阅读说明：本技术 一种以电解精炼钛的电解质为原料制备TiN的方法 (Method for preparing TiN by taking electrolyte for electrorefining titanium as raw material ) 是由 邓斌 穆天柱 彭卫星 于 2019-10-14 设计创作，主要内容包括：本发明涉及钛资源回收技术领域,公开了一种以电解精炼钛的电解质为原料制备TiN的方法。该方法包括以下步骤：(1)在850-1000℃的温度下,将电解精炼钛的电解质在密闭反应器中进行减压蒸馏；(2)向步骤(1)的所述密闭反应器中通入N<Sub>2</Sub>,使所述密闭反应器内的气体压力升高至0.05-0.1MPa,在于步骤(1)相同的温度下,保温保压反应。本发明所述的方法具有操作简单、易控制等技术优势,可以有效的实现Ti电解精炼的电解质中Ti资源的回收利用,相对酸洗回收工艺,Ti回收率提高18-45％,获得纯度99.9％以上的TiN。(The invention relates to the technical field of titanium resource recovery, and discloses a method for preparing TiN by taking electrolyte of electrolytic refining titanium as a raw material. The method comprises the following steps: (1) carrying out reduced pressure distillation on the electrolyte of the electrolytic refining titanium in a closed reactor at the temperature of 850-1000 ℃; (2) introducing N into the closed reactor in the step (1) 2 And (3) raising the gas pressure in the closed reactor to 0.05-0.1MPa, and carrying out heat preservation and pressure maintaining reaction at the same temperature in the step (1). The method has the technical advantages of simple operation, easy control and the like, can effectively realize the recycling of Ti resources in the electrolyte of Ti electrorefining, improves the Ti recovery rate by 18-45 percent compared with the acid pickling recovery process, and obtains TiN with the purity of more than 99.9 percent.)

1. A method for preparing TiN by taking electrolyte for electrorefining titanium as raw material is characterized by comprising the following steps:

(1) carrying out reduced pressure distillation on the electrolyte of the electrolytic refining titanium in a closed reactor at the temperature of 850-1000 ℃;

(2) introducing N into the closed reactor in the step (1)₂And (3) raising the gas pressure in the closed reactor to 0.05-0.1MPa, and carrying out heat preservation and pressure maintaining reaction at the same temperature in the step (1).

2. The method of claim 1, wherein in the electrolyte for electrorefining titanium, Ti²⁺Is 0<Ti²⁺≤20wt％，Ti³⁺Is 0<Ti³⁺Not more than 20 wt%, Ti content not less than 0 and not more than 25 wt%, and the balance of alkali metal chloride.

3. The process according to claim 2, wherein the alkali metal chloride is sodium chloride to potassium chloride in a molar ratio of 1: 0.9-1.1.

4. The process according to claim 3, wherein the alkali metal chloride is sodium chloride to potassium chloride in a molar ratio of 1: 1.

5. The method according to any one of claims 2 to 4, wherein in the electrolyte for electrorefining titanium, Ti is present²⁺And Ti³⁺The sum of the concentrations of (A) and (B) is 5-10 wt%.

6. The method according to any one of claims 2 to 4, wherein in the electrolyte for electrorefining titanium, Ti is present²⁺、Ti³⁺And the sum of the contents of metallic titanium is 10 to 20 wt%.

7. The process according to any one of claims 1 to 4, wherein in step (1), the pressure of the reduced pressure distillation is 0.1 to 15 Pa.

8. The process according to any one of claims 1 to 4, wherein in step (2), the reaction time is 0.5 to 5 hours.

Technical Field

The invention relates to the technical field of titanium resource recovery, in particular to a method for preparing TiN by taking electrolyte of electrolytic refining titanium as a raw material.

Background

An electrolyte for refining titanium by molten salt electrolysis uses an alkali metal or alkaline earth metal halide mixture and adds a certain amount of low valent ions thereto.

Taking the case of an equimolar ratio of NaCl-KCl molten matrix electrolyte, TiCl is generally used for the preparation of the electrolyte₄Reacting with titanium sponge in molten salt, adding a certain amount of low valence titanium ions, mainly comprisingThe following reactions:

Ti+3TiCl₄＝4TiCl₃

Ti+TiCl₄＝2TiCl₂

TiCl₂+TiCl₄＝2TiCl₃

Ti+2TiCl₃＝3TiCl₂

during the preparation, the TiCl exists in the prepared electrolyte because the above reactions occur simultaneously and the rate and degree of each reaction cannot be accurately controlled₂Also having TiCl₃。

And TiCl₂With TiCl₃Disproportionation reaction can be carried out in the molten salt to generate micron-sized metal Ti powder and TiCl₄The electrolyte used for molten salt electrolytic refining of Ti needs to be replaced after a plurality of cycles of use, and the replaced electrolyte contains fine Ti powder and TiCl₂With TiCl₃When titanium-containing component is contained, the titanium powder is obtained by filtering and separating after the titanium-containing component is leached by dilute hydrochloric acid aqueous solution in the traditional technology, in the process, TiCl is used₂With TiCl₃The titanium powder is difficult to recycle after being dissolved into the aqueous solution, the total titanium recovery rate is lower than 60 percent, and the obtained titanium powder is seriously oxidized due to the fine particle size, so the technology can not effectively recycle the titanium resource.

Disclosure of Invention

The present invention has been made to overcome the above problems occurring in the prior art, and an object of the present invention is to provide a method for preparing TiN from an electrolyte for electrorefining titanium, which can effectively recycle Ti resources in the electrolyte for electrorefining titanium.

In order to achieve the above object, the present invention provides a method for preparing TiN using an electrolyte for electrorefining titanium as a raw material, comprising the steps of:

(1) carrying out reduced pressure distillation on the electrolyte of the electrolytic refining titanium in a closed reactor at the temperature of 850-1000 ℃;

(2) introducing N into the closed reactor in the step (1)₂Raising the gas pressure in the closed reactor to 0.05 to 0.1MPa in the step (a)1) And (5) keeping the temperature and the pressure for reaction at the same temperature.

Optionally, in the electrolyte for electrorefining titanium, Ti²⁺Is 0<Ti²⁺≤20wt％，Ti³⁺Is 0<Ti³⁺Not more than 20 wt%, Ti content not less than 0 and not more than 25 wt%, and the balance of alkali metal chloride.

Optionally, the alkali metal chloride is sodium chloride and potassium chloride in a molar ratio of 1: 0.9-1.1.

Optionally, the alkali metal chloride is sodium chloride and potassium chloride in a molar ratio of 1: 1.

Optionally, in the electrolyte for electrorefining titanium, Ti²⁺And Ti³⁺The sum of the concentrations of (A) and (B) is 5-10 wt%.

Optionally, in the electrolyte for electrorefining titanium, Ti²⁺、Ti³⁺And the sum of the contents of metallic titanium is 10 to 20 wt%.

Optionally, in the step (1), the pressure of the reduced pressure distillation is 0.1-15 Pa.

Optionally, in the step (2), the reaction time is 0.5-5 h.

The technical scheme of the invention has the beneficial effects that:

compared with the traditional acid washing recovery technology, the method for preparing TiN by taking the electrolyte of the electrolytic refining titanium as the raw material adopts the reduced pressure distillation separation, and TiCl is separated in the process₂With TiCl₃The efficient disproportionation reaction is carried out to generate titanium powder, the titanium powder is kept in distillation residues, the problem that part of titanium resources in the traditional technology cannot be effectively recycled due to entering of aqueous solution is solved, and the recovery rate of Ti resources in the electrolyte is improved by about 18-45%.

Furthermore, the titanium powder obtained in the closed vacuum distillation vessel is free from O₂Secondary oxidation, the titanium powder has higher activity and is directly reacted with N₂Preparing TiN by reaction, compared with the traditional method that finished metallic titanium powder and N are used₂The TiN preparation has lower reaction temperature and shorter reaction time, and the resource recovery cost is reduced by about 30 percent. Meanwhile, the micron-sized TiN also has higher economic utilization value and is relatively wetThe method recovery technology greatly improves the economic utilization value of the recovered product.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The method for preparing TiN by taking electrolyte of electrolytic refining titanium as a raw material comprises the following steps:

(1) carrying out reduced pressure distillation on the electrolyte of the electrolytic refining titanium in a closed reactor at the temperature of 850-1000 ℃;

(2) introducing N into the closed reactor in the step (1)₂And (3) raising the gas pressure in the closed reactor to 0.05-0.1MPa, and carrying out heat preservation and pressure maintaining reaction at the same temperature in the step (1).

In this context, pressure refers to absolute pressure.

According to the process of the invention, for pure TiCl₃In other words, there are the following two disproportionation reactions, reaction (1) and reaction (2), respectively:

4TiCl₃＝3TiCl₄(g)+Ti (1)

2TiCl₃＝TiCl₄(g)+TiCl₂(2)

likewise, TiCl₂There are also two disproportionation reactions, reaction (3), reaction (4), respectively:

2TiCl₂＝Ti+TiCl₄(g) (3)

3TiCl₂＝Ti+2TiCl₃(4)

the gibbs free energies of the above reactions are:

ΔG⁰ ₍₁₎＝-0.4369T+418.46kJ·mol^-1(670≤T<1000℃)

ΔG⁰ ₍₂₎＝-0.1328T+112.8kJ·mol^-1(670≤T<1000℃)

ΔG⁰ ₍₃₎＝-0.1714T+192.87kJ·mol^-1(670≤T<1000℃)

ΔG⁰ ₍₄₎＝-0.0471T+86.869kJ·mol^-1(670≤T<1000℃)

the calculation result shows that the reactions (1) and (2) can occur only when the temperature is respectively higher than 880 ℃ and 980 ℃ under normal pressure, and the reactions (3) and (4) have delta G >0 under normal pressure, so that the occurrence possibility is not high, but the step (1) adopts reduced pressure distillation, and the calculation formula of the Gibbs free energy of the reactions is as follows under the negative pressure condition:

ΔG＝ΔG⁰+RTln(p/p⁰) (5)

wherein Δ G is the Gibbs free energy of reaction, kJ. mol^-1；ΔG⁰In order to react the standard Gibbs free energy, kJ. mol^-1(ii) a R is a gas constant of 8.314X 10^-3kJ·(mol·K)^-1(ii) a T is temperature, K; p is system pressure, Pa; p is a radical of⁰Is at standard atmospheric pressure, 1.01X 10⁵Pa。

According to the calculation result of the formula (5), the reactions (2), (3) and (4) can all occur in the temperature range under the pressure lower than 15Pa, and the reaction (1) can occur at the temperature higher than 800 ℃. And the system pressure is 0.1-15Pa, the temperature is 850-1000 ℃, the reaction (2) is easier to occur than the reaction (1) and the reaction (3) is easier to occur than the reaction (1) at the same temperature, so that in order to control the reactions (2) and (3) mainly occurring in the step (1), the temperature range of the step (1) needs to be controlled to be 850-1000 ℃, and the reaction cannot occur due to overhigh system pressure, so that the reaction temperature and the system pressure range need to be controlled in order to improve the recovery rate of Ti chloride in the electrolyte.

In the step (1), the pressure of the reduced pressure distillation is preferably 0.1 to 15 Pa.

According to the inventionIn the step (1), the electrolyte for electrorefining titanium is in a molten state. In the initial molten electrolyte, Ti²⁺May be 0<Ti²⁺≤20wt％，Ti³⁺May be 0<Ti³⁺Not more than 20 wt%, Ti not more than 0 and not more than 25 wt%, and the balance of alkali metal chloride. The alkali metal chloride can be sodium chloride and potassium chloride in a molar ratio of 1: 0.9-1.1. Preferably, the alkali metal chloride is sodium chloride and potassium chloride in a molar ratio of 1: 1.

In the electrolyte for electrorefining titanium, preferably, Ti²⁺And Ti³⁺The sum of the concentrations of (A) and (B) is 5-10 wt%.

In the electrolyte for electrorefining titanium, preferably, Ti²⁺、Ti³⁺And the sum of the contents of metallic titanium is 10 to 20 wt%.

According to the method of the invention, in the step (1), alkali metal chloride, such as NaCl and KCl, is gasified and volatilized into a condenser of a distillation device and condensed into a solid state to be separated, and original titanium powder is remained in a distillation residue.

According to the process of the present invention, in step (2), the reaction time is preferably 0.5 to 5 hours. For the step (2), the gas pressure and the pressure maintaining time need to be controlled to obtain a better nitriding effect, and the time is too long, the temperature is too high, and the energy consumption is not good.

Through the technical scheme, the method for preparing TiN by taking the electrolyte of the electrolytic refining titanium as the raw material has the technical advantages of simple operation, easy control and the like, can effectively realize the recycling of Ti resources in the electrolyte of the electrolytic refining titanium, improves the Ti recovery rate by 18-45 percent compared with the acid washing recovery process, and can obtain TiN with the purity of more than 99.9 percent.

The present invention will be described in detail below by way of examples, but the scope of the present invention is not limited thereto.