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CN-121976062-A - Niobium ingot preparation method capable of synchronously improving refining effect and production efficiency

CN121976062ACN 121976062 ACN121976062 ACN 121976062ACN-121976062-A

Abstract

The invention belongs to the technical field of smelting and purifying rare refractory metals, and discloses a preparation method of a niobium ingot for synchronously improving refining effect and production efficiency. The method comprises the steps of taking a specific component smelting niobium plate prepared by combining a vacuum aluminothermic method with horizontal electron beam smelting as a raw material, shearing the specific component smelting niobium plate into long and short niobium strips with specific dimensions, layering and stacking, precisely lapping and fixed-point binding to prepare a 1 st-N unit raw material, optimizing an electron beam smelting furnace, arranging an annular cooling die wall outside an ingot casting die, smelting the unit raw material sequentially by using horizontal feeding and vertical feeding electron beams, and strictly controlling two-stage smelting parameters to prepare a high-purity niobium ingot. The invention realizes the optimal matching with the energy distribution of the electron beam through the structural design of the unit raw materials, improves the purification effect, avoids the phenomenon of smelting and chipping, ensures the utilization rate of the raw materials and the process stability, and simultaneously cooperates with the annular cooling die wall for enhanced cooling to further improve the quality and the production efficiency of the cast ingot.

Inventors

  • ZHANG DENGKUI
  • WANG WEI
  • ZHU JIAQI
  • Jie Yongshuai
  • YANG WENBIN
  • YAN WEI
  • WANG YUHAN
  • GUAN YUANHONG

Assignees

  • 承德天大钒业股份有限公司

Dates

Publication Date
20260505
Application Date
20260211

Claims (8)

  1. 1. The preparation method of the niobium ingot capable of synchronously improving the refining effect and the production efficiency is characterized by comprising the following steps of: (1) Preparing raw materials, namely taking a smelting niobium plate prepared by combining a vacuum aluminothermic process and a horizontal electron beam smelting process as raw materials; (2) Preparing unit raw materials: The 1 st unit raw material preparation comprises the steps of shearing a smelting niobium plate into rectangular long niobium strips with the size of (70-80) × (16-20) × (2-3) cm by using a plate shearing machine, cutting off 1/3 of the total length of the long niobium strips to obtain short niobium strips, stacking 3-5 short niobium strips as a lower layer, stacking 3-5 long niobium strips above the lower layer as an upper layer, and longitudinally aligning one sides of the lower layer and the upper layer of the niobium strips, binding all the niobium strips for 2 times by adopting niobium wires, wherein binding positions are respectively 1-2cm and 4-6cm away from the longitudinal line of the boundary of the long and short niobium strips, so as to obtain the 1 st unit raw material; The preparation of the 2 nd-N unit raw material comprises the steps of stacking 3-5 long niobium strips as a lower layer, stacking 3-5 long niobium strips as an upper layer, stacking the upper layer and the lower layer in a lap joint mode, wherein the dislocation amount is 1/4-1/3 of the total length of the long niobium strips, binding all the niobium strips for 2 times by adopting niobium wires, and respectively obtaining the 2 nd unit raw material at positions which are 1-2cm and 4-6cm away from a lap joint longitudinal line of the upper layer and the lower layer, wherein the preparation mode of the 3 rd-N unit raw material is consistent with that of the 2 nd unit; (3) Smelting by horizontal feeding, namely tightly discharging all unit raw materials and placing the unit raw materials in a horizontal feeding bin of a double-gun electron beam smelting furnace, and smelting in a horizontal feeding mode to obtain a primary niobium ingot; (4) And (3) smelting the primary niobium ingot in a vertical feeding mode to obtain the high-purity niobium ingot.
  2. 2. The method for preparing the niobium ingot capable of synchronously improving the refining effect and the production efficiency according to claim 1, wherein the chemical components of the smelting niobium plate are ：Ta≤0.01%、O≤0.005%、N≤0.004%、C≤0.002%、Si≤0.005%、Mo≤0.001%、Ti≤0.002%、Al≤0.005%、Cu≤0.002%、Cr≤0.003%、Fe≤0.005%、W≤0.001%、Ni≤0.002%、Zr≤0.002%, weight percent, and the balance is Nb.
  3. 3. The method for producing niobium ingots capable of synchronously improving refining effect and production efficiency according to claim 1, wherein the length of the lower layer exceeding the upper layer in the direction parallel to the horizontal plane is the dislocation amount in the preparation of the 2 nd-N unit raw materials in the step (2).
  4. 4. The method for preparing the niobium ingot capable of synchronously improving the refining effect and the production efficiency according to claim 1, wherein smelting parameters in the step (3) are controlled to be 0.01-0.05Pa in smelting vacuum degree, 530-630kW in smelting power, 90-110kg/h in smelting speed, 3-5r/min in ingot pulling speed and 35-41 kW.h/kg in specific electric energy.
  5. 5. The method for preparing the niobium ingot capable of synchronously improving the refining effect and the production efficiency according to claim 1, wherein smelting parameters are controlled in the step (4) to be that the smelting vacuum degree is 0.001-0.003Pa, the smelting power is 610-670kW, the smelting speed is 60-80kg/h, the ingot pulling speed is 1-2r/min and the specific electric energy is 46-50 kW.h/kg.
  6. 6. The method for preparing the niobium ingot capable of synchronously improving the refining effect and the production efficiency according to claim 1, wherein the chemical composition of Gao Chunni ingot is ：Ta≤0.006%、O≤0.0016%、N≤0.001%、C≤0.0005%、Si≤0.001%、Mo≤0.0005%、Ti≤0.0001%、Al≤0.0004%、Cu≤0.0001%、Cr≤0.0001%、Fe≤0.0004%、W≤0.0008%、Ni≤0.0001%、Zr≤0.0001%, percent by weight and the balance is Nb.
  7. 7. The preparation method of the niobium ingot capable of synchronously improving the refining effect and the production efficiency according to claim 1 is characterized by further comprising the steps of detecting chemical components of the high-purity niobium ingot in a mode of taking 3 sample points at the head, middle and tail of the niobium ingot respectively, analyzing and averaging the chemical components of the 9 sample points, and simultaneously carrying out peeling treatment and ultrasonic detection on the niobium ingot to ensure that cracks and hole defects are not visible to naked eyes.
  8. 8. The method for preparing the niobium ingot capable of synchronously improving refining effect and production efficiency according to any one of claims 1 to 7, wherein an annular cooling mold wall is sleeved around an ingot mold in the double-gun electron beam melting furnace, the length of the annular cooling mold wall exceeds the length of the ingot mold by 300 to 500mm, and the diameter of a pipeline of the annular cooling mold wall is transited from 1/8 of the diameter of the ingot mold to 1/3 of the diameter of the ingot mold.

Description

Niobium ingot preparation method capable of synchronously improving refining effect and production efficiency Technical Field The invention relates to the technical field of rare refractory metal smelting and purifying, in particular to a niobium ingot preparation method capable of synchronously improving refining effect and production efficiency. Background Niobium is a key strategic material with excellent superconducting performance, high strength, corrosion resistance and good processing performance, and is increasingly widely and irreplaceable in the high-end fields of superconducting technology, industrial electronics, aerospace, atomic energy and the like. Along with the technical upgrade of equipment such as human body nuclear Magnetic Resonance Imaging (MRI), nuclear magnetic resonance spectrometer (NMR), magnetic control Czochralski silicon, radio frequency superconducting cavity and the like to high power, high precision and long service life, the requirements on the physicochemical indexes such as purity, hardness and the like of niobium materials for core components are more severe, meanwhile, the market scale expansion of the fields directly drives the continuous discharge of the requirements of niobium ingots, and the double challenges are provided for the high quality and the large scale preparation of the niobium ingots. At present, a technology for preparing niobium ingots by combining an aluminothermic method with electron beam furnace smelting is a mainstream in the field of high-end application. According to the technology, a crude niobium raw material is obtained through aluminothermic reduction, and impurities are removed through high-temperature refining of an electron beam furnace, so that the requirement of a high-end scene on the quality of niobium ingots is met. The complex application scenes of the radio frequency superconducting cavity, the high-field magnet and the like put forward very strict standards on the quality of niobium ingots, and specifically comprise uniform chemical components, uniform and consistent tissue structure, no allowance of specific and individual coarse grains, no allowance of metallurgical defects such as inclusions, cracks, shrinkage cavities and the like, and the content is within a specified range. Aiming at the severe requirements, the related technical fields are continuously upgraded, but the bottleneck to be broken through still exists. Patent CN104480319a discloses a method for preparing a high-purity niobium ingot for a radio frequency superconducting cavity, which takes an industrial pure niobium lath as a raw material, and finally obtains the high-purity niobium ingot by carrying out vacuum electron beam melting on the niobium lath for 3-7 times. However, the method has obvious defects that firstly, the production period is longer than 72 hours due to repeated smelting, the production efficiency is lower, meanwhile, the energy consumption is greatly increased in the repeated smelting process, the production cost is obviously increased, and secondly, only two parameters of specific electric energy and vacuum degree are concerned in the electron beam furnace smelting process, but the quantitative evaluation and targeted optimization of refining effects such as impurity removal efficiency, component uniformity and the like in the refining process are not carried out, and the stability of the product quality is difficult to ensure. Patent CN117684024a discloses a method for producing high-purity niobium ingot by physical purification, which uses niobium produced by an aluminothermic reduction method as a raw material, sequentially carries out acid washing, water washing and drying, then welds into an electrode, carries out vacuum electron beam smelting to obtain niobium ingot, and finally carries out mechanical processing and high-temperature degassing treatment to obtain the high-purity niobium ingot. However, the method has obvious defects that firstly, the process flow is complex, the method comprises a plurality of operation steps of acid washing, water washing, degassing and the like, the parameter control difficulty of each step is high, the operation is tedious, new impurity elements are easy to introduce in the acid washing process, the energy saving consumption of the water washing and drying rings is high, the comprehensive production efficiency is low, secondly, only the parameters such as vacuum degree, smelting specific electric energy, electron gun circulating current, smelting speed and the like are focused in the smelting process of the electron beam furnace, the specific description of the refining effect is not involved, and in addition, the whole process efficiency is low, the single production period exceeds 48 hours, and the method is difficult to adapt to the requirement of large-batch responsive production although the final product meets the component index requirement. At present, the technical proposal of integration fo