阅读说明：本技术 一种从废钽/铌酸锂中制备高纯五氯化钽/铌和氯化锂的方法 (Method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate ) 是由 李焌源 田吉英 王一舟 向小绢 任改梅 黎静 于 2021-01-04 设计创作，主要内容包括：本发明公开了一种从废钽/铌酸锂中制备高纯五氯化钽/铌和氯化锂的方法,以酸碱清洗前处理的废钽/铌酸锂为钽/铌锂金属来源,石油焦、活性炭、炭黑为碳源,破碎后按一定比例混匀,经等离子体活化后,装入氯化炉中升温通入高纯氯气进行反应,产生的混合气控制温度280-400℃,通过高温除尘和过滤段除铁后,进入温度控制150-220℃的收料段冷却回收高纯五氯化钽/铌,氯化炉的残料通过水浸回收高纯氯化锂。本发明实现了高纯五氯化钽/铌和氯化锂的制备,解决了传统废钽/铌酸锂回收工艺普遍存在产品纯度不高、回收率低、工艺繁琐等问题,本发明具有工艺设备简单、原料完全利用、成本低廉、清洁环保的突出优点。(The invention discloses a method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate, which comprises the steps of taking waste tantalum/lithium niobate pretreated by acid-base cleaning as a tantalum/niobium lithium metal source, taking petroleum coke, activated carbon and carbon black as carbon sources, crushing, uniformly mixing according to a certain proportion, activating by plasma, putting into a chlorination furnace, heating, introducing high-purity chlorine gas for reaction, controlling the temperature of generated mixed gas to be 280 plus materials and 400 ℃, removing iron by a high-temperature dust removal and filtration section, entering a material receiving section with the temperature controlled to be 150 plus materials and 220 ℃, cooling and recovering the high-purity tantalum/niobium pentachloride, and recovering the high-purity lithium chloride from residual materials of the chlorination furnace by water leaching. The method realizes the preparation of high-purity tantalum/niobium pentachloride and lithium chloride, solves the problems of low product purity, low recovery rate, complex process and the like of the traditional waste tantalum/lithium niobate recovery process, and has the outstanding advantages of simple process equipment, complete utilization of raw materials, low cost, cleanness and environmental protection.)

1. A method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate is characterized by comprising the following steps:

1) pretreatment of waste tantalum/lithium niobate

Washing the waste tantalum/lithium niobate particles by pure water and hydrochloric acid to remove surface impurity ash;

2) pretreatment of carbon source

Crushing the carbon source to more than 100 meshes;

3) material mixing and activation

Mixing the waste tantalum/lithium niobate obtained in the step 1) and the carbon source obtained in the step 2), and then carrying out plasma activation to break the crystal structure of the tantalum/lithium niobate and realize grain refinement and carburization;

4) chlorination reaction

Putting the waste tantalum/lithium niobate and carbon mixed material prepared in the step 3) into a chlorination furnace, vacuumizing the chlorination furnace and replacing with argon, finally introducing high-purity chlorine when the temperature of the chlorination furnace is raised to above 700 ℃, allowing the mixed material to perform chlorination reaction, allowing the generated tantalum/niobium pentachloride and carbon oxide to enter a high-temperature dust removal section with the temperature of above 400 ℃ in the form of steam, removing carried tantalum/lithium niobate, carbon and lithium chloride-free dust, cooling the gas to 255-;

5) lithium chloride separation

Washing the residual residue in the step 4) and the dust in the high-temperature dust removal section by pure water, dissolving the generated lithium chloride in an aqueous solution, and concentrating and crystallizing to obtain the lithium chloride powder with the purity of not less than 99.8%.

2. The method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate according to claim 1, wherein the carbon source in the step 2) is activated carbon, petroleum coke, carbon black or acetylene black.

3. The method for preparing high purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate as claimed in claim 1, wherein the pretreatment temperature of the carbon source in the step 2) is 800-1200 ℃.

4. The method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste lithium tantalate according to claim 1, wherein the molar ratio of the waste tantalum/lithium niobate and the carbon source in the step 3) is 1: 1.5-5.

5. The method of claim 1, wherein the carburization in step 3) produces LiTaO_3-XC_X(X ═ 0-3) in a complex crystalline form.

6. The method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate according to claim 1, wherein the molar ratio of the chlorination reaction waste tantalum/lithium niobate and chlorine gas in the step 4) is 1: 3-5.

7. The method for preparing high purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate as claimed in claim 1, wherein the chlorination reaction temperature in step 4) is 700-1200 ℃.

Technical Field

The invention relates to a method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate, belonging to the field of rare material recovery and re-preparation.

Background

The tantalum pentachloride is a white crystal with the boiling point as low as 242 ℃, and is beneficial to realizing the separation from impurity elements such as silicon, aluminum, titanium, iron, calcium, manganese, nickel and the like by utilizing the difference between the boiling point and the impurity element chloride. As an important precursor of ultra-fine high-purity tantalum powder and a high-purity tantalum coating, the precursor is widely applied to the fields of capacitors, artificial bones, ultra-high temperature materials and high corrosion-resistant materials; niobium pentachloride is a light yellow crystal with the boiling point as low as 250 ℃, is an important precursor of superfine high-purity niobium powder and a high-purity niobium coating, and is mainly applied to the fields of superconducting materials, corrosion-resistant and high-temperature-resistant high-performance materials and the like; lithium chloride is an inorganic compound of lithium, can be widely applied to the field of lithium battery materials, and also can be used as a soldering flux, a drying agent and the like in the field of air conditioning.

At present, tantalum/niobium pentachloride and lithium chloride are prepared by pure substances of tantalum/niobium and lithium, the tantalum/niobium and the lithium are important strategic resources and energy materials of the country, and resource exhaustion caused by mining and smelting of primary mineral resources is an important factor for limiting development of key fields of the country.

The common recovery method of the waste tantalum/lithium niobate introduces new substances such as aluminum or sodium and the like by a pyrogenic method and a wet method. The purity of the metal tantalum/niobium prepared by the pyrogenic process is low, a tantalum/niobium rod with relatively high purity can be obtained only by high-temperature electron beam melting, subsequent process treatment such as powder hydrogenation and the like is needed, the process flow is long, the energy consumption is high, and high-quality extraction of lithium is difficult to realize; the wet method adopts high-temperature alkali fusion, water washing and acid washing, the water consumption is large, the purity of the separated tantalum/niobium is only 98 percent, and the purity of the lithium is only about 96 percent. The traditional method for recovering the waste tantalum/lithium niobate only realizes the reclamation of the tantalum/niobium and the lithium and is difficult to realize the high-quality application of the tantalum/niobium and the lithium. Therefore, it is very important to develop a method for preparing high-purity tantalum/niobium pentachloride and lithium chloride from waste tantalum/lithium niobate with high quality.

Disclosure of Invention

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for preparing high purity tantalum/niobium pentachloride and lithium chloride; the invention realizes the high-quality recovery of the waste tantalum/lithium niobate and the preparation of the high-purity tantalum/niobium pentachloride and the lithium chloride, saves resources, and has no obvious increase of energy compared with the traditional high-purity tantalum/niobium pentachloride preparation method.

The invention relates to a method for preparing high-purity tantalum pentachloride and lithium chloride from waste lithium tantalate or preparing high-purity tantalum pentachloride and lithium chloride from waste lithium niobate, which comprises the following steps:

1) pretreatment of waste tantalum/lithium niobate

And washing the waste lithium tantalate/lithium tantalate particles by pure water and hydrochloric acid to remove surface impurity ash, and drying for later use.

2) Pretreatment of carbon source

Crushing the carbon source to more than 100 meshes, washing with pure water and hydrochloric acid to remove impurities, and drying for later use.

3) Material mixing and activation

Mixing the waste tantalum/lithium niobate obtained in the step 1) and the carbon source obtained in the step 2), and then carrying out plasma activation to break the crystal structure of the tantalum/lithium niobate and realize the grain refinement and carburization.

4) Chlorination reaction

Putting the waste tantalum/lithium niobate and carbon mixed material prepared in the step 3) into a chlorination furnace, vacuumizing the chlorination furnace and replacing with argon, finally introducing high-purity chlorine when the temperature of the chlorination furnace is raised to above 700 ℃, allowing the mixed material to perform chlorination reaction, allowing the generated tantalum/niobium pentachloride and carbon oxide to enter a high-temperature dust removal section with the temperature of above 400 ℃ in the form of steam, removing carried tantalum/lithium niobate, carbon and lithium chloride-free dust, cooling the gas to 255-plus-material temperature of 300 ℃, entering a filtering and iron-removing section to remove ferrous chloride, cooling the gas to 150-plus-material temperature of 220 ℃ in a material receiving section, and collecting the cooled and crystallized tantalum/niobium pentachloride powder, wherein the purity of the tantalum/niobium pentachloride is not less than 99.7%.

5) Lithium chloride separation

Washing the residual residue in the step 4) and the dust in the high-temperature dust removal section by pure water, dissolving the generated lithium chloride in an aqueous solution, and concentrating and crystallizing to obtain the lithium chloride powder with the purity of not less than 99.7%.

The invention breaks the crystal structure and material composition of the tantalum/lithium niobate by plasma carburization of the waste tantalum/lithium niobate, enhances the activation energy of the tantalum/lithium niobate, reduces the chlorination difficulty in the later period, removes dust at high temperature and iron at medium temperature in the collection stage of the gas product, directly separates high-boiling-point substances such as lithium chloride, ferric chloride, tantalum/lithium niobate, carbon powder, nickel chloride and the like from the tantalum/niobium pentachloride, does not need secondary purification of the tantalum/niobium pentachloride, and realizes the separation of the tantalum/niobium pentachloride and low-boiling-point substances such as silicon chloride, titanium chloride, aluminum chloride and the like by the heat preservation control of the material collection stage. Lithium chloride mainly stays in a chlorination furnace, liquid lithium chloride after slag discharge can be rapidly agglomerated and solidified to be separated from most unreacted carbon and a small amount of lithium tantalate, separation of lithium chloride is realized through water dissolving, and high-purity lithium chloride is obtained through concentration and crystallization.

The invention realizes the high-quality recovery of the waste tantalum/lithium niobate and the synergistic preparation of the high-purity tantalum/niobium pentachloride and the lithium chloride. On one hand, the invention overcomes the problems that the traditional waste lithium tantalate can only be simply recycled, the product purity and recovery rate are not high, and the process is complex, the reaction activation energy of the tantalum/lithium niobate is improved through the plasma carburization of the tantalum/lithium niobate, the chlorination reaction temperature and the reaction difficulty are reduced, the tantalum/lithium niobate can be basically and completely reacted and recovered, and the obtained products are high-purity tantalum/niobium pentachloride and lithium chloride. On the other hand, a novel method for preparing the high-purity tantalum/niobium pentachloride and the lithium chloride in a synergistic mode is developed, impurities of waste tantalum/lithium niobate are mainly on the surface, the surface cleaning of the tantalum/lithium niobate is realized through water washing and acid washing, the tantalum/lithium niobate can be used as a raw material for preparing the high-purity tantalum/niobium pentachloride and the lithium chloride, the reduction of high-boiling-point impurities in the tantalum/niobium pentachloride is realized through high-temperature dust removal and medium-temperature iron removal sections, the high-purity tantalum/niobium pentachloride is obtained in one step, meanwhile, the lithium chloride generated by the reaction is easily soluble in water and high in solubility in water, and can be simply separated from the unreacted tantalum/lithium niobate and carbon, and the high-purity lithium chloride is obtained through. In conclusion, the scheme of the invention has the advantages of simple operation, short flow, less energy consumption, low cost and environmental friendliness, is beneficial to the maximum utilization of resources and meets the requirement of industrial development.

Drawings

FIG. 1 is a process flow diagram of the present invention.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The following examples are intended to further illustrate the present disclosure and not to limit the scope of the claims.

Example 1

Weighing a certain amount of waste lithium tantalate, washing with 1 time of water by mass and 1 time of diluted hydrochloric acid with the mass fraction of 2%, washing with 1 time of water by mass, drying at 120 ℃, weighing a proper amount of activated carbon, crushing to 200 meshes, washing with 1 time of water by mass and 1 time of diluted hydrochloric acid with the mass fraction of 2%, washing with 1 time of water by mass, drying at 120 ℃, mixing with the treated lithium tantalate in a mixer for 10min, activating with 50kW plasma for 10min, feeding into a fluidized bed furnace for chlorination, wherein the molar ratio of the waste lithium tantalate, the activated carbon and chlorine is 1:2:3.5, the feeding rate of the waste lithium tantalate is 500 g/receiving min, the reaction temperature is 700-, after the fluidized bed furnace is cooled, lithium chloride blocks in the residues and dust in a high-temperature dust removal section are collected and washed and filtered by pure water of 20 times, the purity of the lithium chloride after concentration and crystallization is 99.68%, the content of impurity elements such as nickel, manganese, copper and the like is lower than 50ppm, the content of other impurity elements is lower than 20ppm, the tantalum recovery rate is 98.5%, and the lithium recovery rate is 98.3%.

Example 2

Weighing a certain amount of waste lithium niobate, washing with 2 times of water by mass, washing with 2% of dilute hydrochloric acid by 2 times of mass, washing with 2 times of water by mass, drying at 120 ℃, weighing a proper amount of activated carbon, crushing to 250 meshes, washing with 2 times of water by mass, washing with 2% of dilute hydrochloric acid by 2 times of mass, washing with 2 times of water by mass, drying at 120 ℃, mixing with the treated lithium niobate in a mixer for 15min, activating for 10min by transferring to 55kW plasma, chlorinating in a fluidized bed furnace, feeding hydrogen into an iron removal section, wherein the molar ratio of the waste lithium niobate, the activated carbon and chlorine is 1:2.5:4, the feeding speed of the waste lithium niobate is 500g/min, the reaction temperature is 800-, the contents of elements such as silicon, aluminum and the like are all lower than 20ppm, lithium chloride blocks in the residues and dust in a high-temperature dust removal section are collected after the boiling furnace is cooled and are washed and filtered by 20 times of pure water, the purity of lithium chloride after concentration and crystallization is 99.72%, the contents of impurity elements such as nickel, manganese, copper and the like are lower than 45ppm, the contents of other impurity elements are lower than 20ppm, the recovery rate of tantalum is 98.8%, and the recovery rate of lithium is 98.4%.

Example 3

Weighing a certain amount of waste lithium tantalite, washing with 2 times of water by mass, washing with 2% of dilute hydrochloric acid by 2 times of mass, washing with 2 times of water by 2 times of mass, drying at 120 ℃, weighing a proper amount of activated carbon, crushing to 350 meshes, washing with 2 times of water by 2 times of mass, washing with 2% of dilute hydrochloric acid by 2 times of mass, washing with 2 times of mass, drying at 120 ℃, mixing with the treated lithium tantalite in a mixer for 15min, activating with 60kW plasma for 20min, feeding into a fluidized bed furnace for chlorination, feeding hydrogen into an iron removal section, wherein the molar ratio of the waste lithium tantalite, the activated carbon and chlorine is 1:3:5, the feeding rate of the waste lithium tantalite is 500g/min, the reaction temperature is 800-plus materials, the temperature of a high-temperature dust removal section is controlled at 450 ℃, the temperature of the iron removal section is controlled at 260 ℃, the temperature of a material receiving section is controlled at 195 ℃, the obtained pentachloride tantalum, the content of elements such as silicon, aluminum and the like is lower than 20ppm, lithium chloride blocks in the residues and dust in a high-temperature dust removal section are collected after the residues are cooled by a fluidized bed furnace and are washed and filtered by 20 times of pure water, the purity of lithium chloride after concentration and crystallization is 99.75%, the content of impurity elements such as nickel, manganese, copper and the like is lower than 45ppm, the content of other impurity elements is lower than 20ppm, the recovery rate of tantalum is 98.9%, and the recovery rate of lithium is 98.8%.

Example 4

Weighing a certain amount of waste lithium niobate, washing with 2 times of water by mass, washing with 2% of dilute hydrochloric acid by 2 times of mass, washing with 2 times of water by mass, drying at 120 ℃, weighing a proper amount of activated carbon, crushing to 350 meshes, washing with 2 times of water by mass, washing with 2% of dilute hydrochloric acid by 2 times of mass, washing with 2 times of water by mass, drying at 120 ℃, mixing with the treated lithium niobate in a mixer for 15min, activating with a 60kW plasma for 20min, feeding into a fluidized bed furnace for chlorination, feeding hydrogen into an iron removal section, controlling the molar ratio of the waste lithium niobate, the activated carbon and chlorine to be 1:4:6:0.005, feeding the waste lithium niobate at a feeding rate of 500g/min, reacting at 1000-, the content of elements such as silicon, aluminum and the like is lower than 20ppm, lithium chloride blocks in the residues and dust in a high-temperature dust removal section are collected after the residues are cooled by a fluidized bed furnace and are washed and filtered by 20 times of pure water, the purity of lithium chloride after concentration and crystallization is 99.75%, the content of impurity elements such as nickel, manganese, copper and the like is lower than 45ppm, the content of other impurity elements is lower than 20ppm, the recovery rate of tantalum is 99.2%, and the recovery rate of lithium is 99.1%.