JP2000001318A - Calcination furnace for iron chloride aqueous solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calcination furnace for iron chloride aq. solution capable of stabilizing the quality of iron oxide with improved control of the deviation of a swirling flow in the furnace compared to the conventional. SOLUTION: The calcination furnace for iron chloride aq. solution is provided with a blow port 3 for heat source gas, which is arranged on the furnace wall the cylindrical furnace body for forming a swirling flow of the heat source gas in the furnace, and a spray port 6 for spraying the iron chloride aq. solution generating hydrochloric acid, which is brought into contact with the heating source gas to generate iron oxide and hydrogen chloride. In such a case, plural gas discharge ports 11 for introducing a gas containing hydrogen chloride to the outside of the furnace are separately provided at an equal interval along the circumference in the upper part of the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roasting furnace for an aqueous solution of iron chloride, and more particularly, to a roasting furnace for producing iron oxide and hydrogen chloride by spraying an aqueous solution of iron chloride into a swirling flow of a heat source gas. About the furnace.

[0002]

2. Description of the Related Art Generally, a roasting process as shown in FIG. 8 is used to heat an aqueous solution of iron chloride to cause a chemical reaction to recover hydrogen chloride and produce iron oxide. The main device in this step is the roasting furnace 1, which uses a flame and / or a heated gas (hereinafter, referred to as a heat source gas) as a heat source and uses them as a heat source gas inlet 3 of a blowing device 2.
, So as to form a swirling flow 5 in the furnace. The aqueous solution of iron chloride 7 of the material to be heated is
It is sprayed into the furnace through the spray port 6, which is heat-exchanged in advance with the gas 10 containing hydrogen chloride in the roasting furnace 1 in the absorption tower 8 to concentrate the iron chloride before spraying. . The gas 10 containing hydrogen chloride is discharged from the gas discharge port 11 of the roasting furnace 1, and most of the iron oxide entrained in the gas 10 is recovered by the cyclone 9 before being introduced into the absorption tower 8. It is supposed to be. The hydrogen chloride that has exited the absorption tower is adhered to water or the like, and is used as a hydrogen chloride aqueous solution or the like.

[0003] In the roasting furnace 1, the sprayed iron chloride aqueous solution 7 is heated, and solid iron oxide 17 (F ₂ O ₃ ) and gaseous hydrogen chloride (HCl) 1 are heated according to the following reaction formula.
8 is generated. 2FeCl ₂ + (1/2) O ₂ + 2H ₂ O → Fe ₂ O ₃
+ 4HCl 2FeCl ₂ + 3H ₂ O → Fe ₂ O ₃ + 6HCl At this time, the aqueous iron chloride solution 7 is sprayed from the spray port 6 in an umbrella-like (radial) manner, so that the generated iron oxide 17 is, as shown in FIG. Most of them fall along the inner wall 20 of the roasting furnace 1.

On the other hand, in such a roasting furnace 1, FIG.
As shown in FIG. 3, the heat source gas injection port 3 has a shaft whose center is the furnace center 1 so that the heat source gas is swirled along the inner wall 20.
It is attached so that it faces in the direction that does not intersect with 4.
The angle 19 formed by the center axis of the blowing port with the tangent line 16 of the inner wall 20 varies depending on the size of the roasting furnace 1,
It is in the range of 30 °. The quality of the iron oxide depends on the operating conditions of the roasting furnace 1, namely, the spraying state, the raw material throughput, the furnace temperature,
It is affected by the velocity of the swirling flow. Quality control techniques for operating these influential factors are disclosed in JP-A-61-86425, JP-A-4-270127, and JP-A-6-487.
No. 40, JP-A-7-41320 and the like. However, these quality control techniques are based on iron oxide 1
7 rather than deliberately controlling the quality of
This is merely a quality control operation corresponding to the change of the iron oxide quality due to the change of the situation described above, and does not focus on the formation of the turning condition that can stabilize the iron oxide quality.

[0005]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention can suppress the bias of the swirling flow in the furnace, make the temperature distribution uniform, and stabilize the quality of iron oxide. It is an object of the present invention to provide a roasting furnace for an aqueous iron chloride solution. If the swirling flow is separated and the temperature distribution becomes non-uniform, the contact efficiency between the swirling flow and the aqueous solution of iron chloride deteriorates, and the reaction tends to be insufficient. As a result, the quality of the iron oxide varies.

[0006]

Means for Solving the Problems In order to achieve the above object, the inventor has diligently made efforts to develop means for suppressing the bias of the swirling flow in the furnace and making the temperature distribution uniform, and completed the present invention. did. That is, the present invention provides a heat source gas inlet provided on a furnace wall of a cylindrical furnace body for forming a swirling flow of the heat source gas in the furnace, and generates iron oxide and hydrogen chloride by contacting the heat source gas. In an iron chloride aqueous solution roasting furnace equipped with a spray port for spraying an iron chloride aqueous solution to be sprayed, gas outlets for guiding the gas containing hydrogen chloride to the outside of the furnace are arranged at equal intervals along the circumference of the furnace body upper part. A roasting furnace for an aqueous solution of iron chloride, wherein a plurality of roasting furnaces are provided apart from each other. According to the present invention, since the gas containing hydrogen chloride is appropriately extracted from the upper part of the furnace body, the bias of the swirling flow in the furnace can be suppressed as compared with the related art. As a result, the quality of the manufactured iron oxide was more stable than before.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below, including the circumstances leading to the invention. First, the inventor repeated research on the swirling flow 5 of the heat source gas in the roasting furnace 1. Then, it was concluded that the cause of the deviation of the center axis 12 of the swirling flow 5 to cause the deviation was as follows. That is, (1) the heat source gas inlets 3 are not evenly arranged in the circumferential direction of the furnace body, and (2) the iron oxide 1 provided on the furnace bottom.
The outlet 13 of 7 is not arranged at the center 14 of the circumference of the furnace body. (3) The gas outlets 11 in the upper part of the furnace body are not uniformly arranged in the circumferential direction. This is the central axis 1 of the swirling flow 5
2 suggests that it is desirable to overlap the furnace center 14 as shown in FIG. However, in the conventional roasting furnace 1 for the iron chloride aqueous solution 7, although the above (1) and (2) are considered, there is no one considering (3).

The inventor of the present invention has made intensive studies on the arrangement of the gas outlets 11 in the upper part of the furnace body, and has completed the present invention described below. As shown in FIGS. 1 and 2 below, a plurality of gas outlets 11 are provided at equal intervals along the circumference of the upper part of the furnace body to smoothly discharge the swirling flow 5 without disturbing the flow. I did it.

A roasting furnace 1 according to the present invention is a cylindrical body,
The body from the upper part to the middle part of the furnace is a cylinder, and a cone-shaped cylinder is connected below the body. Further, a gas outlet 11 for discharging a gas containing hydrogen chloride generated in the furnace is provided at an upper portion of the furnace body. A spray port 6 for spraying an aqueous solution of iron chloride 7 as a raw material is provided. The spraying of the aqueous solution of iron chloride is preferably performed using a spray or the like, and the spray port is preferably a spray nozzle. Further, a blowing device 2 for a flame serving as a heat source and / or a heated gas (heat source gas) is attached to a wall of the body. The blowing device 2 directly burns a combustion exhaust gas obtained by burning a mixture 4 of a fuel gas (for example, coke oven gas) and a gas (for example, air) together with a flame from the heat source gas injection port 3 into the furnace. It is something that can be blown. At this time, heated air (hot air) is also blown into the roasting furnace 1 together with the flame. In order to form the swirling flow 5 of the heat source gas in the roasting furnace 1, the direction in which the flame and the heated gas are blown is such that the central axis of the heat source gas blowing port is the furnace in plan view. 8 to 3 for the tangent to the body wall
The angle is set to 0 °. In side view,
It is preferable to be horizontal, that is, not to be tilted up and down. In the present invention, the number of the blowing ports 3 may be one or more. However, it is preferable that a plurality of the blowing ports 3 are provided, and the blowing ports 3 are uniformly arranged on the body of the roasting furnace 1 along the circumference. Further, a valve for discharging generated iron oxide 17 may be provided at the lower end of the cone body below the body.

Next, a feature of the present invention is that the roasting furnace 1 described above is used.
A plurality of gas outlets 11 are provided at equal intervals along the circumference of the upper part of the furnace body, as illustrated in FIGS.
The reason is that the swirling flow 5 is smoothly discharged without disturbing the flow. As a result, the gas containing hydrogen chloride uniformly escapes from the gas discharge port 11, and the swirling flow 5 in the furnace becomes even and the quality of the iron oxide 17 to be manufactured can be stabilized. The position where the gas discharge port is installed is preferably higher than the spray port 6. This is to prevent discharge of the aqueous solution of iron chloride as the material to be heated.

The gas 10 contains hydrochloric acid 18 and water vapor generated in the furnace, the blown heat source gas and the iron oxide 1
7 and the like. Further, the roasting furnace 1 according to the present invention does not limit the type of the iron chloride aqueous solution 7, which is a raw material to be roasted, and can be applied to any aqueous solution containing iron chloride. However, use of waste hydrochloric acid generated in steel pickling equipment such as smelting equipment in a cold rolling process of an ironworks is preferred. The reason is that it can be obtained at low cost.
Further, the concentration of iron chloride in the aqueous iron chloride solution 7 is preferably 10 g / liter or more as Fe concentration, more preferably 10 to 500 g / liter, but is not particularly limited. In addition, the iron chloride aqueous solution 7 may contain a compound composed of Zn, Mn, Mg, Si, Cr, Al, or the like.

[0012]

(Embodiment 1) As shown in FIG. 1, a roasting furnace 1 according to the present invention is used in which two gas outlets 11 are installed at equal intervals (180 ° from each other) at the upper part of a furnace body. Thus, iron oxide was produced from the aqueous iron chloride solution 7. In addition, the heat source gas blowing ports were installed at two locations at equal intervals. The operating conditions of the roasting furnace 1 are as follows: spray amount of the aqueous solution of iron chloride 7: 3.5 m ³ / hour, iron concentration in the aqueous solution of iron chloride: 22 g / 100 ml, hot air volume blown: 5500 Nm ³ / hour, hot air temperature : 1400 ° C
It is. The average particle size of the obtained iron oxide particles and the chlorine content in the iron oxide were measured every hour after the start of production, and the results are shown in FIGS. 5 and 6. The maximum value of the average particle size is 0.8
0 μm, the minimum value was 0.75 μm, the maximum value of the chlorine content was 0.14 wt%, and the minimum value was 0.10 wt%. Further, the temperatures at four locations shown in FIG. 1 were measured, and the average value of each was determined. The temperature reading is 1 m above the heat source inlet and 30 cm from the inner wall of the furnace. The average value of the temperature at the measurement point a is 694 ° C., and the average value of the temperature at the measurement point b is 70.
The temperature at measurement point c was 2688C, the measurement point was 688C, and the average temperature at measurement point d was 696C. The average particle size is
It was measured by the air permeation method.

(Embodiment 2) As shown in FIG. 2, a roasting furnace 1 according to the present invention in which four gas discharge ports 11 are installed at equal intervals (90 °) in the upper part of a furnace body, Iron solution 7
To produce iron oxide 17. In addition, the heat source gas blowing ports were installed at two places at equal intervals. The operating conditions of the roasting furnace are:
This is the same as the first embodiment. The changes over time in the average particle size of the obtained iron oxide particles and the chlorine content in the iron oxide were measured in the same manner as in Example 1. The results are shown in FIGS. The maximum value of the average particle diameter is 0.78 μm and the minimum value is 0.75 μm.
μm, and the maximum value of the chlorine content was 0.11 wt% and the minimum value was 0.09 wt%. Further, the temperatures at four locations shown in FIG. 1 were measured, and the average value of each was determined. The temperature measurement position is 1 m above the heat source inlet and 30 m from the inner wall of the furnace.
cm place. The average value of the temperature at the measurement point a was 690 ° C., the average value of the temperature at the measurement point b was 690 ° C., and the average value of the temperature at the measurement point c was 699 ° C.

Comparative Example 1 As shown in FIG. 3, an iron oxide 17 was produced from an aqueous solution of iron chloride 7 using a conventional roasting furnace 1 having one gas outlet 11 at the upper part of the furnace body. In addition,
The heat source gas injection ports were installed at two places at equal intervals. The operating conditions of the roasting furnace 1 are the same as in the first embodiment. The time-dependent changes in the average particle size of the obtained iron oxide particles and the chlorine content in the iron oxide were measured in the same manner as in Example 1. Fig. 5 shows the results.
And FIG. The maximum value of the average particle size is 0.85μ
m, the minimum value was 0.73 μm, the maximum value of the chlorine content was 0.23 wt%, and the minimum value was 0.10 wt%.
Further, the temperatures at four locations shown in FIG. 1 were measured, and the average value of each was determined. The temperature measurement position is 1 above the heat source inlet.
m, 30 cm from the inner wall of the furnace. The average temperature at the measurement point a is 691 ° C., and the average temperature at the measurement point b is 675.
° C, the temperature at the measurement point c was 682 ° C, and the average temperature at the measurement point d was 702 ° C.

(Comparative Example 2) As shown in FIG. 4, a roasting furnace 1 provided with two gas discharge ports 11 in the upper part of the furnace body was used.
Iron oxide 17 was produced from the aqueous iron chloride solution 7. In addition, the heat source gas blowing ports were installed at two locations at equal intervals. The roasting furnace 1
Are the same as in the first embodiment. The changes over time in the average particle size of the obtained iron oxide particles and the chlorine content in the iron oxide were measured in the same manner as in Example 1. The results are shown in FIGS. The maximum value of the average particle diameter is 0.80 μm, the minimum value is 0.72 μm, and the maximum value of the chlorine content is 0.20 μm.
wt%, and the minimum value was 0.11 wt%. FIG.
The temperatures at the four locations shown in Table 2 were measured, and the average value of each was determined. The temperature measurement position was 1 m above the heat source inlet and 30 cm from the inner wall of the furnace. The temperature average value of the measurement point a is 6
80 ° C., average value of temperature at measurement point b is 678 ° C., measurement point c
Was 700 ° C., and the average value of the temperature at measurement point d was 703 ° C.

[0016]

As described above, according to the present invention, in a roasting furnace for an aqueous solution of iron chloride, the heat source gas turns evenly, the temperature distribution becomes more uniform, and the average particle size of the manufactured iron oxide is reduced. In addition to being uniform, quality characteristics such as chlorine content have become more stable.

[Brief description of the drawings]

FIG. 1 is a diagram showing a roasting furnace for an aqueous solution of iron chloride according to the present invention, wherein (a) is a plane surface and (b) is a side surface.

FIG. 2 is a view showing another embodiment of the roasting furnace for an aqueous solution of iron chloride according to the present invention, wherein (a) is a plane and (b) is a side.

FIG. 3 is a view showing a conventional iron chloride aqueous solution roasting furnace;
(A) is a plane, (b) is a side surface.

FIG. 4 is a view showing another embodiment of a roasting furnace for an aqueous solution of iron chloride other than the example of the present invention, wherein (a) is a plane and (b) is a side.

FIG. 5 is a diagram showing the change over time in the average particle size of the iron oxides produced in Examples 1 and 2 and Comparative Examples 1 and 2.

FIG. 6 is a graph showing the change over time in the amount of chlorine contained in the iron oxides produced in Examples 1 and 2 and Comparative Examples 1 and 2.

FIG. 7 is a plan view showing a swirling flow of a heat source gas, and FIG.
Indicates a non-biased swirling flow, and (b) indicates a non-uniform swirling flow.

FIG. 8 is a diagram showing a process for producing iron oxide from an aqueous solution of iron chloride.

FIG. 9 is a diagram illustrating a falling state of iron oxide.

FIG. 10 is a plan view of the inside of a furnace for explaining blowing of a heat source gas.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 roasting furnace 2 heat source gas blowing device 3 heat source gas blowing port 4 mixture of heating gas and gas 5 swirling flow 6 spray port 7 iron chloride aqueous solution 8 absorption tower 9 cyclone 10 gas containing hydrogen chloride 11 gas Outlet 12 Center axis of swirling flow 13 Outlet of iron oxide 14 Furnace center 15 Center axis of inlet 16 Tangent line of inner wall 17 Iron oxide 18 Hydrogen chloride (hydrochloric acid) 19 Tangent line of center axis of inlet and inner wall Angle 20 Inner wall 21a, 21b, 21c, 21d Temperature measurement point

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toru Takeuchi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba F-term (reference) 4K002 AA03 AB02 AD04

Claims (1)

[Claims] 1. An inlet for a heat source gas provided on a furnace wall of a cylindrical furnace body for forming a swirling flow of the heat source gas in the furnace, and contacting the heat source gas to generate iron oxide and hydrogen chloride. In a roasting furnace for an aqueous solution of iron chloride provided with a spray port for spraying an aqueous solution of iron chloride, a gas outlet for guiding the gas containing hydrogen chloride to the outside of the furnace is provided at regular intervals along the circumference of the upper part of the furnace body. A roasting furnace for an aqueous solution of iron chloride, wherein a plurality of furnaces are provided separately.