CN1089374C - Process for separating titanium component from titanium-contained slags - Google Patents

Abstract

A method for separating titanium components from titanium-containing slag comprises three steps of selective enrichment, selective growth and selective separation. First modify the slag, adjust the composition of the slag, control the oxygen position of the slag to selectively enrich the titanium in the slag into the perovskite phase; then control the cooling speed and temperature range during the cooling process, and add a small amount of additives, Promote the growth and coarsening of the precipitated perovskite phase; finally, the slag is crushed and ground, and the titanium-rich phase enriched in perovskite is selectively separated by mineral processing methods. The invention has the advantages of less investment, large processing capacity, low energy consumption, high benefit, easy industrialization, comprehensive utilization of resources, and elimination of environmental pollution.

Description

Method for separating titanium components from titanium-containing slag

The invention belongs to a mining and metallurgy process method, in particular to a method for separating titanium components from titanium-containing slag.

Vanadium-titanium magnetite is one of the abundant polymetallic paragenetic ores in China, which contains 30-45% iron and 6-15% TiO ₂ . The composition of the ore is complex, and the embedded particle size is fine. The effect of direct ore dressing to separate iron and titanium is not good. With pyrometallurgy, slag-iron separation can be achieved after smelting in the metallurgical furnace, but most of the titanium-containing oxides are stored in the slag phase in a very fine and dispersed state, becoming titanium-containing metallurgical slag. In the prior art, there are also methods of separating titanium from titanium-containing slag by using pyrometallurgy, hydrometallurgy, or mineral separation, but due to low separation efficiency, small processing capacity, environmental pollution, long process, large investment or low benefit And other reasons, finally all can not be applied on the industrial scale, pile up in large quantities so far, not only waste resources, but also pollute the environment.

The purpose of the present invention is to provide a method with low energy consumption, high benefit, low investment and large processing capacity, which can effectively separate the titanium component from the titanium-containing waste residue.

The basic content of the present invention is to firstly modify the titanium-containing slag, adjust the composition of the slag, control the oxygen position of the slag, and selectively enrich the titanium dispersed in various titanium-containing phases in the slag into a titanium-rich Mineral phase——in the perovskite (CaTiO ₃ ) phase, and optimize the treatment conditions in the subsequent cooling process, control the cooling rate and temperature range, add a small amount of additives, and promote the growth and coarsening of the precipitated perovskite phase, reaching the average The particle size is more than 50 μm, and then the slag is crushed and ground, and the titanium-rich phase rich in perovskite is selectively separated by mineral processing methods. The method of the present invention mainly consists of three steps of selective enrichment, selective growth and selective separation.

Selective enrichment: The distribution of titanium in titanium-containing slag is very dispersed, and there are at least five titanium-containing mineral phases in the slag, as shown in Table 1.

Table 1. Distribution of titanium-containing mineral phases in titanium-bearing blast furnace slag mineral perovskite Titanium pyroxene Titanium-rich diopside Magnesia alumina spinel Ti(C,N) solid solution Distribution of _TiO2 in slag % 14.30 62.87 14.20 0.1 0.33 _TiO2 content % in mineral phase 53.94 13.96 19.49 2.23 93.45 In order to solve the "dispersion" problem, it is critical to adjust the composition and properties of the slag. Selective enrichment is to add one or more _{metallurgical} wastes containing oxides CaO, _SiO2 , _Al2O3 , MgO, _FeOx , MnO2 _, etc. Dust, tailings, waste slag, etc.), the slag basicity R (R=CaO/SiO ₂ ) can be adjusted between 1-2, and the addition amount is 5-15% of the total slag. In order to maintain the oxygen position, the oxygen partial pressure is maintained in the range of 10 ^-6 -1atm by blowing air or oxygen into the slag. Always controlling the basicity and oxygen position in the selective enrichment process is a necessary condition to promote the enrichment of titanium dispersed in the slag into the perovskite phase and increase the precipitation of the perovskite phase. Selective growth: The perovskite phase in the untreated titanium-containing slag is very small ((10μm), which cannot meet the particle size requirements for mineral separation. In order to solve the "fine" problem, it is necessary to optimize the treatment conditions to promote the growth of perovskite in the slag. Mineral phase growth and coarsening. When the slag is cooled at a temperature range of 1500°C-1200°C, the cooling rate is between 0.5-5°C/min, and 1-3% of additives are added at the same time to adjust the slag structure and change Perovskite phase precipitation morphology. Additives contain one or more of the following compounds: Cr ₂ O ₃ , MnO ₂ , CaF ₂ , P ₂ O ₅ , si ₃ N ₄ , SiC, TiC, FeS, MnS, NiS , TiN, etc. In order to ensure that the slag reaches the above-mentioned cooling rate, the slag tank needs to be covered, and the side wall is filled with insulation materials. Selective separation: test the physical parameters of the calcium-neodymium ore phase: the specific gravity is 4.1g/cm ³ , the specific magnetic susceptibility 38.94×10 ^-6 BGSM·cm ³ /g. The perovskite phase is the heavier mineral phase in the slag and has weak magnetic properties. Gravity separation or gravity separation combined with magnetic separation and flotation or gravity separation-flotation-electric separation The combined method separates the perovskite phase in the slag, and can achieve the purpose of separating titanium-rich components (>35% TiO ₂ ) and titanium-poor components (<10% TiO ₂ ).

Further describe content of the present invention with accompanying drawing and embodiment below:

Fig. 1 is the block schematic diagram of the technological process that the present invention separates titanium component from titanium-containing slag,

Fig. 2 is the relationship diagram of perovskite phase precipitation amount and basicity,

Fig. 3 is a micrograph of the blast furnace slag of China Panzhihua Iron and Steel Company,

Figure 4 is a comparison diagram of the micromorphological changes of the perovskite phase before and after the addition of additives;

Fig. 5 Flowchart of separation principle of perovskite phase separation from cinder.

Example 1, the composition of the original blast furnace slag is shown in Table 2.

Table 2. The original composition of titanium-bearing blast furnace slag Element TiO ₂ SiO ₂ Al ₂ O ₃ CaO MgO TF % 24.38 17.60 14.59 20.34 8.20 8.48

Selective enrichment is carried out first: in order to adjust the composition and properties of slag, steel slag is added, and its composition is shown in Table 3.

Table 3. Composition of steel slag Element TiO ₂ SiO ₂ Al ₂ O ₃ CaO MgO TF % 1.38 8.54 0.41 53.30 7.66 15.25

The purpose is to promote the reaction (1) of forming the perovskite phase (CaTiO ₃ ) in the slag to the right

(1) To promote the precipitation of the perovskite phase (CaTiO ₃ ), increase a _(CaO) in the slag, and Activity is necessary. However, there are still (MgO), (Al ₂ O ₃ ) and (SiO ₂ ) components in the slag, and other side reactions can also occur, such as the formation of diopside (CaO·MgO·2SiO ₂ )

(2) and generate calcium aluminosilicate (CaO·Al ₂ O ₃ ·SiO ₂ )

(3) Each of the above reactions can occur in slag. There is competition among them. In order to ensure that the reaction (1) is fully carried out, on the one hand, it is necessary to increase the activity of calcium oxide a _(CaO) , and at the same time reduce the activity of silicon oxide In order to inhibit the progress of reactions (2) and (3). Therefore, it is very necessary to increase the basicity R (R=CaO/SiO ₂ ) of slag, but the basicity is too high. The viscosity of the slag also increases exponentially, which is not conducive to the mass transfer in the slag. It hinders the subsequent "selective growth", so the alkalinity should be controlled within a certain range, and the experiment has determined that R=1-2 is the best. In this embodiment, R=1.2 is controlled. On the other hand, blast furnace slag is a reducing slag, and titanium can exist in several valence states in the slag: Ti ²⁺ , Ti ³⁺ , Ti ⁴⁺ , which means that titanium is dispersed in several titanium-containing phases in the slag. one of the reasons. In order to enrich the titanium in the slag as much as possible into the CaTiO ₃ phase, the low-valent titanium Ti ²⁺ and Ti ³⁺ in the slag must be oxidized as much as possible to Ti ⁴⁺ and enter the CaTiO ₃ phase. Controlling the slag oxygen level is another necessary condition.

The above is the principle basis for the selective enrichment in this embodiment. The implementation method is to adjust the composition of the slag and increase the alkalinity by adding CaO to the slag to increase the activity of CaO in the slag. There are many materials containing calcium oxide. Considering that the steelmaking slag is a high-basic slag, usually R>5, the CaO content is above 50%, and the steel slag is an oxidizing slag, which is conducive to the oxidation of low-valent titanium. Furthermore, steel slag is metallurgical waste, and steel slag is used to adjust the composition of molten slag, and the cost is low. Steel slag adding method: it can be crushed and added to the slag ditch when the blast furnace slag is discharged, or it can be added to the slag tank to increase the oxygen level of the slag: it can either inject oxygen or air into the slag , the time is 1-10 minutes, and the broken steel slag can also be mixed with gas and sprayed into the slag. The entire selective enrichment link is completed within 10-30 minutes (the larger the volume of the slag tank, the longer the time). After the completion of selective enrichment, it enters into selective growth. The purpose of growing up is to make the CaTiO ₃ solid phase precipitated in the slag grow up and coarsen into larger grains as much as possible, so as to create conditions for the subsequent selective separation link. Because when the grain size is too small (<40 μm), the cost of grinding will increase greatly, so the lower limit of the grain size of the perovskite phase CaTiO ₃ is determined to be 50 μm. Of course, the larger the grain size, the better the separation. The technological method of realizing growing up is to control the temperature range during cooling between 1500-1200°C. When the temperature is lower than 1200°C, the growth rate is too low and has no practical significance. In principle, the slower the cooling rate, the more conducive to growth, but it is quite difficult to achieve a cooling rate lower than 0.5°C/min on an industrial scale. In order to ensure the cooling rate in the range of 0.5-5°C/min, the slag tank needs to be covered, and the side wall needs to be filled with insulation materials for heat preservation. When the cooling rate is greater than 5°C/min, it is not conducive to the growth of CaTiO ₃ phase. In this embodiment, the cooling rate is selected to be 0.5° C./min, and the holding time lasts for about 10 hours. In order to improve the morphology of CaTiO ₃ precipitated phase. It is beneficial to mineral separation, and additives need to be added, and several additives listed are effective. The amount added is 1-3%. The method of adding 1% Cr ₂ O ₃ in this embodiment is to add it when adjusting the composition of slag. The selective separation link is to pour out the slag from the slag tank, crush and grind it, and then separate it by gravity separation. The slag selectivity test shows that the perovskite particles are nearly evenly distributed in each particle size. Re-election separation equipment, the selection principle process is shown in Figure 5, and the selection results are shown in Table 4.

Table 4. Shaker gravity separation results product name Yield% TiO ₂ grade% Recovery rate% Concentrate 21.12 42.73 49.65 Middle mine 17.20 20.89 19.77 tailings 61.68 9.01 30.58 Raw ore 100.00 18.18 ^* 100.00

^* In the final product obtained by adding steel slag to reduce the grade of the raw ore, the TiO ₂ grade of the titanium-rich phase concentrate is ≥42.13%, and the TiO ₂ grade of the titanium-poor phase tailings is ≤9.01%.

Example 2, the composition of the original slag is shown in Table 5.

Table 5. Original composition of titanium-bearing blast furnace slag Element TiO ₂ SiO ₂ Al ₂ O ₃ CaO MgO TF % 24.44 23.60 14.51 27.45 7.53 6.88

Add the dust and lime whose composition is shown in Table 6.

Table 6. Composition of dust and lime Element TiO ₂ SiO ₂ Al ₂ O ₃ CuO MgO TF dust% 0.43 1.05 0.32 5.04 2.42 59.75 lime% 0 2.42 1.01 81.0 2.66 1.37

＝10^-6atm，在1500-1200℃温度范围内，冷却速度＝2.0℃min，添加剂CaF₂，添加量3％。凝渣的选择性分离方法同实施例1，选别结果如表7。Adjust the slag composition to achieve R=1.35, oxygen partial pressure

=10 ^-6 atm, in the temperature range of 1500-1200°C, the cooling rate = 2.0°C min, the additive CaF ₂ , the addition amount is 3%. The selective separation method of slag is the same as in Example 1, and the selection results are shown in Table 7.

Table 7. Shaker gravity separation results product name Yield% TiO ₂ grade % Recovery rate% Concentrate 23.77 38.24 38.33 Middle mine 36.36 25.28 38.76 tailings 39.87 10.63 22.91 Raw ore 100.00 23.60 100.00 The slag is re-selected and separated to obtain a separated titanium-rich phase with a _TiO2 grade of ≥38.24%, and the remaining titanium-poor phase has a _TiO2 grade of about 10%.

The titanium-rich phase obtained by applying the method of the invention can be used as furnace protection materials, titanium dioxide raw materials, etc.; the remaining titanium-poor tailings can be used as cement admixtures. The invention has the advantages of low investment, large processing capacity, low energy consumption, high benefit, easy industrialization, comprehensive utilization of resources, and elimination of environmental pollution.

Claims (6)

1. A method for separating titanium components from titanium-containing slag, characterized in that the method comprises three steps: a. Selective enrichment: add another one or several kinds of slag containing oxides CaO, SiO ₂ , Al ₂ O ₃ , MgO, FeO _x , MnO ₂ to the slag of the slag pot or slag trench containing titanium slag. A variety of metallurgical wastes - dust, tailings, waste slag, the addition amount is 5-15% of the total amount of titanium-containing slag, the basicity R of the slag is controlled between 1-2, and air or oxygen is injected into the slag to make it The oxygen partial pressure is maintained between 10-6-1atm; b. Selective growth: control the slag to cool within the temperature range of 1500°C-1200°C, the cooling rate is 0.5-5°C/min, and add 1-3% additives at the same time, requiring one or several compounds in the additives Cr ₂ O ₃ , MnO ₂ , CaF ₂ , P ₂ O ₅ , Si ₃ N ₄ , SiC, TiC, FeS, NiS, MnS, TiN; c. Selective separation: The perovskite phase in the cinder is separated by gravity or gravity separation combined with magnetic separation and flotation or gravity-flotation-electric separation. 2. The method for separating titanium components from titanium-containing slag as claimed in claim 1, characterized in that said selective enrichment process adds oxide-containing metallurgical waste to the titanium-containing slag, adding Method The crushed waste can be added to the slag ditch when the slag is discharged from the furnace, or added to the slag tank, or mixed with gas and injected into the slag. 3. The method for separating titanium components from titanium-containing slag as claimed in claim 1 or 2, characterized in that said selective enrichment process sprays oxygen or air into the molten slag, and the blowing time is 1 -10 minutes. 4. The method for separating titanium components from titanium-containing slag as claimed in claim 1, characterized in that the selective growth process determines the perovskite phase CaTiO ₃ . The lower limit of the crystal grain size is 50 μm. 5. The method for separating titanium components from titanium-containing slag as claimed in claim 1 or 4, characterized in that in the selective growth process, in order to ensure the cooling rate, the slag tank needs to be covered, and the side wall needs to be covered. Fill with insulation material to keep warm. 6. The method for separating titanium components from titanium-containing slag as claimed in claim 1, characterized in that said selective separation is to remove the clotted slag through selective enrichment and selective growth from the slag tank Pour out, crush and finely grind, and then separate by mineral processing.

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