JPS5848642A - Manufacture of unfired agglomerated ore - Google Patents

Abstract

PURPOSE:To manufacture efficiently and economically high-strength agglomerated ore in a short time without carrying out firing by pelletizing a powdered or granular iron source contg. an added hydraulic binder and by subjecting the raw pellets to hydration curing with blown satd. steam and carbonation curing. CONSTITUTION:Prescribed amounts of fine iron ore, hydraulic cement and other additive as starting materials are fed from storage bottles 1a, 1b, 1c, well mixed with a mill 2, and pelletized with a pelletizer 3 to obtain raw pellets having a prescribed grain size. The raw pellets are charged into a vertical type shaft furnace 4 for hydration curing from the top, successively dropped in the furnace, and taken out of the bottom. During this time, satd. steam is blown into the furnace 4 at the required temp. from one side wall to the other opposite side wall so that it meets at right angles to the raw pellets. The raw pellets taken out of the bottom after hydration curing are charged into a shaft furnace 5 for carbonation curing from the top, and gaseous CO2 is blown into the furnace 5 from one side wall to the other opposite side wall so that it meets at right angles to the pellets. The pellets are carbonated, and the desired agglomerated ore is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a non-calcined agglomerate by agglomerating a powdery granular iron source without calcination.

As a method of agglomerating and pelletizing a powdered iron source or powdered iron ore without firing, a method of pelletizing the raw material using a hydraulic binder is known. This method has the excellent effect of agglomerating a powdery iron source in a pollution-free and energy-saving manner, but on the other hand, agglomeration requires a long period of curing, resulting in poor production efficiency.

For example, according to the example of Japanese Patent Publication No. 51-25402,
The pellets, which are agglomerated using Portland cement as a binder, require about 10 days of curing before they reach a strength sufficient for use, and therefore require a large curing zone. In addition, when the strength is developed by leaving the cold pellets naturally, the pellets stick to each other during the hardening process of the cold pellets, which necessitates a crushing process, which greatly reduces productivity and workability. This is a drawback.

In order to solve the above-mentioned problems and develop strength in a short time from pellets agglomerated using a hydraulic binder, a method of applying high-pressure hot water treatment in an autoclave has been proposed, for example, in Japanese Patent Publication No. 47-
No. 29688 has been proposed. However, when using this method, the manufacturing process has to be done in a patch manner, resulting in poor workability and high costs.In addition, it requires high-pressure equipment, which requires a large amount of equipment. In addition, there are problems such as the need for special precautions against high pressure.

From the above-mentioned viewpoints, the present invention provides a method for producing non-calcined agglomerate ore, which produces high-strength agglomerate such as 4rets in a short time, efficiently, and economically without calcination. Something,
In a method for producing uncalcined agglomerate ore, in which a raw pellet obtained by granulating a powdery iron source to which a predetermined proportion of a hydraulic binder has been added is subjected to curing treatment to produce agglomerate ore, the raw pellet is Water curing treatment by blowing saturated steam into the pellets,
It is characterized in that it can be made into a high-strength agglomerate in a short period of time by performing carbonation curing treatment by blowing carbon dioxide-containing gas into it.

Next, the present invention will be explained with reference to examples and drawings.

Example 1 Portland cement/as a hydraulic binder for Samalco powder ore.
The raw material was prepared by blending 10% by weight of water and adding 7% by weight of water in the outer frame, and granulating the raw material using a 1 mφ disc-type cover sizer to prepare raw pellets with a diameter of 10 to 14 mm.

The green pellets were hydrated and cured in saturated steam at 65°C for 5 hours, kept in a humidified CO2-containing gas at 90°C for 4 hours, and then hydrated in a CO2-containing gas at 200°C for 1.
It was held for 5 hours to form a product pellet.

FIG. 1 shows its crushing strength. In FIG. 1, the circle mark indicates the crushing strength of the product takulet manufactured by the method of the present invention described above. In addition, the marks 1 and Δ in FIG.
After hydration and curing for 9 hours in saturated steam at 200°C,
．． The crushing strength of the product pellets dried for 5 hours, and the symbol △ in Comparative Example 2 is the crushing strength of the 4 pellets obtained by leaving them in the atmosphere for 10 days and curing them. From the drawings, it can be seen that the product pellets produced by the method of the present invention, which are subjected to the carbonation reaction after the water utilization reaction, can be treated for a short time and have excellent crushing strength.

Example 2 This is an example in which water curing treatment and carbonation curing treatment were simultaneously applied to the same 4 let as in Example 1.
After holding for 5 hours in a humid CO2-containing gas mixed with water vapor at 65°C, and then for 4 hours in a humid CO2-containing gas at 90°C, for 1.5 hours in a dry CO2 atmosphere. It was held and made into a product pellet.

gl"-2, its crushing strength (○ mark) is shown together with the crushing strength (△ mark and 1 mark) of the comparative example described in Example 1. From the drawing, it can be seen that the water conservation treatment and carbonation The product pellets that were treated simultaneously with the curing treatment had a slightly inferior crushing strength compared to the pellets that were subjected to the hydration curing treatment Ze5 of Example 1 and the carbonation curing treatment, but It can be seen that it has excellent crushing strength compared to the comparative example without.

Example 3 The same raw pellets as in Example 1 were heated with saturated steam at 65°C for 5 minutes.
After curing under water for an hour, the pellets were held in a humid CO2-containing gas at 90°C for 4 hours, and then held in a CO2-containing gas at 200°C for 1.5 hours to form a product pellet. The concentration of CO2 gas during this carbonation curing treatment was varied and the relationship with the crushing strength of the product was investigated.

Figure 3 shows that the crushing strength is 9 in saturated steam at 65°C.
Shown together with a comparative example (marked 1) which was hydrated for an hour and then dried at 200° C. for 1.5 hours. As is clear from the drawing, when the concentration of CO2 gas is 20%, the crushing strength is 20%.
Even if the concentration is increased from 0 to 0, the crushing strength remains almost unchanged. In addition, even when the concentration of CO2 gas was 3%, the crushing strength was higher than that of the comparative example in which carbonation curing treatment was not performed, indicating its effectiveness.

Example 4 The same raw pellets as in Example 1 were hydrated under the same conditions as in Example 3, and then subjected to carbonation curing treatment using combustion exhaust gas with a CO2 temperature of 12.5% to obtain 4 pellets of product. The x mark in FIG. 3 indicates its crushing strength, which is 187 Kz/p. Almost the same effect as in Example 3 was obtained, and C was used as a carbon dioxide gas source.
It has been found that it is possible to utilize factory flue gas containing O2.

Example 5 The same raw pellets as in Example 1 were watered under the same conditions as in Example 3, and then subjected to carbonation curing treatment (however, using gas with a CO2 concentration of 100% by weight), and the C during this carbonation and curing treatment was
The flow rate of O2 gas was changed and the relationship with the crushing strength of the product was investigated.

FIG. 4 shows the crushing strength. It was found that the higher the CO2 gas flow rate, the better the crushing strength of the product pellet, and that the gas flow rate is preferably 1 cm/see or higher. For this reason, the carbonation curing treatment must be carried out in a manner that allows the raw material to come into efficient contact with CO2 gas.

FIG. 5 shows an example of steps for carrying out the method of this invention. Raw iron ore powder, hydraulic binder cement, and other additives are stored in storage bins la and l.
A predetermined amount is cut out from b and lc, thoroughly mixed in a mill 2, and then granulated in an eletizer 3 to form raw pellets of a predetermined particle size.

Reference numeral 4 denotes a vertical water curing shaft furnace, in which green pellets are charged into the shaft furnace 4 from the top of the furnace, successively descend through the furnace, and are discharged from the bottom.

Saturated steam at a predetermined temperature is blown into the shaft furnace 4 from one side wall to the opposite side wall, perpendicular to the green pellets as shown by the arrow, and this saturated steam descends inside the furnace. The 4 raw fish that will be harvested will be water-cured.

Thus, the pellets that have undergone water curing are discharged from the bottom of the shaft furnace and transferred to the carbonation curing shaft furnace 5.
It is loaded from the top. The carbonation curing shaft furnace 5 is
It is a vertical furnace similar to the hydration curing shaft furnace, and CO2-containing gas is blown from one side wall to the opposite side wall, perpendicular to the pellets in the furnace as shown by the arrow, and this CO2
Due to the contained gas, the pellets descending in the furnace are subjected to carbonation and curing treatment.

The four pellets that have undergone the carbonation and curing treatment are thus discharged from the bottom of the shaft furnace 5 and transported to the stockyard 6 as product pellets.

FIG. 6 shows an example in which the water-curing shaft furnace and the carbonation treatment shaft furnace are performed in one shaft furnace 7, where the upper half 7A of the shaft furnace is the hydration curing section, and the lower half 7B is the carbonation treatment shaft furnace. It is a department.

Note that the direction in which the saturated steam and carbon dioxide-containing gas are blown into the shaft furnace is not limited to the direction perpendicular to the direction of movement of the four let in the furnace as shown in the figure, but may also be directed, for example, from the top of the furnace to the bottom of the furnace. Alternatively, the air may be blown in the same direction and parallel to the moving direction of the red.

FIG. 7 shows another example of the process for carrying out the method of this invention, in which a grating 8 is placed on the upper part of the grating 8 that moves endlessly.
A steam blowing furnace 9 that blows saturated steam into CO2
A CO2-containing gas blowing furnace 10 for blowing a CO2-containing gas is provided, and while the green pellets supplied onto the grate 8 are moved by the grate 8, they are blown from a steam blowing furnace 9 provided above, Irrigation curing is performed by saturated steam sucked from the lower part of the grate 8, and then carbonation curing is performed by the CO2-containing gas blown from the CO□-containing gas blowing furnace 10 and also sucked from the lower part of the grate 8. The pellets that have undergone carbonation and curing treatment are discharged from the end of the grate 8 and transported to the stockyard 6 as product pellets.

The example described above consists of the steps of applying water curing treatment to 4 raw lets and then carbonation curing treatment, but 1
It is also possible to simultaneously perform water curing treatment and carbonation curing treatment by blowing a mixed gas of saturated steam and CO□ gas into one furnace.

In the method of this invention, the ratio of the hydraulic binder such as cement added to the powdery granular iron source is 3 to 3.
A suitable amount of 15% by weight is added to this hydraulic binder, as well as slaked lime,
Quicklime, converter slag, etc. may be added. In addition, the temperature during water curing treatment is 30-Ion℃, the temperature during carbonation curing treatment is 60-250°C1, the temperature during simultaneous treatment of water curing and carbonation curing is 30-250℃, and A suitable holding temperature using dry CO2 gas is 100 to 250°C.

In addition, the concentration of CO2 gas during carbonation curing treatment is
In order to increase the crushing strength of the product, it is necessary to set the content to 3% by weight or more as shown in the figure, and to set the flow rate to 1 cm/see or more in terms of superficial flow rate as shown in Figure 4.

As described above, according to the method of this invention, high-strength agglomerated ore can be produced continuously in a short time, efficiently and economically without firing, and can be used in special environments such as vast curing zones and high-pressure equipment. Excellent industrial effects such as no equipment required are brought about.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the results of water curing treatment according to the method of the present invention, together with comparative examples; Fig. 2 is a diagram showing the crushing strength of products subjected to hydration curing treatment and carbonation curing treatment at the same time, together with comparative examples; Figure 3 is a diagram showing the relationship between the CO2 concentration and the crushing strength of the product during carbonation curing treatment, Figure 4 is a diagram showing the relationship between the flow rate of CO2 gas and the crushing strength of the product, and Figures 5 to 7 The figure is a process chart showing an example of the implementation steps of the method of this invention. In the drawings, 1B, lb, lc...raw material storage bin, 2...mil,
3... Covering tie day, 4... Water curing shaft furnace,
5...Carbonation curing shaft furnace, 6...Stockyard, 7...Shaft furnace, 8...Grate, 9...
Steam blowing furnace, 10... CO□-containing containing gas blowing Applicant: Nihon Koukan Co., Ltd. agent Keitabe Tsutsumi (1 other person) 1) Paddy tai t di Saran bait 1 ′ = U voice distance V n

Claims (3)

[Claims] (1) A method for producing uncalcined agglomerate ore, in which raw pellets obtained by granulating a powdery iron source to which a predetermined proportion of hydraulic binder has been added are subjected to curing treatment to produce agglomerate ore. In this method, the raw pellets are subjected to water curing treatment by injecting saturated steam and carbonation curing treatment by injecting carbon dioxide-containing gas to form high-strength agglomerate ore in a short time. Characteristic method for producing unfired agglomerate ore. (2) The production of non-calcined agglomerate ore according to claim (1), wherein the main wavelet is subjected to the carbonation curing treatment after being subjected to the water curing treatment. Law. (3) A method for producing non-calcined agglomerated ore according to claim (1), characterized in that the water curing treatment and the carbonation curing treatment are simultaneously applied to the chemical ret. .