JPS6223944A - Refining method for nickel oxide or the like - Google Patents

Abstract

PURPOSE:To reduce and recover nickel oxide in ore as ferronickel at a high reduction rate by kneading a carbonaceous material, limestone, etc. which are auxiliary raw materials in the powder state together with water with the nickel oxide ore molding the mixture to briquettes and calcining the briquettes after drying. CONSTITUTION:A large amt. of water is incorporated into the ore contg. NiO such as noumeite and therefore, the ore having the poor dehydratability thereof is crushed in a dry crushing stage A. The ore having the good dehydratability is crushed in a wet crushing stage C. The carboneous material and limestone as the auxiliary raw materials are separately crushed in a dry crysing stage B. The raw materials crushed to <=3mm from the above-mentioned three drushing stages are uniformly mixed in a mixing and kneading stage D so as to contain 0-20% moisture and to contain the carbonaceous material at 2-5 times the ratio necessary for reduction of NiO. The mixture is then molded to the briquettes having 20-30mm diameter in a briquetting stage E. After the briquettes are dried in a grate type rotary kiln F, the briquettes are calcined in a rotary kiln G to reduce the NiO to Ni which is separated and recovered as ferronickel together with Fe in the ore by magnetic sepn.

Description

[Detailed description of the invention]

<Purpose of the invention> Industrial field of application The present invention relates to a method for smelting nickel oxide ore, etc. Specifically, after pulverizing ore such as nickel oxide ore, it is made into briquettes, etc., and then grated, Rotary 4 equipped with a drying/preheating device such as a 17-ft oven: Drying with a run,
The nickel (hereinafter referred to as N) contained in the ore is preheated and fired.
Say 1. ) and other metals are reduced and grown as Luppe (grained iron) and smelted.
In advance, a large amount of RA material and slag-forming agents such as limestone are uniformly added to the dough, and the moisture content is optimized for the dough. The kiln can be fired to promote the formation of 19 yuan and slag of metal materials such as N1, greatly increasing the operational efficiency, greatly saving thermal energy for drying and preheating, and reducing the amount of dust scattered. The present invention relates to a method for smelting Ni oxide ore, which improves productivity. Conventional technology In general, metals such as Ni are essential components for A-suanite stainless steel, and the raw material Ni ore for N1 is usually silicate N1 ore such as garnilite imported into Japan. Ni is smelted from this oxide layer ore. Further, this Ni oxide ore is usually a fine ore containing a large amount of water, and these ores are smelted, for example, as follows. Normally, first, a large amount of water is added to each of the main raw materials and auxiliary raw materials such as ore, carbonaceous material, and limestone, and the slurry is individually wet-pulverized.Then, these raw materials are mixed, and this mixed material is dehydrated. From there, it is made into pellets and other pellets. This mass is then charged into a grate rotary kiln. Therefore, it is dried, preheated, and fired, but the amount of carbonaceous material necessary for reducing Ni and other metals and as a fuel is not included in the aggregate, so carbonaceous material is charged from the outside. These raw materials are dried on a grate, put into a rotary kiln, preheated and fired, and then metals such as Ni are reduced and grown as luppe, which is then discharged as clinker, which is a combination of luppe and slag. ,
Through subsequent processing, ferroalloys such as ferronickel are obtained from this clinker. However, in this method, a large amount of water is added to the main raw material II and auxiliary raw materials17 and wet-pulverized to form a slurry, so the water is removed with a filter etc. after mixing the raw materials, but equipment such as a drum filter is not used. Dehydration is not sufficient, and since each raw material is mixed in a slurry state, it is difficult to mix the raw materials uniformly. In particular, it is difficult to uniformly disperse and mix large amounts of carbon materials with large differences in specific gravity. It's extremely difficult. In other words, Japan Mining Association Journal/971122 ('84-8
) As described on pages 792 to 794, the sheet 70 of the conventional method for smelting Ni oxide ore is as shown in FIG. A large amount of water is added to each of the limestones, which are wet-milled individually in a tube mill to form a slurry containing about 50% water. After that, each slurry raw material is collected in a storage tank, mixed therein, a desired polymer flocculant is added thereto, sent to a drum filter, dehydrated and made into a cake, and then manufactured. It is made into briquettes using a briquetting machine, then dried, preheated, and fired in a grate rotary kiln. However, some ores have extremely poor dehydration properties, but even if the dehydration properties are good to some extent, even if the maximum dehydration is achieved using a drum filter, etc., the water content remains at most around 30%, and a large amount of water remains. Moisture remains and moisture fluctuations are large, and low-pressure molding machines for high-moisture raw materials deteriorate moldability during dough making and require a large amount of thermal energy during drying and preheating. Further, the main raw material and the auxiliary raw material are mixed in a slurry state in a storage tank. However, in a slurry state, there is a large difference in specific gravity and viscosity between these raw materials, so carbonaceous materials inevitably segregate.
It is difficult to mix uniformly, and this non-uniformity becomes an obstacle during reduction firing. Furthermore, since it is difficult to mix uniformly in this way, it is not possible to incorporate too much carbonaceous material into the aggregates such as briquettes, resulting in fluctuations in the carbonaceous content and A fragile compound is easily disintegrated, and this causes so-called rings to occur on the operating surface of a rotary kiln, resulting in a loss of IP smoothness and making it extremely difficult to improve productivity. Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks. Specifically, after pulverizing main raw materials such as N1 oxide ore and auxiliary raw materials such as limestone and carbonaceous materials, When mixing and kneading raw materials, at least the amount of nickel and other metals in the main raw materials must be
! This carbon material and solvent can be uniformly blended as an interior material, and this interior carbon material can be uniformly dispersed and kneaded, and then a composite material containing this large amount of carbon material and solvent can be made. In addition to drying and preheating in a Gray 1 type rotary kiln, reducing metals such as 41Ni and promoting growth as a luppe, improving operational efficiency and productivity, and using a high-pressure dough making machine. To provide a method for smelting nickel oxide ore, etc., which suppresses the moisture content in the ore and makes it strong, reduces the thermal energy used for drying and preheating, and increases production accordingly. <Structure of the Invention> Means for solving the problem and its operation, that is, the method of the present invention includes a pulverizing process of pulverizing main raw materials such as nickel oxide ore, auxiliary raw materials such as limestone and carbonaceous materials, and a process of pulverizing these pulverized materials. A mixing and kneading T culm that is mixed and kneaded in a predetermined amount, a briquetting process that molds the kneaded product into a mass such as a predetermined shape of briquettes, and a drying process that dries this mass using a grate, etc. This oxidation process consists of a firing step in which the dried pellet is charged into a rotary kiln, and while being moved through the rotary kiln, it is preheated and fired to reduce metals such as nickel in the main raw material and grow it as a luppe. In the method for smelting nickel ore, etc., in the pulverization step, the main raw material is divided into at least two parts, one of which is wet-pulverized and the other is dry-pulverized; in the mixing 7nN step, Mixing and homogeneously kneading the main raw material with carbonaceous material and a solvent of at least 100% of the amount necessary for reducing nickel and other metals; In the firing step, the aggregate is preheated in a rotary kiln and then fired so that the metal content such as nickel in the main raw material is reduced by the carbonaceous material contained in the aggregate;
It is characterized by Furthermore, the method of the present invention includes drying and pulverizing main raw materials such as nickel oxide ore and auxiliary raw materials such as limestone and carbonaceous materials in the pulverizing step as described above, and then adding an appropriate amount of moisture to these pulverized materials and kneading them. You can also do that. Now, the structure of this means and its operation will be explained in more detail with reference to the drawings as follows. Note that FIG. 1 is a flow sheet relating to one embodiment of the method of the present invention, and FIG. 2 is a layout diagram of an example of an apparatus for carrying out the method of the present invention. First, as shown in FIGS. 1 and 2, the main raw material, N1 oxide ore, is divided into at least two parts. In this case, it is usually divided into two depending on the quality of dehydration.
One of these ores, that is, the ore with poor dehydration properties, is subjected to a drying and pulverizing process and then pulverized. Further, the other type of ore, that is, the ore with good dehydration properties is crushed through wet crushing step 0. That is, the dry crushing process A is a process of crushing the ore in a dry state, and it can be configured in any way as long as the ore can be crushed to a diameter of about 2 mm or less, but usually, as shown in FIG. It is constructed by connecting a grinder 1, a cyclone 2, and a bag filter 3, and among them, a grinder 11
Dry air is sent from a hot air stove 4 to the hot air stove 4. Therefore, some of the ore usually contains about 20 to 40% water.
The grain size is approximately 0.00 mm, but it is ground in a dry state in a grinder R1 such as a ball mill, adjusted to a particle size of approximately -2 mm, and dried to a moisture content of approximately 10% or less. To explain in more detail, this mill 1 has a powder frame in which hot air is sent from a hot air furnace 4 and the pulverized raw material is discharged together with the hot air.Due to the pulverization under this hot air flow, the particle size becomes homogeneous and Particle size can be adjusted by adjusting the amount of hot air, moisture can be removed sufficiently, and drying can be performed well. Note that after that, this dry crushed ore is recovered by the cyclone 2 and the bag filter 3, and temporarily stored in the storage tank 3'. Further, the wet grinding process G is a process of grinding ore with good dehydration properties into a slurry form, and any structure can be used as long as this process can be realized. Usually, as shown in FIG. 2, it consists of a wet duplex mill 5, a plurality of slurry tanks 6,
A drum filter 7 is connected to this. In other words, ores with poor dehydration properties (which also usually contain 25-40% water,
The particles (with a particle size of about 300 mm) are added with water and pulverized in a wet tube mill 5 to form a slurry containing about 50% water. This slurry is temporarily stored in a slurry tank 6, and then The mixture is sequentially dehydrated using a drum filter I to a moisture content of about 28 to 35% and made into a cake. Incidentally, auxiliary raw materials such as carbonaceous materials and limestone are usually crushed through dry crushing process B, but their crushability is different from that of ores.
Its water content is also lower than that of ore. Therefore, the dry crushing process B is similar to the dry crushing process A, in which a storage tank 9 is connected to a tube mill 8 that does not require sieving, and the tube mill 8 dry-pulverizes the auxiliary material of about 1100 mm, that is, leaves it as it is. The powder is crushed to a particle size of approximately -2 mm, and this is temporarily stored in a storage tank 9. In addition, if the returned dust is to be reused, it can be added in the next mixing and kneading process, but it is better to make it into a slurry in the slurry tank 6 of wet crushing process C and add it to the ore slurry after wet crushing. It can also be made into a cake by dehydrating it with a drum filter 7. Further, the particle size of each pulverized raw material as described above is preferably as small as possible in order to increase the crushing strength of briquettes and the like. From this point of view, in the method of the present invention, the powder is pulverized to about 1-3M. Diameter 3
If it is more than mm, even if pulverization in the subsequent mixing and kneading step is taken into account, briquettes with a predetermined strength cannot be obtained with a good yield (90% or more). Next (=9 As mentioned above, each raw material adjusted to a particle size of about -3 mm is mixed and kneaded in appropriate amounts in mixing and kneading step 0. At this time, the amount of each raw material is 10 to 20%, preferably 15 to 20%, from the viewpoint of moldability of the mass, saving of heat energy for subsequent drying and preheating, etc.
shall be. Further, the amount of charcoal in the auxiliary raw material is at least greater than the amount necessary to reduce the metal content such as N in the total ore, and in particular, the amount consumed in combustion is added in addition to this required amount. That is, a certain amount of moisture is required in order to obtain a predetermined moldability and strength in a dough such as briquettes in the subsequent dough-making process, but too much water is not preferable because it weakens the strength. However, if the moisture content is too high, not only will the dough be difficult to form, but a large amount of thermal energy will be required during preheating and drying.
Due to exhaust gas during reduction firing, drying may not be possible within -1 minute, and from this point of view,

[J is preferably kept at about 20%. In addition, it is important to add a large amount of carbonaceous material to the auxiliary raw materials.
Contain more than the amount necessary for reducing metal components such as 1. In other words, unlike the conventional method, the method of the present invention produces strong briquettes containing carbon and solvent in an amount greater than that required for reducing the metal content, and this point is one of its characteristics. ing. In short, if we only install one pitirAo internally to correspond to the required amount of reduction of metals such as Ni, about 50% to 80% of the carbonaceous material in the interior will inevitably be consumed for combustion, and the metals will be reduced. There is a shortage of carbon material necessary for reduction. For this reason,
The amount of carbonaceous material needs to be greater than the amount necessary to provide metals such as reduced Ni, and although it depends on the operating conditions, in reality, 2 to 5 times the amount is required. be. In addition, in the mixing and kneading step 0, a large number of carbon materials are blended in this way, and the moisture content is adjusted as described above.
This large amount of carbon material needs to be uniformly dispersed. That is, after kneading the raw materials, for example, as described below, the diameter is 20 to 30 mm.
The briquettes are made into billow-shaped or almond-shaped briquettes of III-1 consistency, but if moisture and interior materials are unevenly present at this time, the strength of the briquettes decreases. For this reason, it is necessary to knead more roughly than in the conventional example. From this point of view, in the method of the present invention, as shown in FIG. 2, a mixing IM 110 such as a bag mill and a kneading machine 11 such as a rod mill are connected in series. establish a base In this way, if the raw materials are mixed in advance in the mixer 10 such as a bag mill, and then slightly crushed and kneaded in the kneader 11 such as a rod mill, the particles in each raw material that have already been crushed will be further crushed by the rod mill or the like. As it is granulated, it is stirred and kneaded uniformly, water and carbonaceous materials are uniformly dispersed, and the property of making agglomerates is improved. Note that the specification of Japanese Patent Publication No. 43-6256 describes that the rod mill is used not only for grinding but also for kneading. However, when manufacturing powdered iron ore pellets, this technology directly connects a ball mill and a rod mill, and these mills have not only a grinding function but also a kneading function. This technology differs from the technology using a kneader and a crusher because of the dispersion of a large amount of carbonaceous material into the interior. In other words, the technology shown in the above specification is based on the premise that powdered iron ore is crushed and then pellets are manufactured through processes such as kneading, water addition, and granulation. This process is omitted and a certain degree of grinding and kneading are performed simultaneously using a ball mill and a rod mill. In other words, while a normal pellet manufacturing process involves a crushing process and a kneading process, the above technology uses a ball mill and a rod mill to crush and knead the powdered iron ore without crushing it in advance.
The feature is that this is done in a wet state, and a kneading machine such as a bag mill is not used. In contrast, in the method of the present invention, the raw materials are dry-pulverized, wet-pulverized, etc. before being kneaded, and a large number of auxiliary raw materials are uniformly blended. As the kneading equipment, a mixer such as a bag mill is used, followed by a kneader such as a rod mill. To explain in more detail, first, as shown in Figure 2,
The mixture is kneaded to some extent using the mixer 10. Therefore, by this mixing, the auxiliary materials are uniformly dispersed and mixed considerably. next,
This mixed state is further kneaded using a rod mill with a coarse crushing function. In this kneading, the falling of the rod actually promotes the kneading. The uniformly kneaded material is temporarily stocked in the raw material yard 12 and sent to the next step E as required. In addition, in the above, the wet pulverized raw materials and the dry pulverized raw materials were blended under the above conditions, but this does not necessarily mean that the pulverization is divided into wet and dry pulverization (or even if all the raw materials are dry pulverized). However, it is also possible to mix these raw materials as described above and add about 10 to 20% water and knead them.Next, in the mulch T culm, It is molded into a mass such as briquettes.The shape of this mass may be, for example, a pellet, but it is usually 20 mm in diameter.
Form into bi- or almond-shaped briquettes with a thickness of ~6 om. Such billow or almond-shaped briquettes dry extremely well in the next grate, with almost no pulverization at this time, and the heat energy required for drying can be significantly reduced. Next, the process moves to a baking process G through a drying process. The drying step F is carried out in the grate 13 of the gray 4 type rotary kiln as shown in FIG. 2, and the firing step is carried out in the Gμ rotary kiln 15. In the grate type rotary kiln shown in Figure 2, the first grate 13
The scraps from the rotary kiln 15 are introduced from above the grate 13, and the pellets are dried. At this time, since the aggregates such as Brichella have a billow or almond shape, they can be dried very well, and the moisture content is also appropriate, making the aggregates even stronger as they dry. and will not turn into powder. To explain in more detail, the aggregates such as Brichella]-
As mentioned above, it contains a large amount of carbonaceous material, and the water content is 10 to 20%, which is relatively small. For this reason, when drying on gray 1 to 13, the temperature increases almost linearly from room temperature to about 400°C. On the other hand, as shown in Fig. 3, Briquella molded according to the conventional example has a high moisture content and poor moldability, so even if it is dried on a grate as described above, BN heat can only be raised to about 200°C at most, and preheating in the rotary kiln requires a long time. After drying, the pellets are fed into the charging end of the rotary kiln 15 through the discharged ore cycoat 14, and preheated in the rotary kiln 15 with nails. It is reduced while being surrounded by carbonaceous materials, and when this metal component approaches the discharge end of the rotary kiln 15, it grows as luppes (that is, metal grains), and these luppes are included in the slag and are discharged as clinker. . Note that after clinker is discharged, it is cooled and separated, usually by magnetic separation or other means, and recovered as a ferroalloy such as ferronickel. In addition, the dust generated during drying in a grate and the dust generated during firing in a rotary kiln are reduced as described below, but these dust [・ are as described above in the wet pulverization process.
returned and reused. In addition, the rotary kiln has the same structure as the conventional example,
A conventional through burner 16 is installed at the discharge end, and fuel such as pulverized coal, heavy oil, or gas is burned in this burner 16, and raw materials such as pellets are heated and starved in the rotary kiln by this thermal energy. In addition, in this rotary kiln 15, the temperature of the dough is sequentially increased as it progresses from the charging end to the discharge end, and is heated to about 400° C. on the grate 13, so that almost no attached moisture is left. Therefore, the material temperature increases linearly and by a small amount (e.g.
At a point 35m from the charging end, reduction progresses extremely well, partly because there is a large amount of carbonaceous material inside. As the reduction progresses in this state, the oxygen partial pressure in the raw material layer decreases, and FeO and the like increase. This I”e
When O is combined with, for example, 5in2, there is a risk that a low melting point compound such as fayalite will be formed and grow as a ring on the inner wall of the rotary kiln. This phenomenon is particularly likely to occur when powdered raw materials are used, and this is a major obstacle in the operation of conventional rotary kilns. However, in the method of the present invention, the generation of powder raw materials is suppressed to a low level due to the strong briquette strength, so that rings are difficult to form and the furnace can be operated very smoothly. Generally, in pellets as an iron source, it has been conventional practice to incorporate as much carbon material as possible into the pellets and use pulverized coal instead of petroleum-based energy. By the way, in 19821 No. 15, pp. 2231-223I and 2238-2245, there is a report on iron and copper box 68 (No. 15, 19821, pp. 2231-223I and 2238-2245) that states that as one of the means of converting from petroleum-based energy to coal-based energy due to the oil crisis, Pellets containing up to 1% of pulverized coal are disclosed.These pellets do not directly reduce metal components such as e with the inner coal, and this inner coal is only used as a fuel.Also, These pellets are made into iron ore in a blast furnace, and the amount of carbonaceous material contained within the blast furnace must be such that it does not become powder in the blast furnace.
J? It is determined within a range that does not impair A degree or drop strength,
It remains within 1% at most. On the other hand, the method of the present invention uses a rotary gill as a reactor corresponding to a blast furnace, and promotes the reduction of metals such as old metals. In other words, the amount of carbonaceous material is increased as much as possible to form a state in which the metal components and ore particles are surrounded by the carbonaceous material, and are quickly and smoothly reduced by gas reduction. EXAMPLES Next, examples will be explained. Example 1 First, oxidized N1 ores A, B, and C having the composition shown in Table 1
. Divide D into two, the first group has 3 ores (A) in dry weight.
80kl;l, ore (B) 50klJ, ore (D) 12
Blended as 0kq, with an average particle size of 300mm or less (maximum 4
00 mm1, and was subjected to dry pulverization in the dry pulverization process shown in FIGS. 1 and 2. The second group is ore (B) 250
kq, ore (0) was blended as 200 kQ, and wet-pulverized in wet-pulverization step C to the same particle size as the first group. At this time, in the first group, the ore is dried and crushed at the same time by hot air sent from a hot air stove in a ball mill.
At this time, the particle size after pulverization is adjusted by listening to hot air and pulverized to about 12 mm, dried to a moisture content of about 5%, and the pulverized ore is stocked in a storage tank. In addition, in the second group, water was added until the total water content was about 50%, and the slurry was made into a slurry with a wet tube mill.
1Ij! After grinding, store it in a slurry tank.
Return to this Das l- (composition shown in Table 4) 751<q
was added, and then dehydrated using a drum filter to obtain a moisture content of 30%. The auxiliary raw materials are charcoal material and limestone that are pulverized in the dry pulverization process.
kg was continuously ground in a duplex mill to a particle size of -2mm,
The water content was 6.1%. However, the carbonaceous material (81 is "-xbreeze").Table 3 Composition of Limestone (wt%) Next, these respective crushed raw materials are mixed, and at this time, each crushed raw material has a moisture content of 17 to 19% and charcoal. The amounts were determined and kneaded in a mixing and kneading process to obtain 130 kg of limestone and 70 kQ of limestone.In this process, a bag mill and two rod mills were connected to uniformly knead water and a large amount of carbon material. After that, the kneaded raw materials are processed into a dough with a diameter of 4 in the dough making process.
It was molded into a billow-type briquette 1~ of about 0s. When this briquette was repeatedly dropped from a height of 2 m five times to perform a drop test, more than 95% of the briquettes remained unbroken. Next, the Brichera] is transferred to the drying process E, and the Grate (
This drying was carried out by introducing exhaust gas (550° C.) from a rotary kiln in a countercurrent flow. At this time, the temperature of the briquettes at the outlet of the grate reaches 390 degrees Celsius, and the briquettes are dried very well, without becoming powdered due to bursting, etc.
The amount of recycled waste recovered was 42 kg. Next, after drying, a rotary kiln (length 70 mm) is placed from the charging end.
m), preheated and fired. At this time, the temperature of the briquettes decreases linearly as it progresses through the rotary kiln, and from the charging end to 2011
1 (At 50 m1 from the discharge end, the temperature reaches 700 °C and the crystal water begins to decompose. After that, reduction progresses, and the temperature reaches 1320 °C at 10 m from the discharge end. The same temperature was maintained in the Ruppe production zone between the two, and sufficient Ruppe growth was observed.
The reduction rate of Ni was 96.5%. For comparison, the above-mentioned auxiliary raw materials were added in a slurry tank to the slurry-like ore wet-milled in the second group with a water content of 50%, and mixed so that the carbonaceous material contained therein was 80 klJ. However, in the slurry tank, there was a lot of segregation and it was difficult to mix uniformly. Therefore, this slurry was dehydrated using the drum filter mentioned above to a consistency of 30% moisture and culm, and this cake was shaped into a cake with a diameter of 12 mm +
It was made into a briquette. Because there is a lot of moisture during this dough making,
The briquette making machine was heated by steam, and the briquette was then dried on the above-mentioned grate.However, the formability of the briquette was also poor (moisture content was 15%).
This was placed in the rotary kiln mentioned above, and preheated and fired in the same manner as described above. At this time, since the amount of carbon material inside was small, 80 kg was charged as an exterior material, preheated and fired in a rotary kiln. A comparison of the conditions at this time is shown in Table 5.Furthermore, based on the above results, oxidized N1 ore was actually treated using the method of the present invention and the comparative example, and the operational results were compared. The results were as shown in Table 6 per ton of dry ore. Table 6 Example 2゜Different from Example 1, the ores of the second group were also dried and crushed in the same manner as the first group, and the auxiliary materials were added to the dry and crushed ores in the same manner as in Example 1, After this blending and kneading, water was added to obtain a kneaded raw material as in Example 1. After that, it was made, dried, preheated, and fired in the same manner as in Example 1, and the same results as shown in Table 5 were obtained. Example 3゜The three types of pulverized raw materials obtained in Example 1 were mixed with a moisture content of 18.5
%, and when kneading after blending so that the amount of carbon material is 130 klJ, the kneading equipment is (a) only a rod mill, (b) only a bag mill, (c) when three bang mills are used, (d) a bag mill and a rod mill. When these were combined, the dispersibility of water and carbonaceous material and the moldability during making were determined using the following formula. As a result, even if only a rod mill was used as in (a), the water content was around 18.5%, so the water and carbonaceous material could be uniformly dispersed and kneaded, but the yield of briquettes was not sufficient. . In addition, when only a bag mill was used as in (b), cake-like particles remained in the kneaded material, resulting in insufficient kneading. Therefore,
When three bag mills were used as in (c), the molding yield was quite poor due to insufficient kneading for the same reason if only the bag mill was used. Furthermore, when a bag mill and a rod mill were combined as in (d), the dispersibility of water and carbon material was good (and the kneading was extremely good) because the mixture was mixed in the bag mill beforehand and then kneaded in the rod mill. , as in (a), (c), and (d), kneaded raw materials (
When briquettes with a diameter of 40 mm were prepared with a total moisture content of 4118.5% and subjected to a drop test, the results shown in FIG. 4 were obtained. In this test, the specimen was repeatedly dropped from a height of 2 m onto a concrete floor 5 times, and the incidence of cracks of 5 mm or less at this time is shown in the cross-hatched area, and the incidence of cracks is shown in the shaded area. From this result, it was found that case (d) was the most effective with a yield of 96%. <Effects of the Invention> As explained in detail above, the present invention is capable of crushing a part of the main raw materials when pulverizing the main raw materials such as nickel oxide ore together with the bed material and auxiliary raw materials such as carbon material. Wet-mill, then dry-mill the other main raw materials, dry-mill the auxiliary raw materials, and then mix and knead these pulverized materials. During this mixing and kneading, the moisture content is within the appropriate range and the main raw materials are mixed. The carbonaceous material and limestone of a certain amount necessary for reducing nickel and other metals are mixed and kneaded uniformly. Therefore, the aggregates such as briquettes formed from this kneaded material are wrapped in inner carbon material in the rotary kiln, metals such as nickel are reduced, and furthermore, this inner carbon material is heated sufficiently in the Ruppe generation zone. Give energy 1:
Therefore, the metal component grows well as a luppe. Furthermore, there is no generation of rings or the like during operation, and the operation is stabilized, and the amount of ore processed is increased due to the decrease in water content, which reduces thermal energy. Also, during pulverization, the main raw material is divided into at least two parts, one of which is wet-pulverized, and the other is dry-pulverized.
When these amphoteric raw materials are mixed and kneaded, there is no need to add water during mixing and kneading, and even when the main raw materials have poor dehydration properties, they can be used without any problems. Further, when a bag mill and a rod mill are used during kneading, even water and a large amount of carbonaceous material can be mixed uniformly, and briquettes with a predetermined strength can be molded with a high yield.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet according to one embodiment of the method of the present invention,
Figure 2 is a layout diagram of an example of a device for carrying out the method of the present invention;
The figures are flow charts 1 to 1 of an example of a conventional method for smelting nickel oxide ore, and FIG. 4 is a graph showing the relationship between various kneading methods and the drop test results of the obtained briquettes. Code 1... Autogenous grinding mill 2... Zyclone 3... Bag filter 3'... Storage tank 4... Hot air stove 5
...Wet tube mill 6 ... Slurry tank 7 ... Drum filter 8 ... Rod mill 9 ... Storage tank 1
0...Mixing machine such as bag mill 11...
Mixing mR12 such as rod mill etc. Raw material yard
13'...Danking machine 13...Gray]
・１４・・・・・・１１ Sikote １５・・・・・・Rotary kiln １６・・・・・・Barbu Patent applicant Nippon Yakin T Gyo Co., Ltd. Agent Patent attorney Yoshikatsu Matsushita Lawyer Soejima Sentence String 68 Tomi, Σ Mi a 0

Claims (1)

[Scope of Claims] 1) A pulverizing process for pulverizing main raw materials such as nickel oxide ore and auxiliary raw materials such as limestone and carbonaceous materials, a mixing and kneading process for blending and kneading these pulverized materials in predetermined amounts, and There is a step of forming the kneaded material into a mass such as briquettes of a predetermined shape, a drying step of drying the mass on a grate, and a step of charging the dried mass into a rotary kiln. A smelting method for nickel oxide ore, etc., which comprises a firing step in which metals such as nickel in the auxiliary raw material are reduced by preheating and firing while the nickel oxide ore is transferred, and the nickel oxide ore is grown as a luppe. The raw material is divided into at least two parts, one of which is wet-pulverized and the other is dry-pulverized, and in the mixing and kneading step, the amount of the main raw material is more than the amount necessary to reduce nickel and other metals. In the agglomeration step, the auxiliary raw materials are agglomerated; In the firing step, the agglomerate is preheated in a rotary kiln and then kneaded uniformly. The method is characterized in that metals such as nickel in the main raw material are reduced with the carbonaceous material contained in the composite, and the raw material is made into slag using the contained solvent, and the reduced metal is grown as a slag. A method of smelting nickel oxide ore, etc. 2) A pulverization process in which main raw materials such as nickel oxide ore and auxiliary raw materials such as limestone and carbonaceous materials are pulverized, a mixing and kneading process in which predetermined amounts of these pulverized materials are blended and kneaded, and the kneaded product is shaped into a predetermined shape. There is a step of forming a lump into a dough such as briquettes, a drying step of drying the dough on a grate, and a step of charging the dried dough into a rotary kiln.
In the smelting method for nickel oxide ore, etc., which comprises a reduction step of preheating and firing while moving through the rotary kiln to reduce metals such as nickel in the main raw material and grow it as a luppe, in the pulverization step. drying and pulverizing all of the main raw materials; in the mixing and kneading step, a solvent such as carbonaceous material and limestone is mixed with the main raw materials in an amount greater than the amount necessary to reduce nickel and other metals; Adding 20% moisture and kneading; In the agglomeration step, a mixture of auxiliary raw materials; In the firing reduction step, the agglomerate is preheated in a rotary kiln, and then the agglomerate is Nickel oxide is characterized by reducing metals such as nickel in the main raw material with the carbonaceous material contained inside, and converting the raw material into slag with the contained solvent, and growing the reduced metal as a slag. A method of smelting ores, etc.