JP2009132960A - Separation and refining process by chloride volatilization - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separation and refining process by chloride volatilization by which a process capable of producing an unconventionally high separation efficiency can be provided by combining a control of a cooling temperature field and an extraction step with chloride volatilization. <P>SOLUTION: A first step is a chlorination treatment step where raw materials are heated in a chlorine-air flow and respective elements are chlorinated to undergo separation and volatilization to produce a high-concentration chloride vapor. A second step is a separation and concentration step where the elements released as chlorides are isolated using changes in the boiling point and the chlorides separated from raw material powder are precipitated by the regulation of temperature in a cooling section to carry out separation of simple substances with respect to the respective elements. A third step is an extraction step where the high-concentration solid chlorides after the separation of simple substances are immersed in a solvent such as ether to perform selective separation of indium. The second step and/or the third step can be combined with the first step. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a method for converting an element such as indium contained in a raw material containing a rare metal, that is, scrap containing a plurality of compounds into metal chloride, and separating the element by using temperature control and solvent extraction treatment in combination. The present invention relates to a separation and purification method by a volatilization method.

Currently, rare metals such as indium, which are indispensable as raw materials for functional materials, are low in absolute amount and are expensive, so various secondary resources such as ITO target scraps, scraps, and cutting powder during processing. Attempts have been made to separate and extract by a wet method for the purpose of recovery from sewage.
As a general wet processing method, there are a method in which dissolution with hydrochloric acid or nitric acid and solvent extraction are combined, and a method in which the concentration of elements such as indium is increased by repeating dissolution with acid and precipitation with alkali.
Specifically, for example, an indium-containing starch is produced by dissolving the raw material with hydrochloric acid or nitric acid and then making it a strong alkali, and after solid-liquid separation, this is dissolved with sulfuric acid or mixed acid, and added with a metal species to precipitate. A method of recovering indium has been studied (see Patent Documents 1 and 2).

However, these methods mainly deal with ITO sputtering targets containing tin and indium at a high concentration, and include many metal species such as ores and polishing powders, and are used as raw materials with low indium content. It is not compatible. In addition, since it is necessary to repeat the liquid treatment process many times, an increase in wastewater treatment cost becomes a problem.
As another method, in order to finally recover high-purity metallic indium, the indium-containing raw material is dissolved in hydrochloric acid, added with alkali, precipitated as a hydroxide, and then coexisted by blowing hydrogen sulfide. A method for removing elements, that is, metal species harmful to the electrolytic process is disclosed (see Patent Document 3).
However, each method requires a multi-stage extraction process using several kinds of solvents. Therefore, the multi-stage process accompanying the diversification of raw materials and the increase in waste liquid treatment costs are inevitable issues. .

On the other hand, there have been some reports on dry separation methods of rare metals using chloride volatilization reaction, but most of them have been limited to model experiments for oxides and simple tracking of volatilization behavior. Experiments related to scrap are also simply tracking the volatilization behavior (see Non-Patent Documents 1 and 2). In addition, there has been no research report on dry separation of indium that has begun to attract attention in recent years.
For this reason, an efficient method for separating and purifying indium by a dry process has not yet been put into practical use.

JP 2007-39798 A JP 2002-69684 A JP 2007-131953 A F. Yung, V. Hlavacek: Powder Technology 102 (1999) 177-183 N.V.Manukyan, V.H.Martirosyan: Journal of Materials Processing Technology 142 (2003) 145-151

  In order to increase the extraction efficiency and yield of indium by the chloride volatilization method, the present invention combines the control of the cooling temperature field and the extraction step with a solvent such as ether, to achieve a low concentration that has not been targeted by the conventional method. This is a separation and purification method based on the chloride volatilization method that provides a process that can handle unprecedented separation efficiencies.

  The invention according to claim 1 is a chloride volatilization treatment step of heating a raw material in which a plurality of compounds are mixed in a chlorine stream, performing volatilization separation using a change in boiling point, and producing a high concentration chloride vapor, It relates to a separation and purification method by a chlorination volatilization method having a separation and concentration step in which high-concentration chloride vapor is deposited by adjusting the temperature of the cooling zone using the difference in freezing point and each element is separated as a high-concentration solid chloride. These are a method for producing high-concentration chloride vapor using the difference in reactivity with the chlorinating agent, and a method for separating and concentrating chloride by controlling the cooling temperature field using the difference in freezing point.

  The invention according to claim 2 further includes an extraction step of selectively separating each element by immersing the high-concentration solid chloride separated in the separation and concentration step with a solvent. This is a separation and purification method based on the method, separation and concentration of chloride by controlling the cooling temperature field using the difference in freezing point, and extraction process that performs selective separation of chloride using the difference in solubility in ethers and other solvents. This is a separation and production method.

  The invention described in claim 3 further includes an extraction step of selectively separating each element by immersing the high-concentration chloride vapor volatilely separated in the chlorination volatilization treatment step of claim 1 with a solvent. This is a separation and purification method based on the chlorination volatilization method described above. Selective separation of chloride is performed using the difference in solubility in a solvent such as ether directly against high-concentration chloride vapor utilizing the difference in reactivity with the chlorinating agent. This is a separation and production method that includes an extraction process.

  Further, the invention according to claim 4 is a chlorinated volatile solution in which a raw material in which a plurality of compounds containing indium are mixed is heated in a chlorine stream, and volatile separation of indium, titanium, chromium and iron is performed to produce a high concentration chloride vapor. This is a separation and purification method by a chlorination volatilization method comprising a treatment step and a separation and concentration step in which each element is separated as a high-concentration solid chloride by depositing by adjusting the temperature of the cooling zone using the difference in freezing point, This is a method for producing high-concentration chloride vapor using the difference in reactivity with the agent, and a method for efficiently separating and concentrating indium as chloride by controlling the cooling temperature field using the difference in freezing point.

  The invention according to claim 5 further comprises an extraction step in which selective separation of indium is performed by further immersing the high-concentration solid chloride separated in the separation and concentration step with ether. Separation and purification method by the separation of the chloride by the control of the cooling temperature field using the difference in freezing point, and the extraction process that performs the selective separation of indium chloride using the difference in solubility in ether It is a generation method.

  The invention described in claim 6 further includes an extraction step for selectively separating indium by further immersing the high-concentration chloride vapor volatilely separated in the chlorination volatilization treatment step in claim 4 with ether. Extraction process that separates and purifies indium chloride using the difference in solubility in ether directly against high-concentration chloride vapor using the difference in reactivity with the chlorinating agent. It is the separation production method which goes through.

  As described above, according to the present invention, after reacting a chlorine-containing gas with various raw materials containing indium, by using the control of the cooling temperature field and the ether extraction together, Elements such as indium can be selectively separated and purified from the inside. As a result, the number of processes is reduced, and it is possible to reduce equipment costs when utilizing elements such as indium from various raw materials and to utilize various unused resources.

The present inventor has studied various methods for the purpose of solving the above-described problems.
As a result, (1) When the raw material powder is heated in a chlorine stream, the volatility of indium is thermodynamically indium trichloride at high temperatures, and it volatilizes as chlorides of different valences at lower temperatures. (2) The coexisting elements contained in the raw material have different reactivities with the chlorinating agent depending on the form, and only some metal species can be separated by the chlorination volatilization reaction, (3) the volatilized metal chloride is Obtaining the knowledge that it can be isolated by adjusting the temperature distribution in the cooling zone, and (4) that indium chloride can be selectively extracted by immersing the high-concentration chloride solid produced by the chloride volatilization reaction with ether. Has reached

The conditions necessary for the present invention, which is characterized by efficiently extracting indium from the indium-containing raw material, are described below.
(1) Almost all indium present in various compound forms including ores and reagents can be used, and in particular, it can be used for separation and purification of indium, titanium, iron, chromium, silicon, aluminum, and carbon.
(2) Although it is desirable that the purity of chlorine gas used as a chlorinating agent is high, a mixed gas with nitrogen gas can also be used.
(3) As a solvent for extraction, ethers such as diethyl ether can be used. However, the leaching rate with respect to each element differs depending on the type, and the leaching rate may decrease with some solvents.

  The present invention will be described more specifically with reference to the following examples. Here, when selectively separating indium from various raw materials, as an example of high efficiency and high extraction rate, it consists of a simple composition such as carbide and oxide, and does not include complex complex oxides. The polishing powder discharged from the manufacturing process of the electronic material was taken as an example. The present invention is not limited to these.

  An example of the overall flow of the present invention is shown in FIG. The first process consisting of each step shown in 1-3 is a chloride volatilization treatment process heat treatment process in which the raw material is heated in a chlorine stream, and volatile separation of indium, titanium, chromium, and iron is performed to create a high-concentration chloride vapor. The second process consisting of the steps shown in 4 is to isolate the rare metal element released as chloride using the change in boiling point, and adjust the temperature of the cooling section of the metal chloride separated from the raw material powder. In the third step consisting of the separation and concentration step of depositing and isolating each element, and the steps shown in 5 to 7, the selection of indium is performed by immersing the single-concentrated high-concentration solid chloride with a solvent such as ether. It is an extraction process for performing separation.

In Steps 1 to 3, the raw material is chlorinated and high-concentration chloride vapor is generated. As the raw material, polishing powder discharged from the manufacturing process of the electronic material was used. In addition to In, the raw material contains Ti, Fe, Cr, Al, and Si. In addition, Al ₂ O ₃ and SiC derived from the abrasive are contained in the raw material, and these coexisting elements present in a stable form have low reactivity with the chlorinating agent, so in this first step, chlorine By heating in an air stream, Al, Si and the like can be concentrated and separated into a solid phase.

For example, most of In, Ti, Cr, and Fe can be volatilized and separated into the gas phase by heating the sample in a chlorine gas stream at a heating rate of 30 ° C / min and a maximum temperature of 200 to 700 ° C. It was. An example of volatilization behavior of In, Cr, Ti, and Fe converted into chloride and released into the gas phase is shown in FIG. Here, assuming that the maximum amount of each metal that can be released from the raw material powder is 1.0, the ratio of the transition to the gas phase as the temperature rises is shown.
At this time, Ti, Fe, Cr, and In released into the gas phase move in the reactor as chloride vapor, and deposit with a certain distribution as the temperature decreases.
Thermodynamically, the form of each element released into the gas phase can be estimated as InCl ₃ , FeCl ₃ , TiCl ₄ , and CrCl ₃ , respectively, and by utilizing the difference in the deposition temperature, the chloride deposition distribution can be estimated. It is clear that each element can be selectively separated.

In step 4, high concentration chloride vapor is separated and concentrated. The chloride of each element released into the gas phase by the chlorination treatment in Step 2 precipitates and deposits particles in the gas cooling process. Since the deposition temperature of each chloride differs depending on the element, in the example of FIG. 1 by adjusting the cooling temperature field, Cr is CrCl ₃ , In is InCl ₃ , Fe is FeCl _3, and Ti chloride is TiCl _4. Each can be isolated as follows.

That is, in the cooling section, for example, chromium having a high boiling point is deposited as CrCl ₃ alone in a relatively high temperature region, and titanium chloride has a low boiling point and migrates in the low temperature region as deposited or in a gaseous state. Separable. Through the above operation, at least 90% or more of indium contained in the raw material powder can be selectively separated as chloride.

  In addition, when the chlorination process is performed without controlling the cooling temperature field in step 4, a concentrated solid containing, for example, about 78% of indium at the maximum can be obtained in the step indicated by 3. In this case, compared with the process in which the cooling temperature field in step 4 is controlled, the deposition region of each element overlaps widely, so that the separation rate from the coexisting elements decreases, and the ether extraction process in step 6 can be combined and recovered. Indium is about 63%.

  On the other hand, by controlling the cooling temperature field in the step indicated by 4, the overlap of the chloride deposition regions is reduced, and the indium recovery rate can be increased by 20% or more as the separation rate is improved. At the same time, most of the chromium contained in the raw material of this example can also be recovered as chloride. This process is also effective when the chlorine gas flow rate is changed, and the separation rate can be further improved by increasing the gas flow rate or combining it with the aforementioned operation.

  In the step indicated by 5, the solid chloride is further separated and concentrated by ether extraction. The concentrated solid chloride obtained in the separation step by controlling the cooling temperature field in step 4 can be selectively extracted by immersing it in a solvent such as ether. That is, in the extraction process, for example, when diethyl ether is used as a solvent, the extraction rate of indium chloride reaches 85% or more, but other chlorides only dissolve a part of iron, and titanium chloride or chromium chloride. Does not dissolve.

  That is, by utilizing the difference in solubility of chloride with respect to ether, In chloride can be selectively separated and extracted from the concentrated solid chloride obtained in Step 5. Chlorination treatment is performed at 600 ° C, chloride released into the gas phase is deposited and separated at around 400 ° C, and each solid chloride deposited in the high temperature region and the low temperature region is extracted with diethyl ether. By separating coexisting elements such as titanium and chromium from the powder, a concentrated solid containing at least 90% indium can be obtained.

  As described above, according to the present invention, for a high concentration chloride vapor obtained by heating in a chlorine stream against secondary resources including various indium compounds, control of the cooling temperature field, ether, etc. By using the extraction process used together, various indium compounds can be selectively separated and purified. The present invention is applied to a method for separating and purifying indium by the chloride volatilization method. More specifically, the present invention is a method including a chlorination treatment step in combination with control of the cooling temperature field and ether extraction, and efficiently converts indium compounds contained in various secondary resources into metal chlorides. This is a method for separation and purification.

It is a flowchart which shows typical embodiment of the separation and purification method by the chlorination volatilization of the indium from the raw material which concerns on this invention. In Example 1 of this invention, it is a figure which shows an example of the volatilization behavior of In, Ti, Cr, and Fe when a raw material is heated in a chlorine airflow.

Explanation of symbols

1 Raw materials (raw material supply process for secondary resources including various indium compounds)
2 First step (chlorination and chloride volatilization process)
3 High-concentration chloride vapor (Transition / precipitation process of high-concentration chloride vapor enriched with any element)
4 Second step (Separation and concentration step of chloride using cooling temperature field)
5 Third step (Extraction step of indium chloride with ether)
6 Indium compounds (indium compound storage step extracted in the third step)
7 Ether (extractant supply process such as ether)

Claims (6)

  A raw material containing a plurality of compounds is heated in a chlorine stream and volatile separation is performed using the change in boiling point to produce a high-concentration chloride vapor, and the high-concentration chloride vapor is converted into a freezing point. Separation and purification method by the chlorination volatilization method, which has a separation and concentration step in which the elements are separated as a high-concentration solid chloride by depositing by adjusting the temperature of the cooling section using the difference.   The separation and purification method according to the chlorination volatilization method according to claim 1, further comprising an extraction step of selectively separating each element by immersing the high-concentration solid chloride separated in the separation and concentration step with a solvent.   The separation purification method by the chlorination volatilization method according to claim 1, further comprising an extraction step of selectively separating each element by immersing the high concentration chloride vapor volatilely separated in the chlorination volatilization treatment step according to claim 1 with a solvent. .   Utilizing the difference between the freezing point and the chlorination volatilization process, which heats a raw material in which multiple compounds containing indium are mixed in a chlorine stream and performs volatile separation of indium, titanium, chromium and iron to produce high-concentration chloride vapor. And a separation / concentration method using a chlorination volatilization method, wherein the element is deposited by adjusting the temperature of the cooling section, and each element is separated as a high-concentration solid chloride.   The separation and purification method according to the chloride volatilization method according to claim 4, further comprising an extraction step of selectively separating indium by immersing the high-concentration solid chloride separated in the separation and concentration step with ether.   5. The separation and purification method by the chlorination volatilization method according to claim 4, further comprising an extraction step of selectively separating indium by immersing the high-concentration chloride vapor volatilely separated in the chlorination volatilization treatment step according to claim 4 with ether.