JPH044982B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for continuous production of niobium iodide.
More specifically, crude niobium metal is continuously supplied to a high temperature section and a large excess of solid iodine is continuously supplied to a low temperature section, and the niobium metal and iodine gas are reacted in the high temperature section to continuously generate iodide at a high rate. At the same time, by controlling the temperature of the collector, niobium iodide and trace impurity iodide are purified and separated by utilizing the precipitation temperature difference, and unreacted iodine is simultaneously purified in a distillation column connected to the reaction system.
This invention relates to a continuous, high-speed production system for high-purity niobium iodide that enables completely closed production of iodine by quenching it with an inert gas, recovering it as high-purity iodine powder that is easy to handle, and reusing it. Conventionally, metal iodides have generally been produced by a fluidized method or a closed method, but these methods have had the following drawbacks. Both the flow method and the sealed method are batch methods, which are not suitable for continuous production, and the production rate is very slow (about 10 to 24 hours are required to produce about 200 g). A separate purification step was required to further improve the purity of the produced iodide. Moreover, in distillation purification, iodides generally decompose at low temperatures when not in an iodine atmosphere and become nonvolatile lower iodides, so the above purification steps had to be carried out at low temperatures below the decomposition temperature of 200°C or under reduced pressure. Higher iodides were difficult to produce using the normal fluidization method. If unreacted iodine were recovered using a conventional trap, it would contain many impurities and would become an ingot, which would be extremely difficult to handle, and would require a separate iodine purification step. In addition, it was necessary for iodine to be completely closed for safety and health reasons. The purpose of the present invention is to easily obtain high-purity iodide used in the iodide thermal decomposition method as a means of obtaining high-purity metals. This eliminates the drawbacks of That is, in the present invention, crude metal niobium and iodine are continuously fed through a feeder (especially for iodine with poor fluidity, an electromagnetic feeder set in a closed chamber is preferable) and reacted.
The generated iodide is purified directly in the collector at normal pressure and low temperature due to the difference in precipitation temperature, and unreacted iodine is purified in a distillation column connected to the reaction system, and then rapidly cooled with a cooling inert gas. The present invention provides a method for continuously producing high-purity niobium iodide by recovering it as high-purity powdered iodine that is easy to handle and reusing it in the reaction system, thereby achieving a completely closed iodine system. The present invention provides a high-speed, continuous production apparatus for high-purity niobium iodide that eliminates all of the conventional problems at once. Next, the present invention will be specifically explained with reference to the accompanying drawings and examples. FIG. 1 shows an example of an apparatus for implementing the present invention. In the figure, 1 is an iodine pot for replenishment, which supplies consumed iodine as iodide. The iodine reservoir 2 is a sealed iodine feeder (for example, an electromagnetic feeder), which quantitatively supplies powdered iodine into the iodine vaporizer 4. The gaseous iodine here is sent to the reactor 5, supplied quantitatively from the crude niobium metal pot 6, and reacts with the crude niobium metal falling into the mezzara 7 to produce niobium iodide. The produced niobium iodide is 9
Only purified niobium iodide is collected in the collection pot for niobium iodide (No. 8), and unreacted iodine and impurity iodide enter the iodine distillation tower (No. 11) to collect impurities. Iodide enters pot 10 and purified iodine gas enters iodine quench trap 12 which is cooled by a refrigerant. Here, the iodine gas is rapidly cooled by an inert gas cooled by the cooler 13, turned into powder, and fed back to the iodine reservoir pot 2. High-purity niobium iodide is produced in conjunction, and the iodine is also safely closed. be converted into More specifically, the entire system is evacuated to 10 ^-2 _tprr or less,
Deaeration and dehydration are performed by heating to approximately 300℃ or higher and holding it for a long time. Next, an appropriate amount of iodine is supplied to an iodine vaporizer heated above its boiling point to create an iodine atmosphere in the entire system. Furthermore, after each part reaches a predetermined temperature, crude niobium metal is provided and iodinated. By the way, regarding the reaction temperature, the iodination reaction of crude niobium metal increases rapidly at temperatures above 300°C.
There is no particular restriction as long as it is above 300℃, but usually 400℃
~600℃ is adopted. The produced iodide enters the purification column 9 in gaseous form, but at this time, the partial pressure of excess iodine gas is extremely high, so the partial pressure of iodide is kept low, so that each iodide is Only iodides whose temperature in the purification column 9 is below the precipitation temperature are precipitated by partial pressure. Most of the trace impurity iodide does not precipitate because its partial pressure is very low, and leaves from the upper part of the purification column 9 along with unreacted iodine as a gas, thereby producing a purification effect. The temperature of each part of this purification column is determined by the composition of the fed gas, the desired purity of niobium iodide, and the allowable loss rate of niobium iodide. Unreacted iodine and impurity iodide are transferred to the iodine distillation column 11.
In this case, iodine may be introduced in either liquid or gas form. In the iodine distillation column 11, unreacted iodine and impurity iodide are purified while maintaining vapor-liquid equilibrium, and the purified iodine enters the iodine quenching pot as a gas. Each temperature within the iodine distillation column is also determined by the composition. The purified iodine gas is rapidly cooled with a cooled inert gas, pulverized, and reused. The refrigerant for iodine quench pot and inert gas cooling is
Any general refrigerant may be used, although there are no limitations, usually -50℃
By using a refrigerant that can be cooled below, better iodine powder can be produced. Examples are shown below.

[Table] The purification effects of niobium iodide and iodine produced under the above conditions are shown below.

[Table] The iodine bonding degree of the produced niobium iodide is shown below.

[Table] As described above, the advantages of the present invention are that high purity iodide can be produced continuously. The iodide produced can be co-distilled and the iodide obtained is a very high iodide. Unreacted iodine can also be distilled at the same time, and the process is completely closed as it is recovered as a powder and fed back. As a result, the iodide production rate was dramatically improved, iodine loss was minimized, and both productivity and economic efficiency were greatly improved.

[Brief explanation of drawings]

Figure 1 is a diagram showing one embodiment of the apparatus for implementing the present invention, in which 1 is a supplementary iodine tank, 2 is an iodine tank, 3 is an iodine charger, 4 is an iodine vaporizer, and 5 is a perforated plate. , 6 is a reactor, 7 is a metal niobium pot, 8 is a niobium iodide collection pot, 9 is a niobium iodide purification tower, 1
0 is an impurity iodide collection pot, 11 is an iodine distillation column, 12 is an iodine cooler, and 13 is an inert gas cooler.

Claims (1)

[Claims] 1 Metallic crude niobium and excess iodine are continuously supplied to the reaction system to produce niobium iodide, and the generated niobium iodide is separated into impurity iodide and niobium iodide by temperature control in a collector, and then further added to the reaction system. The unreacted iodine gas discharged from the reactor is distilled in a distillation column connected to the reaction system, and the purified iodine gas is pulverized by adiabatic expansion and/or contact with cooling gas, and reused in the reaction system to continuously increase the A method for producing high-purity niobium iodide, characterized by producing high-purity niobium iodide.