JPS60150856A - Flotation method of iron ore - Google Patents

Abstract

PURPOSE:To separate and concentrate iron ore efficiently from a low grade iron ore contg. iron mineral and alkali-contg. iron silicate-contg. mineral by a flotation process using an amine collector and a depressant comprising starch and adjusting the pH of pulp to a specified value. CONSTITUTION:Flotation of iron-contg. silicate mineral contg. alkali and simultaneous settling of iron mineral are performed by using raw material comprising pulverized low grade iron ore contg. iron mineral and iron-contg. silicate mineral contg. alkali, a collector comprising amine collector (e.g. dodecylammonium chloride), a depressant comprising starch, and adjusting the pH of the pulp to 7- 11.2. Preferred concn. of the collector is 6.9-20.8mg/l, and preferred concn. of starch is 7.5-75mg/l (namely, 100-1,000g per 1 ton of the ore). As the result, above described low grade iron ore which has not been utilized generally for the raw material of iron manufacture has been brought into practical industrial use.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently separating and concentrating iron minerals from low-grade iron ore containing iron minerals and alkali-containing iron-containing silicate minerals by flotation.

In order to effectively utilize low-grade iron ore as a raw material for steel manufacturing, it is necessary to separate and concentrate iron minerals to increase the iron content. For example, gravity beneficiation methods such as table, cyclone, spiral, and cone classifiers, Iron content is concentrated by a magnetic beneficiation method using a low magnetic force magnetic separator or a high magnetic force magnetic separator, a flotation method in which iron ore or gangue minerals are suspended, and the like. By the way, most of the gangue components in low-grade iron ore conventionally used as a raw material for steel manufacturing are mainly quartz, so the method described above makes it possible to efficiently separate and separate iron minerals.
I was able to concentrate it. On the other hand, with the decline in iron mineral resources, it is necessary to use low-grade iron ore as a raw material.Recently, low-grade iron ore containing alkali-containing iron-containing silicate minerals such as pyroxene has been used as a raw material for steel production. There are also movements to use it. However, if such alkali-containing minerals remain unseparated and are mixed into iron minerals, especially when they are formed into pellets as raw materials for blast furnace charging or directly as raw materials for steelmaking, the volume of the pellets decreases during the reduction reaction stage. This causes problems such as expansion, resulting in a significant deterioration in strength, progressing to pulverization, decreased air permeability, and significant impediment to blast furnace operability. Incidentally, Figure 1 shows the relationship between the alkali content in the fired pellets and the volumetric expansion coefficient (SwaltingI) during the reduction reaction.
This is a graph showing the relationship between Nap O (ndex), specifically, the fired pellets obtained by adding 0.75% by weight or less of Nap O to ordinary iron minerals (no alkali) and firing at 1280°C for 10 minutes. 900℃, CO/N2-30/
70, which shows the volume expansion coefficient when the reduction reaction was carried out at a gas flow rate of 1.41/min. As is clear from this figure, the volume expansion coefficient increases as the amount of Na2O in the pellet increases, but this increasing tendency becomes more pronounced as the reduction rate increases, and when the reduction rate is 60%, the amount of Na2O is 0. Even at 55J, the volume expansion is approximately 400%. Furthermore, a very small amount of Na,
Even if the amount of O is 0.2 inches, for example, the reduction rate is about 100 inches.
% volumetric expansion rate. The current standard for volumetric expansion of iron ore pellets as blast furnace charging raw material is 14 or less, so even the presence of even a very small amount of alkali-containing minerals will make them unsuitable as blast furnace charging raw material. 7ru.

Furthermore, it has been confirmed that alkaline substances such as Na2O are volatilized by the heat during the reduction reaction and significantly corrode the furnace walls, so from this point of view as well, mixing of alkaline substances must be avoided at all costs. For this reason, iron ore containing alkali substances has rarely been used as a raw material for charging blast furnaces, but due to the raw material circumstances described above, even low-grade iron ore containing alkali-containing iron-containing silicate minerals has been used. For this reason, it is necessary to remove alkali-containing iron-containing silicate minerals from various low-grade iron ores as completely as possible, and efficiently separate and concentrate them as high-grade iron ores. It is necessary to establish the technology to obtain it.

The present invention was completed as a result of various studies under such circumstances, and its composition consists of finely pulverizing low-grade minerals containing iron minerals and alkali-containing iron-containing silicate minerals, and using amines as a collector. The main feature is that alkali-containing iron-containing silicate minerals are suspended while the iron minerals are sedimented and separated by using a system collecting agent and starch as an inhibitor to adjust the pH of the pulp to a range of 7 to 11.2. It is.

In the present invention, the alkali-containing iron silicate mineral is mainly alkali pyroxene, especially pyroxene cb-g1rlne.
: Na Fe Si, 06), but it is also called Aeg (line Augi pyroxene) and Aeg (line Augi pyroxene)
te: (Na+Ca) (Fe"+Fe"tMg+AI)
(Si, 0.):] The composition between Na,
The content of 0 is about 11-14°5%.

On the other hand, iron minerals are contained in the form of hemite, magnetite, and monite, but the pyroxene mentioned above is widely dispersed in these iron minerals and gangue components, so iron minerals can be efficiently separated from pyroxene and gangue components. - In order to concentrate, low-grade iron ore must first be pulverized, and the flotation method is considered to be the optimal method for separating and concentrating the active ingredients from such pulverized material. In order to investigate the possibility of separating pyroxene from hematite and limonite by flotation, we investigated the flotation properties of each component when using various scavengers and varying the pulp pH. We conducted basic experiments. In other words, each mineral is obtained by using pyroxene with the composition shown in Table 2 and hematite and limonite with the composition shown in Table 3, and by changing the pH of the pulp and the type of collector using a Halmond tube. The floating rate of the powder was investigated. As is clear from Table 2, S02 occupies approximately 50 or more parts of pyroxene, and it is assumed that it exhibits floating behavior similar to that of quartz, so in this experiment A flotation test was conducted on the alkaline side using an amine collector.

Table 3 Hematite and Limonite As a result, if an amine-based scavenger is selected as the scavenger and the pH is set in the range of 7 to 11.2, at least pyroxene can be suspended well. confirmed. However, under such conditions, hematite and monite also float well, making it impossible to achieve the original purpose of separating and removing pyroxene. Therefore, it is necessary to establish a technology that can separate and remove only pyroxene to the floss side or the sink side. Therefore, we targeted pyroxene, hematite (1), and quartz (α-8f02), which accounts for most of the gangue components, and used dodecylammonium chloride (CI21H26) as a scavenger.
Using NHsC1 (hereinafter abbreviated as DAC), the pH was set in the range of 9 to 9.5 where a high level of buoyancy was obtained, and the buoyancy rate of each mineral was investigated when the concentration of the scavenger was changed. The results are as shown in Figure 2. At low concentrations, quartz floats well, as the DAC concentration increases, hematite (1) and pyroxene float, and as the concentration further increases, finally Limonite floats. As is clear from this result, quartz and limonite can be separated from pyroxene by adjusting the scavenger concentration, but for hematite, the optimal scavenger concentration also overlaps with that of pyroxene. , it is not possible to efficiently separate the two. This tendency is similar not only to DAC but also to other amine-based scavengers such as alkylamine salts, alkyltrimethylammonium chlorides, dialkyldimethylammonium chlorides, alkylpyridinium halides, and alkyldimethylbenzylammonium chlorides. confirmed.

Therefore, we thought that if we suppressed the separation of hematite with an inhibitor, it would be possible to float and separate only the pyroxene, so we proceeded with experiments using starch as an inhibitor. That is, a complex ore containing iron minerals and pyroxene (T-Fe: 26.10 cm, particle size near 4 μm throughout) was used as a sample ore, and a flotation experiment was conducted using an MS type flotation machine (capacity 200 cc). .

However, the pH was set to about 11, which allows the pyroxene to float well, the concentration of the scavenger (alkyl diamine acetate) was 0 to 27.6 rng/l, and the concentration of the inhibitor (starch) was 5 to 5.
It was varied in the range of 0ff1g/(100 to 1000g/). The results are as shown in Figure 3, and when an appropriate amount of starch is used as an inhibitor, floating of iron minerals can be suppressed and the iron concentration in the sink can be increased to 40 parts or more. Also, as is clear from Figure 3, the preferred concentration of the scavenger is in the range of 6.9 to 2o, smrt/1, and the preferred concentration range of starch, which was confirmed in a separate experiment, is 7.
．． 5 to 75 rng/l (100 to 100 rng/l per ton of ore)
(equivalent to 0 g).

Table 4 also shows the results of a flotation test for complex ores using a Kyoto University-style compact flotation machine (cell capacity: 500CC) using DAC as a scavenger and starch as an inhibitor. It is something.

As is clear from Table 4, the T-Fe of the sink obtained when no inhibitor was used was 58.56%, the weight ratio was 8.56%, and the Fe distribution ratio was extremely extreme at 12.95%. However, when combined with an appropriate amount of starch, the T-F of the sink is low.
e is 59.24%, the weight ratio is 59.21 inches, and F
The actual yield of e has increased dramatically to 88.77%.

The present invention is constructed as described above, but the point is that finely ground low-grade iron ore containing an alkali-containing iron-containing silicate such as pyroxene is used together with an amine-based collector and starch as an inhibitor. By flotation, only alkali-containing iron-containing silicates are selectively floated, and high-grade iron ore can be concentrated and recovered on the sink side. As a result, it has become possible to commercialize the aforementioned low-grade ore, which has not been used much as a raw material for iron production, and the reserves of high-grade iron ore are becoming increasingly depleted. This will make a significant contribution to responding to the current situation.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the amount of Net:O in iron minerals and the coefficient of volume expansion, Figure 2 is a graph showing the relationship between the suspension rate of various minerals and the concentration of the collector, and Figure 3 is a graph showing the relationship between the volumetric expansion coefficient and the amount of Net:O in iron minerals. It is a graph showing the relationship between the concentration of a collecting agent used as a flotation sample and the Fe concentration in a sink. Applicant Kobe Steel, Ltd.

Claims (1)

[Claims] Low-grade iron ore containing iron minerals and alkali-containing iron-containing silicate minerals is finely pulverized, and an amine-based collector is used as a collector, and starch is used as an inhibitor, and the pulp pH is adjusted to 7 to 11.2. A method for flotation of iron minerals, which comprises suspending alkali-containing iron-containing silicate minerals and separating the iron minerals by sedimentation.