material processing technology, and relates to a method for purifying titanium and titanium alloy scrap. Background Technology

[0002] Titanium and titanium alloy processed materials are characterized by long processing steps and low yield. From sponge titanium to processed materials, only 0.4 to 0.6 kg of sponge titanium per kilogram enters the finished product on average. Therefore, the entire processing process generates a large amount of residue and waste. In addition, the preparation of sponge titanium consumes a lot of energy. If the titanium residue can be recycled and remelted into ingots, the energy and resource consumption will be significantly reduced. However, in the process of using titanium residue to produce ingots, various impurities are easily introduced, including oil, oxides, TiN, and chipping of cemented carbide cutting tools.

[0003] European and American countries have been using the technology of adding recycled materials to smelt titanium and titanium alloys for over 30 years. The technology is relatively mature, and relevant standards and industry specifications have been established, such as AMS 2380 in the United States and EN 2955 in Europe. In the production of aerospace-grade titanium and titanium alloys, European and American countries can add approximately 30% to 50% recycled materials, while in civilian-grade titanium and titanium alloys, the proportion can be close to 100%. For example, Perryman Company in the United States can produce 12,500 pounds (approximately 6 tons) of titanium and titanium alloy ingots using nearly 100% recycled materials, while VDM in Germany uses titanium scrap mixed with sponge titanium to produce 13.2-ton Ti-6Al-4V titanium and titanium alloy round ingots.

[0004] However, China currently lags significantly behind foreign countries in the technology for processing recycled titanium and titanium alloy materials. The management of recycled materials lacks rational methods, and the lack of scientific management during the generation of residual titanium leads to contamination and chaotic storage and transportation, making it difficult to use in high-end titanium products or reintegrate into the titanium production chain. Therefore, the purification treatment of recycled titanium and titanium alloy materials is a crucial prerequisite for utilizing them in the smelting of titanium and titanium alloy ingots. Summary of the Invention

[0005] The purpose of this invention is to provide a method for purifying titanium and titanium alloy scrap, which solves the problem of difficult titanium scrap recycling in the prior art.

[0006] The technical solution adopted in this invention is a purification treatment method for titanium and titanium alloy scrap. The specific operation process is as follows: after recovering titanium and titanium alloy scrap, it undergoes purification treatment processes such as crushing and screening, washing and rinsing, dehydration and drying, high specific gravity separation, three-stage magnetic separation, oxide separation, removal of high-density inclusions, and manual material picking to prepare high-purity titanium and titanium alloy ingot scrap.

[0007] The invention is further characterized by:

[0008] The purification treatment method for titanium and titanium alloy scrap is implemented according to the following steps:

[0009] Step 1: Collect the scrap generated during the machining process of titanium and titanium alloys;

[0010] Step 2: After crushing and screening, a magnetic separation point is set up every 1 to 2 processes. A total of five magnetic separation points are set up in the purification treatment line.

[0011] Step 3: The collected returned scrap is crushed by a crusher and then screened by a screening machine. After that, it undergoes primary magnetic separation to initially remove magnetic inclusions.

[0012] Step 4: The crushed and screened material is washed and rinsed, then dehydrated and dried, and then subjected to a second magnetic separation.

[0013] Step 5: Use a gravity separator to remove high-density particles and perform a third-stage magnetic separation.

[0014] Step 6: Separate oxides using a color sorter;

[0015] Step 7: Remove high-density inclusions using an X-ray sorting machine;

[0016] Step 8: The purification line has 2 to 4 stations for manual material handling, and the material can only be placed into barrels after passing through the fourth and fifth stages of magnetic separation.

[0017] In step 2, the height of each stage of the multi-stage magnetic separation is ≤100mm;

[0018] In step 3, the length range of the screened chip size is 2 to 50 mm.

[0019] The specific process parameters for cleaning and rinsing in step 4 are: three cleaning and three rinsing, cleaning and rinsing temperature 50℃~100℃, and drum speed 1-10rpm.

[0020] The specific process parameters for dehydration and drying in step 4 are: drying temperature 250℃~350℃, and the moisture content of the scrap material within 300ppm.

[0021] In step 5, the high-specific-gravity sorting vibration frequency of the gravity separator is 10-50Hz.

[0022] In step 6, the frequency of the feed motor of the color sorter is 250-350Hz;

[0023] In step 7, the foreign matter / background sensitivity of the X-ray sorting machine is 10–150 lux.

[0024] The beneficial effects of this invention are

[0025] The present invention discloses a method for purifying titanium and titanium alloy scrap generated from the processing of titanium and titanium alloy ingots using a peeling machine. This method recycles and purifies the scrap to obtain titanium and titanium alloy scrap that meets smelting requirements. The purification process of the fully automated titanium and titanium alloy scrap processing production line specifically includes the following steps: crushing and screening, washing and rinsing, dehydration and drying, high-density separation, oxide separation, high-density separation, manual sorting, multi-stage magnetic separation, and packing into drums. Using the titanium and titanium alloy scrap produced by this method as raw material for smelting can significantly reduce the cost of titanium and titanium alloy materials while ensuring metallurgical quality. It also allows for the recycling of national strategic rare and precious metal resources, reducing the consumption of rare mineral resources and carbon emissions, which is of significant strategic importance. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the purification process of titanium and titanium alloy scrap in an embodiment of the present invention.

[0027] Figure 2 This is a physical image of a fully automated titanium and titanium alloy scrap processing production line according to an embodiment of the present invention;

[0028] Figure 3 These are comparative images of the morphology of titanium and titanium alloy scrap before and after the scrap recovery process according to an embodiment of the present invention.

[0029] Figure 4 This is a comparison of the moisture content test results of titanium and titanium alloy scrap before and after the processing in an embodiment of the present invention;

[0030] Figure 5 The image shows the results of a high-density separation test using an X-ray machine for artificially adding high-density inclusions to titanium and titanium alloy scrap materials according to an embodiment of the present invention.

[0031] Figure 6 The graph shows the test results of the magnetic separation netting rate of titanium and titanium alloy scrap in an embodiment of the present invention. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] This invention provides a method for purifying recycled titanium and titanium alloy scrap. After purifying the recycled ingot scrap, qualified recycled titanium and titanium alloy scrap suitable for smelting is obtained. The scrap size is controlled within the range of 2–50 mm, and the moisture content is controlled within the range of 300 ppm. After multi-stage magnetic separation, the removal rate of magnetic inclusions is nearly 100%, after high-density separation, the removal rate of high-density inclusions is nearly 100%, and after oxide separation, the oxide removal rate is greater than 80%. This method for purifying recycled titanium and titanium alloy scrap has a high and very stable yield, making it suitable for industrial production.

[0034] like Figure 1 and Figure 2 As shown, please follow these steps:

[0035] Step 1: Collect the recycled scrap generated from the peeling of titanium and titanium alloy ingots and transport it to the established fully automated titanium and titanium alloy recycled scrap processing line for purification treatment. The purification treatment points of the production line are in the following order: crushing and screening, washing and rinsing, dehydration and drying, high specific gravity separation, three-stage magnetic separation, oxide separation, high density inclusion removal, and manual material handling. The grades of recyclable titanium and titanium alloy scrap include, but are not limited to, CpTi, TC4, TC4-DT, TC4 ELI, TA15, TC11, etc.

[0036] Step 2: After crushing and screening, a magnetic separation point is set up every 1 to 2 processes. A total of five magnetic separation points are set up in the purification treatment line. The magnetic separation height of each stage of multi-stage magnetic separation is ≤100mm.

[0037] Step 3: The collected returned scrap is crushed by a crusher and then screened by a screening machine. The length of the screened scrap ranges from 2 to 50 mm. Then, a primary magnetic separation is performed to initially remove magnetic inclusions.

[0038] Step 4: After the crushed and screened scrap is washed and rinsed three times, it is dehydrated and dried. The washing and rinsing temperature is 50℃~100℃, the drum speed is 1-10rpm, the drying temperature is 250℃~350℃, the moisture content of the scrap is controlled within 300ppm, and a second magnetic separation is performed.

[0039] Step 5: Use a gravity separator to screen for high specific gravity particles. The vibration frequency for high specific gravity separation is 10-50Hz, followed by a third-stage magnetic separation.

[0040] Step 6: Oxides are separated by a color sorter. The feed motor of the color sorter has a frequency of 250-350Hz, and the oxide removal rate is greater than 80%.

[0041] Step 7: Remove high-density inclusions using an X-ray separator. The X-ray separator has a foreign matter / background sensitivity of 10-150 lux and a removal rate of nearly 100%.

[0042] Step 8: The purification process line has 2 to 4 stations for manual material sorting to remove visible debris that is bulky or has an abnormal color. The material can only be packed into barrels after passing through the fourth and fifth stages of magnetic separation.

[0043] Figure 3 The images show a comparison of the morphology of titanium and titanium alloy scrap before and after processing in an embodiment of the present invention. The length of the processed TC4-DT titanium and titanium alloy scrap ranges from 2 to 50 mm.

[0044] Figure 4 This figure shows a comparison of the moisture content of titanium and titanium alloy scrap before and after treatment, according to an embodiment of the present invention. The change in moisture content of the scrap before and after treatment was detected using the oven drying weight loss method. Figure 4 It can be seen from the data that after treatment, the average moisture content of the returned scrap is ≤0.02%;

[0045] Figure 5 This image shows the results of a high-density separation test using an X-ray machine on titanium and titanium alloy scrap with artificially added high-density inclusions, as described in this invention. The detection accuracy and sorting efficiency of the X-ray machine's high-density separation were verified by preparing a tungsten carbide standard sample. Figure 5 It can be seen that all the artificially added high-density inclusions marked with red tape can be effectively screened out by the X-screen machine through density difference screening, with a screening rate of 100%.

[0046] Figure 6 This is a graph showing the test results of the magnetic separation cleanliness of titanium and titanium alloy recycled scrap in an embodiment of the present invention. The automated recycled scrap processing line has a total of 5 magnetic separation points. Small iron pieces marked with brightly colored paint pens were placed at the magnetic separation points. All the manually added iron pieces were selected at the accepted magnetic separation points, achieving a cleanliness rate of 100%.

[0047] The titanium and titanium alloy scrap produced by the purification treatment method of the present invention can be used as raw material for smelting, which will greatly reduce the production cost and energy consumption of titanium and titanium alloy materials. It can recycle the country's strategic rare and precious metal resources, reduce the consumption of rare mineral resources and carbon emissions, and has important strategic significance.

Claims

1. A method for purifying titanium and titanium alloy scrap, characterized in that, The specific operation process is as follows: After recovering titanium and titanium alloy scrap, it undergoes a purification process of crushing and screening, washing and rinsing, dehydration and drying, high specific gravity separation, three-stage magnetic separation, oxide separation, high density inclusion removal, and manual material picking to prepare high-purity titanium and titanium alloy ingot return scrap. The specific steps are as follows: Step 1: Collect the scrap generated during the machining process of titanium and titanium alloys; Step 2: After crushing and screening, a magnetic separation point is set up every 1 to 2 processes. A total of five magnetic separation points are set up in the purification treatment line; the height of each stage of multi-stage magnetic separation is ≤100mm. Step 3: The collected returned scrap is crushed by a crusher and then screened by a screening machine. After that, a primary magnetic separation is performed to initially remove magnetic inclusions. The length range of the screened scrap is 2~50mm. Step 4: The crushed and screened material is washed and rinsed, then dehydrated and dried, and then subjected to a second magnetic separation. The specific process parameters for cleaning and rinsing are: three cleaning and three rinsing, cleaning and rinsing temperature 50℃~100℃, drum speed 1-10rpm; the specific process parameters for dehydration and drying are: drying temperature 250℃~350℃, and the moisture content of the scrap material within 300ppm. Step 5: Use a gravity separator to screen for high specific gravity and perform a third-stage magnetic separation; the vibration frequency of the gravity separator for high specific gravity separation is 10~50Hz. Step 6: Oxides are separated using a color sorter; the feed motor frequency of the color sorter is 250~350Hz. Step 7: Remove high-density inclusions using an X-ray sorting machine; the foreign matter / background sensitivity of the X-ray sorting machine is 10~150 lux. Step 8: The purification line has 2-4 stations for manual material handling, and the material can only be placed into barrels after passing through the fourth and fifth stages of magnetic separation.

Images