JPS6012976B2 - Method for producing chromium dichloride and iron dichloride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simultaneously producing chromium dichloride and iron dichloride from ferrochrome or chromium-iron reduced pellets and chlorine.

Chromium dichloride is used for the production of chromium trichloride, metallic chromium, and chromizing, and iron dichloride is used for dyes, soot beams, metallurgy, preparations, and magnetic iron oxide as a raw material for ferric chloride.

The following method has been announced for producing chromium dichloride and iron dichloride using ferrochrome.

For example, the process of US Pat. No. 1,814,393 involves reacting a chlorine gas stream with ferrochrome in the presence of molten salts of chromium dichloride and iron dichloride to produce a mixture of chromium dichloride and iron dichloride. Also, A. Itetelekov and others of the Soviet Union are Tr. UralNaMh-lssled. Khi
m. 1Ship Volume 16, pp. 116-122 (1967)
84,000 to 10 ferrochrome and seawater hydrogen chloride to
He has announced a method for obtaining chromium dichloride and iron dichloride through a reaction at 00°C. Furthermore, the method described in Soviet Union Inventor's Certificate No. 170 uses a vertical chlorination apparatus to chlorinate ferrochrome with gaseous chlorine in the range of 95 and 0 to 100 p0 to produce chromium dichloride and iron dichloride. This is an improved manufacturing method.

Furthermore, El Debyatovskaya of the Soviet Union and others are Tr. U
Target 1. NaMh. lssled. Khim. 1 ship t1
Vol. 6, No. 89-102 (1967) describes a reaction system for a method for producing chromium dichloride and iron dichloride from ferrocomb and chlorine by Jia Bilnyansky.

However, the known methods involve many problems that still need to be solved for industrialization.

In other words, the reaction heat during the chlorination reaction is extremely high, and 9
It is a high temperature reaction of 50 to 1000°C.

Additionally, L. Debyatovskaya et al. state that there is always a risk of corrosion and destruction of the equipment material due to localized overheating. Furthermore, ferrochromes generally contain several percent carbon, which does not react with chlorine even at 950 oo to 1000 qC, making it difficult to remove or extract it in methods that require the use of high-temperature reactors. .

The present inventors completed the present invention as a result of various tests and studies in order to solve the problems in the method of producing chromium dichloride and iron dichloride from ferrochrome and chlorine.

That is, in the present invention, a vertical packed column is filled with chromium/iron-reduced pellets or ferrochrome, and the packing body is maintained at 670 CO or more and less than 95,000 CO, and chlorine gas is introduced into the packing body together with an inert gas. At the same time, an inert gas is introduced into the tower from below the chlorine gas introduction part, and the reaction product iron dichloride is used as a gaseous body accompanied by the inert gas, and chromium dichloride is melted. This is a method for producing chromium dichloride and iron dichloride, which is characterized in that they are obtained separately.

The introduction part of chlorine gas can be selected from the central zone of the packing body or the high layer zone, but the produced iron dichloride gas is from the high layer zone in the former case, and from the central zone in the latter case. be discharged.

Since chromium dichloride is discharged as a melt, it is discharged from the bottom of the column in any case. Ferrochrome is iron oxide,
It is produced by reducing chromium ore, which contains chromium oxide as a main component and further contains oxides such as aluminum, magnesium, and silicon.

Further, chromium-iron reduced pellets are obtained by granulating a mixture of chromium ore powder and carbon powder and partially reducing the pellet in a solid phase, and are usually used as an intermediate raw material in the production of fluorochrome. The former includes high carbon ferrochrome and low carbon ferrochrome, but generally the molar ratio of chromium to iron is 1.9 to 3.5, and the latter includes iron, unreduced chromium oxide, and slag components. etc. are included. First, the knowledge obtained by the present inventors in completing the present invention will be explained. ○ー It is known that the chlorination rate of ferrochromes is faster at high temperatures. Furthermore, as mentioned above, the reaction temperature range was considered to be 95,000 to 100 mm. The present inventors have conducted various tests and studies and found that the first point at which the chlorination rate of ferrochromes rapidly increases is the eutectic temperature of chromium dichloride and iron dichloride670
It was determined that the value was around qo. Furthermore, the following experiment was conducted to examine the relationship between the chlorination reaction rate of fluorochrome and temperature above the above-mentioned temperature. Experimental example Chlorine 1% by volume, argon 9% from below a vertical packed bed of ferrochrome (37.2% by weight of iron, chrome spheres, 8% by weight, 8% by weight of carbon, 0.% by weight of silicon) Each of the vertical packed beds was maintained at a required temperature by passing a mixed gas of % by volume, and after condensing and separating chloride from the exhaust gas from the top of the packed bed, the gas was circulated.

A manometer differential pressure gauge was installed in the exhaust gas line, and the pressure drop accompanying the reaction of chlorine gas was measured to determine the chlorination rate. The results are shown in FIG. In the figure, the vertical axis is the reading of the manometer differential pressure gauge in units of skin, and the mechanical axis is time in minutes.

Curves 1, 2, 3, 4, and 5 in the figure are the temperatures of the packed bed, respectively.
Shows 00000. The experimental examples show that there is little difference in the chlorination temperature of ferrochrome in the range of 70,000 to 100,000, and that the conventionally known temperature of 950q0 to 100,000 is not necessary.

Legs The inventor further found that chromium 53 with an average particle size of 0.8 skin
．． A quartz tube with a diameter of 25 mm and a height of 170 mm was filled with high carbon ferrochrome grains containing 37.2 percent by weight of iron and 37.2 percent by weight of iron. The temperature was set to 670 to 850 (○).

In this case, in this temperature range, if the residence time of the mixed gas at the superficial velocity in the packed bed is at least 1 second, the only gas that is discharged is the mixed gas of iron dichloride and nitrogen, and the intermediate product is None of the expected iron trichloride or chromium trichloride, or free chlorine, was emitted. '3} The vapor pressure of iron dichloride is chloride dichloride.

It is known that the vapor pressure is extremely high compared to the vapor pressure of the vapor.
Temperature ℃ 750 800 850 900 950
1,000PFeCIZ/2,27o 139 7
5 66 45 33.8PCrC12PFec
12 and Pcrc12 indicate the vapor pressure of iron dichloride and chromium dichloride, respectively.

It is also known that total pressure measurements approximately follow Raoult's law.

'4} The chlorination reaction of ferrochrome is an exothermic reaction, but as mentioned above, the reaction temperature may be at least 97 mm.

In order to prevent local heating due to reaction heat and excessive temperature rise due to reaction heat, inert gas may be introduced into the reaction zone.

The ratio of inert gas and chlorine for this purpose can be determined as follows, for example.

Chrome 53. Round weight%, iron 37. When ferrochrome containing % of public electricity is chlorinated, iron dichloride is discharged as a gas and chromium dichloride is discharged as a liquid, and when other heat balances are ignored, the dilution rate of chlorine gas with inert gas (nitrogen) is It will look like this:

Reaction temperature 700°C 800°C Heat of formation Kcale/Ferrochrome 966.4 9
23.7 Chlorine/Nitrogen + Chlorine Younger brother 7.9 9.5
In other words, it can be seen that the temperature control described above can be achieved by diluting with an inert gas at room temperature during chlorination with chlorine gas.

■ It has been found that even after chlorination, ferrochrome grains generate iron dichloride and chromium dichloride, their shape does not change and they maintain considerable hardness due to the presence of unreacted ferrochrome and carbon. Ta.

{6) It was found that after the chlorination reaction, unreacted carbon maintained approximately the same shape as the raw material ferrochrome, and it was found that it could be flowed out from the reaction zone together with the chromium dichloride melt.

The matters that formed the basis for the inventor to complete the present invention have been described above.

According to '11, Dilution of chlorine maintains the reaction at low temperature and prevents corrosion and destruction of equipment due to local heating.
} Therefore, ferrochrome is excellent as a packed bed forming material, and the present invention can also be carried out by a continuous method.

Although all of the above has been explained using ferrochrome as an example, the same applies to reduced pellets as well.

Next, the present invention will be explained based on FIGS. 2 and 3 showing specific embodiments.

First, FIG. 2 will be explained.

6 is a vertical packed column, 7 is a ferrochrome and chromium iron reduction pellet inlet provided at the top of the column, 8 is a molten product discharge pipe provided at the bottom of the column, and 9 is provided in a central zone within the column. 10 is an inert gas inlet provided below 9, and 11 is a produced iron dichloride gas outlet.

First, ferrochrome or chromium iron reduced pellets are charged into the column from the input port 7.

The tower can be divided into a central zone 12 near the chlorine inlet 9, a high zone 13 above it, and a low zone 14 below. Mixing chlorine gas and an inert gas such as nitrogen into the tower or supplying them separately from the inlet 9, and maintaining the temperature of the reaction zone in the tower at 670 pm or more and less than 950 pm,
In addition, an inert gas is introduced from the inlet 10 in the lower part.

It is necessary to preheat this inert gas and maintain it at approximately 820 oC or more and less than 950 qo so as not to lower the temperature at the bottom of the packed bed. Chlorine gas reacts with ferrochrome or chromium iron reduced pellets to produce chromium dichloride, iron dichloride, chromium trichloride, and iron trichloride as the main reaction products.

The molten salt in the product flows down into the lower zone 14 of the packed bed, and the gas rises to the upper zone 13. The inert gas introduced from 10 and the flowing molten salt come into countercurrent contact at 14, the molten salt is piled up, and a portion of it rises to reach the central position zone 12 again.

In this process, trichloride is reduced to dichloride by fluorochrome or chromium iron reducing pellets. In order to prevent the molten chromium dichloride flowing down the tube 14 from solidifying, it is necessary to maintain the temperature particularly at the lower part at 820 oo or higher. Inert gas accompanied by reaction products rises from the central zone 12, and the reaction products include iron trichloride, chromium trichloride, iron dichloride, and chromium dichloride, as well as chlorine and the like. These rise up the high vertical body 13, and in the process the remaining trichloride becomes dichloride.

The vapor pressure difference between chromium dichloride and dichloride Q weight is large, and the gas is retained while rising through the packed bed of the higher layer body 13, and the gas discharged from the outlet 11 is substantially reduced. It is possible to use only iron dichloride accompanied by an inert gas. Further, unreacted fluorochrome or a molten chromium dichloride containing reduced pellets, slag, etc. is discharged from a discharge pipe 8 provided at the bottom of the column.

To separate chromium dichloride from this melt, for example, by melting it in water, only the chromium dichloride will dissolve, so it can be easily separated. The amount of chlorine added should not be greater than the amount necessary for the iron chromium in the ferrochrome or chromium iron reduced pellet to be converted to dichloride.

If the amount is too high, trichloride and unreacted chlorine will be discharged outside the tower. FIG. 3 shows another embodiment of the method of the invention.

The vertical packed tower 6, the ferrochrome and iron chromium reduction pellet inlet 7, the molten product discharge pipe 8, and the inert gas introduction pipe 10' provided below are exactly the same as those shown in FIG. The difference in Fig. 2 is that the chlorine gas and inert gas inlet 9 is connected to the upper layer zone 13 of the tower, and the produced iron dichloride gas discharge
1 is present in the central position zone 12 of the tower. First, ferrochrome or reduced pellets are introduced and filled into the column 6 through the inlet 7.

Chlorine gas and an inert gas such as nitrogen are mixed and separately introduced into the column through a plurality of inlets 9. The high layer zone 13 near the inlet for the chlorine gas and inert gas is a reaction zone where a chlorination reaction occurs. This reaction zone maintains a temperature of 670 qo or more and less than 950°C. The main products of the chlorination reaction are chromium dichloride, iron dichloride, chromium trichloride, and iron trichloride. The product consists of gas and molten salt and descends from the upper pupil zone 13 to the central zone 12. Further, an inert gas such as nitrogen is introduced from the introduction pipe 10 in the lower part. The central position zone 12 is 67, similar to the high calendar zone 13.
Keep the temperature above 0℃ and below 950℃. The trichloride in the product becomes dichloride by the action of the fluorochrome or iron chromium reduction pellet, and these molten salts flow down to the lower part 14. The gas in the product is discharged from the outlet 11 in the central zone along with the inert gas.

The gas discharged together with this inert gas is substantially mostly iron dichloride due to its vapor pressure. The molten salt further flows down to the lower ephemeris zone 14.

The temperature of the low-position body is also maintained at 670° C. or more and less than 950° C., and an inert gas is introduced from below. The molten salt and the inert gas collide in countercurrent flow, and the iron dichloride in the molten salt is vaporized and rises along with the inert gas, and is finally discharged from the outlet 11 in the central zone. While descending from 14, the molten salt comes to consist essentially of chromium dichloride and coexists with unreacted ferrochrome, slag, and the like.

Therefore, the temperature in the vicinity of the discharge port 8 from the lower part of the lower layer zone must be set to a melting temperature of about 820° C. or higher to prevent chromium dichloride from solidifying. Separation of chromium dichloride can be easily carried out as already mentioned above. Further, separation of iron dichloride accompanied by inert gas is easily performed by cooling or the like.

The present invention has been described above using two typical examples.

The method of the invention can be carried out either continuously or intermittently. In the intermittent method, ferrochrome, ku. When the chlorination of the chromium iron-reduced pellets progresses and the chlorination rate decreases, all the filler is discharged from the lower discharge port 8, and then new ferrochrome or chromium-iron reduction pellets are introduced. In addition, when carrying out continuously, introduce ferrocomb or chromium iron reduction pellets at a constant flow rate from the input port 7,
A melt containing the product chromium dichloride is continuously discharged from the bottom.

In any case, the packing body does not change its shape even after chlorination,
In addition, by making the lower part mixed with the melt, the filling can be smoothly moved and discharged.

The following will be explained based on examples.

Example 1 A quartz tube having the structure shown in FIG. 2 was provided in a vertical electric furnace, and ferrochrome was chlorinated to produce iron dichloride and chromium dichloride.

The quartz tube has an inner diameter of 12 cm, a total height of the upper zone and the middle zone of 80 arcs, and a height of the lower layer body of 40 arcs.

Raw materials: chromium 53.3% by weight, iron 37.2% by weight
, carbon 8. Box weight%, silicon 0. A high carbon ferrochrome with an average grain size of about 1.5 mm was used.

At the start of operation, a bag of molten salt, which is chromium dichloride or a mixture of sodium chloride, potassium chloride and magnesium chloride, is placed in a bag along with high carbon ferrochrome at the bottom of the column.
Although it is heated and maintained in a molten state, pure nitrogen is introduced in advance through the lower inert gas introduction pipe 10 and the introduction port 9 of the central position body, and is discharged from the discharge port 11 to sufficiently replace the inside of the column with nitrogen. <There is a need.

The inside of the tower above the upper half of the low-position body 14 is heated to 700°C for 1
The lower half of the 4 was maintained at 82 pi 0. Furochrome with the above composition is fed through the inlet 7 at a rate of 432.1 m/hr, and chlorine at room temperature with a chlorine concentration of 6.5% is fed through the gas inlet 9.
Nitrogen mixed gas: 140.7 liters of chlorine and 19 liters of nitrogen per hour
At a rate of 95.35 liters, inert gas introduction pipe 1
Nitrogen gas preheated to 820°C is pumped at 1906°C per hour.
When the mixture was continuously introduced into the quartz tube at a rate of 0 liters (N.T.P.), the mixed gas was continuously discharged from the discharge row 1 and the molten material was continuously discharged from the discharge port 8. The gas mixture consisted of iron dichloride, chromium dichloride, and nitrogen, and the emissions were 3137 liters per hour, 0.61 liters per hour, and 3901.3 liters per hour (N.T.P.), respectively.

The discharged mixed gas is cooled to approximately 500°C to precipitate and separate iron dichloride and chromium dichloride, and the remaining gas is filtered through a furnace made of quartz cloth to further remove solids and obtain a gas consisting mostly of nitrogen. Ta.
Nitrogen gas was recycled. The melt is chromium dichloride,
It consisted of carbon and unreacted fluorochrome.

When this melt is cooled and eluted with water, only chromium dichloride is eluted. The eluted chromium dichloride solution contained almost no other substances, and pure chromium dichloride was obtained. Based on the amount of obtained products, the amount of chromium dichloride, carbon and reacted ferrochrome discharged as melts was calculated to be 426.1, 30.8 and 371.6 hours per hour.
The residence time of the mixed gas passing through the central zone and the high layer zone is at the above temperature and superficial velocity of 2. Kyoaki, linear velocity signature. 2 skin/s
It was ec. The reaction rate of high carbon ferrochrome after one pass was 86%.

Example 2 Iron dichloride and chromium dichloride were produced by chlorinating chromium and iron-reduced pellets in a high alumina reaction tube shown in FIG. 3 installed in a vertical electric furnace.

The inner diameter of the reaction tube is 1, the height of the middle position zone 12 and the high level counterfeit zone 13 is 12 lus in total, and the height of the low level zone 14 is 130 mm.

The raw materials are chromium, iron, silicon, magnesium, carbon, alumina, and calcium oxide, each at a weight percent of 37
．． 5, 12.1, 4.96, 6.39, 5.0, 9.8
, 1.1, and a particle size of 1 to 3 was used.

At the start of operation, bagging of the molten salt at the bottom of the tower and purging the inside with nitrogen were carried out in accordance with Example 1.

Next, the temperature of the upper half of the lower zone 12 in the reaction tube and the inside of the tube above it was kept at 700° C., and the lower half of the lower zone was heated to 82 psi.

The reaction was carried out as follows.

From input port 7, chrome iron moat pellets of the above composition are added per hour.
At 300 pm, the chlorine:nitrogen volume ratio was 6.1 from gas inlet 9.
:100 chlorine and nitrogen mixed gas at room temperature to 7 chlorine per hour
On the 163rd evening, 3453.4 liters of nitrogen and further nitrogen gas preheated to 82 liters were flowed into the reaction tube from the inert gas introduction pipe 10 at a rate of 917.1 liters per hour (N.T.P.). However, the mixed gas was continuously discharged from the discharge port 11 and the molten material was continuously discharged from the discharge port 8.

The mixed gas contains iron dichloride, chromium dichloride, silicon tetrachloride,
Consisting of magnesium chloride and nitrogen, the emissions are 178.6 pm, 0.5 pm, 195.1 pm, and 162 pm, respectively.
7 days and 4370.5 liters (N.T.P.).

This mixed gas was subjected to fractional cooling treatment to obtain pure iron dichloride. The melt was passed through a hot ceramic filter to separate pure chromium dichloride.

The amount of emissions of each composition of emissions including molten material is 575.8 nights per hour of chromium dichloride, 32.5 hours of carbon, 637 hours of alumina, 7.2 hours of calcium oxide, and approximately 650 hours of unreacted iron chromium reduced pellets. Met. The residence time of the mixed gas passing through the central zone and the upper layer zone was a superficial velocity of 6.2 seconds and a linear velocity of 19.4 k/sec at the above temperature.

In addition, the chromium iron reduced pellet was passed through the reaction tube, so that Hantoyo was chlorinated.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between ferrochrome chlorination reaction rate and temperature, FIG. 2 is a diagram showing one embodiment of the present invention,
FIG. 3 is a diagram showing another embodiment of the present invention. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A vertical packed column is filled with chromium/iron reduced pellets or ferrochrome, and while the packing body is maintained at a temperature of 670°C or higher and lower than 950°C, chlorine gas is supplied to the packing body together with an inert gas. At the same time, an inert gas is introduced into the column from below the chlorine gas introduction part, and the reaction product iron dichloride is reacted with the inert gas. A method for producing chromium dichloride and iron dichloride, which comprises separately obtaining chromium chloride as a melt. 2. The method according to claim 1, wherein chlorine gas is introduced into the middle zone of the packing body together with an inert gas, and iron dichloride accompanying the inert gas is obtained from the high zone of the packing body. 3. The method according to claim 1, wherein chlorine gas is introduced into the high zone of the packing body together with an inert gas, and iron dichloride accompanying the inert gas is obtained from the central zone of the packing body.