JPS60255601A - Method of chlorination in molten salt bath - Google Patents

Abstract

PURPOSE:To increase a reaction rate in a molten salt bath, by adding a metal whose higher chloride has strong chlorinating power or its chloride to the molten salt bath. CONSTITUTION:As a method to increase a reaction rate in a molten salt bath, a metal whose higher chloride has strong chlorinating power, such as Fe, Cr, Nb, Ta, Sn, V, Cu, or its chloride is added to the molten salt bath. By the addition, the reaction rate is extremely increased, it is considered that the rise in the reaction rate is due to a catalytic chlorinating reaction caused by the metal chloride besides direct chlorination with a chlorinating agent such as a chlorine gas, etc. In a catalytic reaction with a chlorine gas, an iron chloride is shown as an example, the chlorine gas is absorbed in the catalytic chloride as shown in the formula I and II, and spread in the whole bath, so lessening of chlorine gas bubbles as carried out conventionally is not required.

Description

[Detailed description of the invention] Concerning how to chlorinate which metal components.

More specifically, in the molten salt bath chlorination method, a metal capable of forming a higher chloride capable of chlorinating the target metal component, or a chloride thereof, is added to the molten salt bath as a chlorination catalyst. It is.

The method of obtaining metal chlorides by chlorinating metal-containing substances in a molten salt bath such as NaCI-KCI eutectic salt has been attempted for the chlorination of various metals because there is no local heating due to reaction heat and temperature control is easy. It is being (For example, Nanjo, Japan Mining Association,
1981 Spring Conference Lecture Abstracts P243) In this molten salt bath, in order to increase the reaction rate, it is generally necessary to finely grind the raw metal components and suspend them in the bath. However, some raw materials are difficult to suspend when finely pulverized, and even if they are suspended, it is necessary to use equipment such as mechanical stirring to improve the contact between the chlorinating agent such as chlorine gas and the raw materials. This is not necessarily a desirable method as it requires some ingenuity.

As a result of intensive study on methods for increasing the reaction rate in a molten salt bath, the present inventors found that the higher chloride of the metal has a strong chlorinating power, such as Fe.

Cr1Nb, Ta, Sn, V, Cu or
The present invention was completed by discovering that the reaction rate was dramatically increased by adding solerano chloride to a molten salt bath.

This increase in reaction rate is thought to be due to the fact that, in addition to direct chlorination using a chlorinating agent such as chlorine gas, a catalytic chlorination reaction occurs using the added metal chloride.

Next, the present invention will be described in detail.

The catalytic reaction using chlorine gas in the present invention will be explained below using chlorides of iron and chromium as examples. (H in the formula
is the target metal in the raw material, m is the coefficient) In the case of iron, mFecJt3 + H = H (Jll + mFec12
・' (1) IllFec4 +II+/2CJ2 =
ml'ec4-(2)m+(2)H+ m/2Cj
! 2= Hclm-(3) mcrcJ for chromium! ,,+H=MCI! III +mCrC
Jz ・(1)'mCrC4+ m/2Cmeng,, =
mcrcj! 3・(2)'(1)'+(2)' H+
m/2CJ! , = HC port (3)' Although such catalytic reactions have been known in aqueous systems or organic solvent systems, there are no examples of them being used in high-temperature reactions such as metal chlorination reactions.

In a typical dry high-temperature chlorination reaction, even if such a catalytic chloride is added, it will quickly vaporize and be lost, and the absence of a solvent will prevent smooth movement of the catalytic chloride, resulting in a loss of catalyst. It shows almost no effect.

On the other hand, in the present invention, the vapor pressure of the catalyst chloride dissolved in the molten salt bath generally decreases in proportion to the mole fraction in the molten salt bath, and vaporization loss is small even at temperatures above the boiling point of the chloride. It can be used satisfactorily, and the chloride moves quickly in the molten salt bath, so that it can sufficiently exhibit its catalytic action.

When Ha(J, Cλ, etc.) is used as the molten salt bath, the vapor pressure is further reduced by forming a double salt with the added chloride, so it can be used as a catalyst at higher temperatures.

In the present invention, the chlorinating agent used by blowing into the reaction system,
For example, since the chlorine-containing gas is absorbed by the chlorinated catalyst and spreads throughout the bath as shown in equations (1) and (2) above, there is no need for any equipment improvements to reduce the size of chlorine gas bubbles as in the conventional method.

In the present invention, the catalyst added as a chlorination catalyst may be in the form of a metal, a lower chloride, or a higher chloride. Even when added as a metal or lower chloride, the additive is chlorinated by a chlorinating agent and has a high
It becomes a chemical substance and exhibits catalytic action.

It is sufficient that the amount of the metal or its chloride added as a catalyst is 1101% or more in the molten salt bath, but it is preferably added in an amount of 5101% or more under conditions where there is no vaporization loss of the catalyst.

The reaction temperature in the present invention may be a temperature at which the higher chloride used as a catalyst can chlorinate the target metal, but it may be set at a temperature at which the higher chloride used as a catalyst is easily thermally decomposed (FeCj13
The catalytic action is most effective at temperatures above 300 degrees Celsius for CrC4 and about 600 degrees Celsius for CrC4.

Further, when the reaction is carried out at a temperature much higher than the boiling point of the catalyst chloride, it is preferable to reduce the catalyst concentration in order to prevent loss of catalyst by vaporization.

In the present invention, the metal to be chlorinated or the metal component such as a metal-containing substance may be any metal as long as it can be chlorinated by the higher chloride used as a catalyst, such as crude metals, alloys, metal sulfides, etc. Examples include metal compounds, metal scraps, and mixtures with ceramics such as waste catalysts.

In addition, the components used as the molten salt bath are those in periodicity group Ⅰ (L
i, Na, Ni, etc.) and Group 1I (140, Ca,
These are metal chlorides or fluorides of Ba, etc.), and these are used alone or as a mixed salt.

Next, the present invention will be explained in further detail with reference to Examples.

Example I LiCJ: KC Oni BaCj2 = 5:38 Near (
FeC
Using a molten salt bath containing 12.4 parts by weight of
0s ■ metal Si grains (Si: 98X or more) at 400 degrees C
, C12 gas flow 1100*I/sin.

A: As a result of chlorination using the equipment shown in Figure 1 at a gas flow rate of 100 m1/win, the chlorination rate of Si was 4Q.
/hr, and the product obtained in the condenser was 3iC& with a slight yellow tinge.

Further, the vaporization loss of Fe chloride from the molten salt bath was 1z or less.

Comparative Example 1 Si was chlorinated in the mixed chlorides of Example 1 and Shuichi under the same conditions as in Example 1 without adding an Fe compound, and the chlorination rate was O, 13 g/hr. In addition, as a result of filling only Si into the apparatus shown in Figure 1 without using a molten salt bath and chlorinating at the same temperature and gas flow rate as in Example 1, the chlorination rate was i.
, 1 g/hr.

Example 2 Using a molten salt bath in which 5 parts by weight of CrC was added to 10 parts by weight of a mixed salt of NaCl: to cjl = 1:1 (molar ratio), 3 Il 1 m at 750 to 800 degrees C and a C4 gas flow rate of 400 ml/min. When metallic chromium of the following size was chlorinated for 45 minutes using the apparatus shown in Figure 2, the average chlorination rate was 40(]/hr, and
The average chlorination rate when chlorinated for 20 minutes was 501.
/hr. In the latter half of the reaction, the concentration of chromium chloride in the bath increased, and the catalytic action of chromium chloride became stronger.

The produced chromium chloride remained dissolved in the molten salt bath as a divalent and trivalent mixture. Note that when chromium chloride was not added first, it took 4 to 5 hours for the chlorination rate to reach 40 g/hr.

Example 3 CrC412, 100 parts by weight of the same mixed salt as in Example 2,
Using a molten salt bath containing 5 parts by weight of 77019C
6 to 10 mm at 1Cj12 gas flow rate of 300m1/min
As a result of chlorinating the granular N1 using the apparatus shown in Figure 2, the Ni chlorination rate was 15.3 (1/hr).

Comparative Example 2 CrC. As a result of chlorinating Ni under the same conditions as in Example 3 without adding Ni, the chlorination rate was 1.55 g/hr.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing one embodiment of the present invention. In Figure 1, 1 is the gas inlet, 2 is the reaction tube, 3 is the electric furnace, and 4
is a molten salt bath, 5 is a cooler, 6 is a product, 1 is an exhaust gas outlet, 1 is a gas inlet in Figure 2, 2 is a reaction tube, 3 is an electric furnace, 4
5 indicates a molten salt bath, 5 indicates a raw material, and 6 indicates an exhaust gas outlet. Patent Applicant: Toyo Soda Kogyo Co., Ltd. Figure 1 Figure 2 Procedural Amendment Commissioner of the Patent Office Gakudono Shiga July 23, 1981 1. Indication of the case 1989 Patent Application No. 108295 2. Name of the invention Molten salt bath Chloride Law 3 Relationship with the person making the amendment Patent applicant address 4560-4 Oaza Tomita, Shinnanyo City, Yamaro Prefecture 746
Number of inventions increased by amendment 5, date of amendment order voluntary amendment 6 Specification subject to amendment Column 1 for detailed explanation of invention Contents of amendment "Nahare" was corrected to "Naware". 3) Specification page 4 line 9 r HacJ J was corrected to "11ac O". 4) Specification page 6, line 8 r = '5:38 Near J was corrected to [=55.3B Near J. that's all

Claims (1)

[Claims] 1) In a method of chlorinating a metal component such as a metal or a metal-containing substance in a molten salt bath, a metal capable of forming a higher chloride capable of chlorinating the metal component, or a chloride thereof, is used. Molten salt bath chlorination method characterized by adding to the molten salt bath 2) Fe, Cr, Nb, Ta1Sn, V, Cu
Alternatively, the method according to claim 1, in which chlorination is carried out by adding one or more of these chlorides to a molten salt bath.