CN-122010173-A - Production method of high-purity hafnium compound

CN122010173ACN 122010173 ACN122010173 ACN 122010173ACN-122010173-A

Abstract

The invention relates to high-purity preparation of key metals, and discloses a production method of a high-purity hafnium compound, which comprises the following steps of S1, carrying out a melting reaction on a hafnium-containing material, flux metal, zirconium salt and a salt-containing material together to obtain a hafnium-containing molten salt, wherein the melting temperature in the melting reaction is 700-1250 ℃, the mass ratio of hafnium in the hafnium-containing material to zirconium in the zirconium salt is more than or equal to 2.0, the zirconium content in the hafnium-containing molten salt is less than or equal to 0.5 wt%, and the hafnium content is more than or equal to 1 wt%, and S2, further separating the hafnium-containing molten salt obtained in the step S1 to obtain the high-purity hafnium compound. The method can realize the preparation of the high-purity hafnium product without multiple high-temperature fractionation or multistage extraction treatment, has the advantages of short flow, simple operation and the like, and effectively solves the problem of separating zirconium from hafnium in the crude zirconium salt while removing zirconium in the molten salt, thereby realizing the maximum utilization of the value of the raw materials, and therefore, the process has better economic benefit.

Inventors

REN GUOXING
LIU DONGFU
ZHAO ZHONGWEI
CHEN WEIDONG
WANG LIJUN
Guo Xuzhao
LI YONGLI
GAO BIAOFENG
YOU XIAOGANG
XU WENHUA

Assignees

郑州大学

Dates

Publication Date: 20260512
Application Date: 20260312

Claims (9)

1. A method for producing a high purity hafnium compound, comprising the steps of: S1, carrying out a melting reaction on a hafnium-containing material, flux metal, zirconium salt and a salt-containing material together to obtain a hafnium-containing molten salt, wherein the melting temperature in the melting reaction is 700-1250 ℃, the mass ratio of hafnium in the hafnium-containing material to zirconium in the zirconium salt is more than or equal to 2.0, the zirconium content in the hafnium-containing molten salt is less than or equal to 0.5 wt%, and the hafnium content is more than or equal to 1 wt%; S2, further separating the hafnium-containing molten salt obtained in the step S1 to obtain the high-purity hafnium compound.
2. The method for producing a high purity hafnium compound according to claim 1, wherein in step S1, the zirconium content in the molten salt containing hafnium in step S1 is not more than 0.2 wt% and the hafnium content is not less than 5: 5 wt%.
3. The method according to claim 1, wherein in the step S1, the hafnium-containing material is at least one of zirconium metal containing hafnium, zirconium sponge containing hafnium, zirconium-based alloy containing hafnium, zirconium metal containing hafnium, zirconium-based alloy containing hafnium, hafnium metal, hafnium sponge, and hafnium-based alloy.
4. The method of producing a high purity hafnium compound according to claim 1, wherein in step S1, the zirconium salt is at least one of zirconium tetrachloride, zirconium tetrafluoride, sodium fluorozirconate, potassium fluorozirconate, and ammonium fluorozirconate.
5. The method for producing a high purity hafnium compound according to claim 1, wherein in step S1, the flux metal is Zn, sn, cu, fe, ni, ag or at least one of their alloys, and the mass of the flux metal is 0.3 to 40 times the mass of the hafnium-containing material.
6. The method for producing a high purity hafnium compound according to claim 1, wherein in the step S1, the salt-containing material is at least one of sodium chloride, potassium chloride, sodium fluoride, potassium fluoride, calcium chloride, calcium fluoride, lithium chloride, lithium fluoride, magnesium chloride, magnesium fluoride, aluminum chloride, aluminum fluoride, and double salts thereof, and the mass of the salt-containing material is 0.5 to 25 times that of the hafnium-containing material.
7. The method for producing a high purity hafnium compound according to claim 1, wherein said melting reaction in step S1 is performed under vacuum or in a protective atmosphere of at least one of hydrogen, nitrogen, argon, helium, and neon.
8. The method for producing a high purity hafnium compound according to claim 1, wherein in step S2, the further separation process of the molten salt containing hafnium is as follows: Leaching the hafnium-containing molten salt to obtain a leaching solution, and adjusting the pH value of the leaching solution to be more than 2.0 to obtain high-purity Hf (OH) 4 and high-purity HfO 2 NH 2 O, high purity HfOCl 2 At least one of 8H 2 O, and leaching temperature is more than or equal to 20 ℃.
9. The method for producing a high purity hafnium compound according to claim 1, wherein in step S2, the further separation process of the molten salt containing hafnium is as follows: introducing chlorine gas and hydrogen chloride or adding one of ammonium chloride into the fused salt containing hafnium, controlling the reaction temperature to be more than or equal to 400 ℃, volatilizing hafnium in the fused salt in a hafnium tetrachloride form, and condensing and collecting to obtain a high-purity hafnium tetrachloride product.

Description

Production method of high-purity hafnium compound Technical Field The invention relates to the technical field of high-purity preparation of key metals, in particular to a production method of a high-purity hafnium compound. Background In the field of semiconductor fabrication, the introduction of high dielectric constant (high K) materials is a key to continuing moore's law. HfO 2, by virtue of its high dielectric constant of 20-25, excellent thermal stability, and good compatibility with silicon processes, becomes a core high K dielectric to replace conventional silicon dioxide. After the chip manufacturing process enters the nanometer scale, a thicker physical gate insulating layer can be effectively constructed, so that leakage current caused by quantum tunneling is greatly inhibited, and key power consumption and reliability bottlenecks in the chip miniaturization process are overcome. Therefore, hfO 2 has been the necessary choice for manufacturing advanced logic and memory chip gate dielectrics of 5 nm and below. Hafnium and zirconium are closely symbiotic in nature, and the production of hafnium depends on the smelting process of zirconium. Zirconium/hafnium separation is very difficult because zirconium and hafnium belong to the same family, and the ion radii are nearly identical, resulting in very close physical and chemical properties, and particularly, deep separation of zirconium is important in the process of producing high-purity HfO 2. Because of the extremely stringent requirements of nuclear grade zirconium on hafnium, the hafnium content needs to be less than 100ppm, while the requirements of nuclear grade hafnium on zirconium need only be less than 2%, resulting in the prior zirconium/hafnium separation processes being primarily for purifying zirconium. Currently, three industrially applied zirconium/hafnium separation technologies mainly include MIBK-HSCN extraction, TBP-HNO 3 extraction and fractional crystallization processes, but none of these technologies can obtain high purity HfO 2 or other high purity hafnium products. In order to prepare high-purity hafnium and compounds thereof, chinese patent publication No. CN120136161A discloses a method for preparing high-purity hafnium oxide by synergistic extraction, P204 and TBP are used as extracting agents to prepare high-purity hafnium oxide by synergistic extraction, and the process can deeply separate zirconium/hafnium, but the process needs to consume a large amount of acid, and a large amount of waste water is generated to affect the environment. The Chinese patent of invention with publication number CN120841568A discloses a method for preparing high-purity hafnium tetrachloride by wet extraction and separation, which utilizes tributyl phosphate, trioctylphosphine oxide and sulfonated kerosene to compound to obtain a compound extractant for extraction, but the method has the problems of high reagent cost, complex process flow, possibility of serious pollution, safety accidents and the like. The Chinese patent publication No. CN119706928A discloses a preparation method of high-purity hafnium oxide, which adopts the technological processes of alkali fusion, water immersion, dissolution, sodium sulfate impurity removal, evaporation of a finished product, oxalic acid precipitation, washing and calcination, but the technological process is very complex, the loss of hafnium is high, and the economic benefit is poor. The Chinese patent with the authorization number of CN111994951B discloses a method for recovering hafnium tetrachloride in the process of purifying crude zirconium tetrachloride, which utilizes the difference of saturated vapor pressures of HfCl 4 and ZrCl 4 in molten salt-potassium aluminum chlorate to realize the separation of zirconium and hafnium. However, the collection of hafnium tetrachloride is very complicated, the recovery time is long, and the production efficiency of the process is low. The Chinese patent No. CN119287185B discloses a preparation method of low-oxygen high-purity metal hafnium, which adopts deoxidizer and fluxing agent to make thermal reduction to prepare high-purity hafnium, but the process has high cost and can produce a large amount of acid wastewater. The Chinese patent No. CN103862059B discloses a method for preparing high-purity hafnium by using potassium hafnium fluoride as raw material, which uses reducing agent to make potassium hafnium fluoride undergo the processes of reduction, washing and drying so as to obtain hafnium powder, but the method has high requirements for raw material purity, and the purity of the obtained hafnium powder is up to above 98%, and the purity of the obtained hafnium powder is unstable (only 84% in example 2). The Chinese patent of invention No. CN112624194B discloses a method for preparing high-purity hafnium tetrachloride by a one-step method, which comprises the steps of mixing hafnium oxide and carbon powder, introducing chlorine for reaction, sequentially