RU2410449C1 - Method of processing titanium-magnetite concentrate - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: invention relates to method of processing titanium-magnetite concentrate. Proposed method comprises mixing proposed concentrate with carbon reducing agent, heating, and reducing metal iron from iron oxides of titanium-magnetite concentrate to produce reduced calcine containing metal and oxide phases on the bases of iron and titanium dioxide. Note here that a portion of titanium-magnetite concentrate (TMC) making 60.5-74.7% is subjected to mixing with carbon reducing agent. Then, reducing sulphuric-acid leaching of iron from obtained calcine is performed to produce leaching residue, as well as calcination of leaching residue to produce titanium oxide concentrate (TOC). Obtained TOC is mixed with second portion of TMC making 36.7-22.0%, and aluminium powder (AP) at the following ratio of components in wt % by wt: TMC - 40-55, TOC - 20-30, AP - 25-30. Then, obtained mix material is loaded into melting furnace. Ignition mix material made up of one third of TMC making 2.7-3.3%, and AL, is poured onto melting furnace surface. Said TMC and AL are mixed at the following ratio, wt %: TMC - 65-75, AP - 25-35. Ignition charge surface is heated to spontaneous aluminothermic process with subsequent melting of mix material and separation into ferrous titanium and slag to be discharged and crystallised. ^ EFFECT: higher efficiency of proposed process due to reduced costs. ^ 2 tbl, 1 ex

Description

The invention relates to the field of metallurgy and, in particular, to the integrated processing of titanomagnetite concentrates and can be used to obtain iron-titanium alloys enriched in titanium content from ilmenite, rutile and other oxide titanium concentrates.

A known method of processing titanomagnetite concentrate which is a product of ore dressing [Deposits, metallurgy, chemical technology. Reznichenko V.A., Shabalin L.I. Titanomagnetites. - M .: Nauka, 1986, p.118-136]. The method includes mixing a titanomagnetite concentrate with a carbon reducing agent (coke), loading the resulting mixture (charge) into a heating furnace, heating the charge and reducing oxides of ferrous and ferric iron at this temperature to obtain a reduced calcine concentrate containing metal and oxide phases based on iron and titanium dioxide. After that, the cinder is melted, followed by separate discharge, crystallization and cooling of cast iron and titanium slag for the subsequent production of vanadium alloyed alloys and pigment titanium dioxide, respectively. When titanium slag is processed, a white pigment titanium dioxide powder is obtained. The method is characterized by a large number of technological stages, high specific technological costs for producing cast iron, titanium slag and pigment titanium dioxide, a significant cost, a relatively low content of titanium dioxide in titanium slag and its relatively low extraction from them into pigment titanium dioxide.

The closest one selected for the prototype is a method for processing titanomagnetite concentrate [Technology for refinement and hydrometallurgical processing of Khibiny high-titanium titanomagnetite. Ore dressing. - M.: Ore and Metals, 2004, No. 1, pp. 25-27, Popov I.O., Makarov A.M., Rakaev A.I., Bryantsev A.Ya., Brylyakov Yu.V.]. The method includes mixing a titanomagnetite concentrate with a carbon reducing agent (coke), loading the resulting mixture of the mixture into a heating furnace, heating the mixture to a temperature of 1100-1300 ° C and reducing the ferrous and ferric iron oxides at this temperature to obtain a reduced calcine concentrate containing metal and oxide phases, respectively, based on iron and titanium dioxide, cooling and grinding the cinder, oxidative sulfuric acid leaching (with air supply to the solutions) of iron from the cinder to both with sulfuric acid solution of baths of electroextraction of iron, obtaining by electroextraction of electrolyte iron from cinder leach solutions, calcination of the coke leach solid residue in a heating furnace with simultaneous oxidation of the residual carbon coke contained in it and with the production of enriched titanium oxide concentrate containing more than 70% titanium dioxide, cooling titanium concentrate. The next stage of the processing of titanomagnetite concentrate includes grinding the titanium oxide concentrate, sulfatizing the titanium oxide powder in a heated solution of strong sulfuric acid, producing sulfate titanium oxide concentrate, leaching the melt with water and converting it into sulfate solutions of titanium and iron impurities, and obtaining insoluble soluble leach residue based on the impurity part of an oxide titanium concentrate, isolation from a sulfate solution of titanium by hydrolysis in tv a variety of metatitanic acid hydrolysis sediments, calcining the hydrolysis precipitate at a temperature of ~ 900-950 ° C in a heating furnace to separate crystallization water, sulfuric acid vapor and sulfur dioxide into the gas phase, cooling and grinding the calcination calcine to obtain a white pigment titanium dioxide powder .

The disadvantage is the relatively high unit costs and a significant number of technological stages of obtaining pigment titanium dioxide, which leads to low processing efficiency.

The objective is to increase the processing efficiency of titanomagnetite concentrate by reducing technological costs, the number of technology redistributions and obtaining ferro-titanium of high chemical composition on its iron-titanium oxide base.

A method for processing a titanomagnetite concentrate is proposed, including mixing it with a carbon reducing agent, heating and reducing metallic iron from iron oxides of a titanomagnetite concentrate to produce a reduced cinder containing metal and oxide phases based on iron and titanium dioxide, oxidative sulfuric acid leaching of iron from the obtained cinder to obtain a residue leaching, calcining the obtained leach residue to obtain a titanium oxide concentrate. A part of the titanomagnetite concentrate (TMK), comprising 60.5% -74.7%, and from which the titanium oxide concentrate (TOC) is obtained, is mixed with a carbon reducing agent. The oxide concentrate is mixed with the second part of titanomagnetite concentrate (TMK), component 36.7% -22%, and aluminum powder (PA) with the following ratios of components, wt.%: TMK - 40-55, TOK - 20:30, PA - 25- thirty. The resulting mixture is loaded into a smelting furnace, the ignition mixture consisting of the third part of titanomagnetite concentrate (TMK), comprising 2.7% -3.3% and aluminum powder, which are mixed in the following ratios of components, wt. %: TMK - 65-75, PA - 25-35. The surface of the ignition mixture is heated until the spontaneous aluminothermic process begins, followed by melting of the charge and separation into ferrotitanium and slag, which are drained and crystallized.

In the proposed method, the separation of TMC into three parts and their subsequent use in the process, preliminary isolation of TC from a portion of TMC and the use of PA make it possible to obtain high-quality ferrotitanium (with a titanium content of more than 20 wt.%) From iron and titanium oxides of TMC and TC ( alloy with iron to remove) in one technological operation. This allows, in comparison with the prototype, by reducing the multi-stage processing of TMK to reduce the cost of extracting titanium into commercial products, as well as to increase the efficiency of the process of processing the current using one main technological operation during its aluminothermic melting together with TMK on ferrotitanium, and in addition, significantly reduce investment. Thus, the combination of distinctive features is necessary and sufficient to solve the problem.

The consumption of one part of 60.5% -74.7% of TMK to obtain the maximum 20 and 30 units. the mass of TOK in the charge and the second part of TMK - 36.7% -22% is determined based on experimental data and the balance of titanium dioxide, according to the formula: TMK1 = M (TOK) × С _TOK (TiO ₂ ) / С _ТМК (TiO ₂ ), where M (CURRENT) - the mass of CURRENT in the charge of 20 and 30 units. mass, C _TOK (TiO ₂ ) and C _TMK (TiO ₂ ) - the content of titanium dioxide in TOK and TMK. When using 2.7-3.3% TMC as the ignition mixture, based on the weight of the initial TMK with the ratio of TMK and PA, the heat released after it is ignited is sufficient for the initial development of the aluminothermic process in the melted batch to produce melts or cakes, respectively, due to the different composition of the batch. When less than 2.7% of TMC is used as the ignition mixture, the heat generated after its ignition is not enough for the development of the aluminothermic process in the blends and almost the entire mass of the charge in the crucible of the furnace remains loose. When using more than 3.3% TMC as the ignition mixture, the generated heat is sufficient for the initial development of the aluminothermic process, however, this leads to a decrease in the titanium content in the resulting ferrotitanium due to its dilution with a melt of poor ferrotitanium. When the PA content is less than 25 and more than 30 wt.%, Respectively, due to a deficiency or excess of a reducing agent (aluminum) for the reduction of basic charge oxides (Fe ₂ O ₃ , FeO, TiO ₂ , V ₂ O ₅ , MnO and SiO ₂ ) contained in mixtures of TMK and TOK, the specific heat of the aluminothermic reaction (per unit mass of the charge), or the exothermicity of the process, decreases. With a decrease in the exothermicity of the process of heat generated from the exothermic reactions of the aluminothermic process, it becomes insufficient to completely melt the reaction products and a poor-quality intermediate product of smelting in the form of cake is obtained. When the current content in the charge is less than 20 wt.% And TMK more than 55 wt.%, The resulting iron-titanium alloy contains less than 20 wt.% Titanium and therefore does not comply with GOST branded ferrotitanium. When the current content in the charge is more than 30 wt.%, The exothermicity of the process is not enough to melt the melting products. When the content in the charge of TOK is more than 30 wt.% And TMK is less than 40 wt.%, The heat of exothermic reactions for melting and separation of aluminothermic smelting products is insufficient due to an increase in the ratio of mass contents of oxides of TiO ₂ , :( Fe ₂ O ₃ + FeO ) and lower thermal effect of the aluminothermic reduction reaction of titanium oxides to the metal, in comparison with iron oxides. In addition, the exothermicity of the TC is lower than that of TMC due to the higher content of impurity oxides in the TC, such as calcium, sodium, potassium, aluminum, and magnesium, which are not reduced during the production of ferrotitanium and dissolve in the slag. The igniter mixture with the ratio TMK: PA (65-75) :( 25-35) in it has the highest exotherm. It is this ratio of components that provides a more complete chemical reaction with the highest heat release (Table 2)

The method is implemented as follows. From one part (1 part) of a titanomagnetite concentrate, titanium oxide concentrate is preliminarily isolated by a known method. To do this, titanomagnetite concentrate is mixed with coke and the charge is loaded into a heating furnace and heated in a furnace to a reduction temperature of iron oxides of 1100-1300 ° C. At this temperature, coke is reduced by iron from its oxides to a metal state, after which it is cooled and crushed 85 wt.%, Cinder to a grain size (-0.3 + 0.07 mm). The cinder powder is loaded into the acid-resistant capacity of the reactor filled with sulfuric acid solution equipped with devices for heating, mixing and aeration of solutions with air. Leaching of iron from cinder powder is carried out. In the reactor at a temperature of 35-55 ° C, the content of free sulfuric acid in an aqueous solution is 15-100 g / l, the initial ratio of cinder mass to solution (t: g) = 1: (5-15), the number of revolutions of the mixer is 60 -180 rpm, air aeration of the solution 0.5-1.5 m ^{3 of} air per m ^{3 of} solution per minute. Sulfate solutions of iron are separated from the solid titanium-containing leach residue. After iron leaching, the pulp from the reactor is directed to a filter and the leaching residue containing titanium dioxide is filtered. It is loaded into a calcining furnace and heated in it to a decomposition temperature at 600-900 ° C of the impurities of iron crystalline hydrates contained in the residue and complete removal of moisture from them into the gas phase at the same time, at the same temperature, oxidation by atmospheric oxygen and transfer to the gas phase impurity carbon contained in the residue. The calcined residue, which is a titanium oxide concentrate based on titanium dioxide, is cooled and ground to 0.05-0.1 mm - 95% for subsequent processing. Next, another (2 part) titanomagnetite concentrate (TMK) is mixed with titanium oxide concentrate (TOC) preliminarily extracted from TMK and with aluminum powder (PA) (Table 1).

The charge is loaded into the melting furnace bath lined with refractory material, for example, the ignition mixture is centrally loaded onto the charge layer, the surface of the ignition mixture is heated until the aluminum-thermal process begins in it using an electric spark created by a special device, reducing aluminum with iron, titanium, and impurity metal oxides - vanadium, manganese, silicon with simultaneous melting and density separation of the resulting melting products: the lower, which is a melt of ferrotitanium and the upper, is a melt varnish. Ferrotitanium and slag melts are drained from the furnace, crystallized, mechanically separated from each other (by chipping), and high-quality ferrotitanium is obtained. Sulfate solutions of iron are sent for further processing by known methods.

Example

For testing, we used a typical Khibiny titanomagnetite concentrate (TMK) (product of complex processing of apatite-nepheline ores of the Kola Peninsula) composition, wt.%: 15.9 TiO ₂ , 40.8 FeO, 36.2 Fe ₂ O ₃ , 1.7 SiO ₂ , 1.5 CaO, 0.4 MgO, 0.7 Al ₂ O ₃ , 0.8 Na ₂ O, 0.3 K ₂ O, 0.3 V ₂ O ₅ , 1.2 MnO ₂ , 0.2 P ₂ O ₅ with particle size -1 + 0.2 mm - 24.1%, -0.2 + 0.071 mm - 40.6 %, -0.071 mm - 35.3% and previously isolated from it (according to the technology described in [Technology for lapping and hydrometallurgical processing of Khibiny high-titanium titanomagnetite. Ore dressing. - M. Ore and Metals, 2004, No. 1, pp. 25-27, Popov I.O. ., Makarov AM, Rakayev A.I., Bryantsev A.Ya., Brylyakov Yu.V.]) titanium oxide concentrate (TOC), wt.%: 72.1 TiO ₂ , 3.8 FeO, 7.5 SiO ₂ , 6.6 CaO, 3.4 Al ₂ O ₃ , 1.7 MgO, 3.2 Na ₂ O, 1.3 K ₂ O, 0.1 V ₂ O ₃ , 0.2 MnO, 0.1 P ₂ O ₅ . with fineness class -1 + 0.2 mm - 17.1%, -0.2 + 0.071 mm - 67.2%, -0.071 mm - 15.7%; the moisture content of TMK and TOK was 0.03 and 0.01 wt.%, respectively. As a reducing agent for iron and titanium oxides, aluminum powder of the grade PA-4 was used, fractions (-0.3 + 0.1) mm - 85 wt.% And (-0.1) mm - 15 wt.%

The conditions for the preliminary isolation of the TOK were as follows: mixing of TMK - 76 wt.% And pitch coke - 24 wt.%, Loading the charge into the chamber of the heating furnace in graphite chamotte crucibles (0.5 kg of the charge in the crucible each), heating the charge in the furnace and reducing carbon oxide coke TMK iron at Т = 1250-1260 ° С for 3.5 hours to obtain metallic iron phases in the cinder. Unloading cinder from the furnace and cooling it (to T = 16-18 ° C), grinding and averaging cinder in a ball mill to obtain a crushed cinder with a fineness class (- 0.3 + 0.1) mm - 68.3 wt.%, (-0.1 mm) - 31.7 wt.%, Leaching of iron from the crushed cinder in an aqueous solution of sulfuric acid (with an initial content of H ₂ SO ₄ in an aqueous solution of 50 g / l and the ratio of cinder mass to solution (t: W) = 1: 15, with a constant the temperature of the solution is 50-52 ° C. Then the residue of the cinder leaching was separated from the solution by filtration and calcined at a temperature of 1100 ° C for 2.5 hours in graphite chamotte crucible. The product obtained during calcination - TOK, after cooling, was crushed in a ball mill.

Experimental melting mixtures consisting of TMK, TOK and AP were carried out in open refractory (alundum) crucibles with an internal volume of 1 dm ³ in air. Each charge (0.9 kg) was loaded into a separate crucible. An ignition mixture (0.05-0.06 kg) consisting of (Table 2) of a mixture of TMK and aluminum powder in the ratio of TMK - 65-75 wt.% And PA - 25-30 wt.% Providing more than high temperatures of its melting. (table 1, table 2). A nichrome wire (2 mm in diameter and 20 mm long) was connected to the surface of the ignition mixture, connected via an autotransformer to an alternating current network, and heated until an aluminothermic reduction of iron and titanium oxides occurred in the mixture. Further, this process spontaneously spread already due to the heat of exothermic reactions of reduction of iron and titanium oxides to the entire ignition mixture and the entire charge volume. After 1.5-2 minutes from the beginning of the aluminothermic process, the melting products in the crucible completely melted and exfoliated, forming two layers: the lower one is the ferrotitanium melt and the upper one is the slag melt. In this case, the exothermic reactions in the crucible were completed. The resulting melts were then crystallized and cooled in a crucible to a temperature of 18-20 ° C by natural heat transfer from the melts. Then, solid melting products were discharged from the crucible, separated into ferrotitanium and slag by chipping along their interface, separately weighed and the chemical composition of ferrotitanium and slag was determined according to the standard method.

The composition of the ignition mixture in the experiments of table 1 was as follows: TMK: AP 65:35 wt.% In experiments No. 2-No. 3, TMK: AP 70:30 wt.% In experiments No. 1, No. 4-No. 6, TMK: AP 65:35 wt.% In experiments No. 7-No. 12. The consumption of the ignition mixture in experiments No. 2-No. 6 was 0.05 kg for melting, and in experiments No. 7-No. 12 - 0.06 kg for melting. The composition of the iron-titanium alloy formed during the melting of the ignition mixture was determined in experiment No. 1 (table 1).

Table 1 Experience Number The ratio of the parts of TMK in processing: TMK The ratio of components in the charge: TMK: CURRENT: PA wt.% The titanium content in ferrotitanium, wt.% With The aluminum content in ferrotitanium, wt.% Smelting product rating ¹⁾ one 2 3 wt.% one.. 97 0 3 70: 0: 30 8.6 8.9 melt 2. 51 46 3 60:15:25 14.3 6.9 melt 3. 67 thirty 3 50:25:25 25.3 7.7 melt four. 70 26 four 47:27:26 26.9 8.0 melt 5. 75 21 four 40:30:30 29.4 8.4 melt 6. 77 19 four 45:36:24 - - spec 7. 63 34 3 50:20:30 22.1 9.9 melt 8. 72 24 four 50:30:20 - - spec 9. 61 36 3 55:20:25 20.2 7.9 melt 10; 68 29th 3 45:24:31 19.7 12.6 melt eleven. 71 25 four 40:25:35 - - spec 12. 64 33 3 55:23:24 17.9 7.4 melt

table 2 The composition of the ignition mixture, wt.% Slag melt temperature, ° С Example TMK PA one 60 40 1720 2 65 35 1820 3 70 thirty 1860 four 75 25 1840 5 80 twenty 1700

As follows from Table 1, the experimental melts of the blends were characterized either by the production of melts of ferrotitanium and slag, or by the formation of cakes. The latter were obtained due to the lack of heat from exothermic reactions of aluminum reduction of the oxides (mainly iron and titanium) of TMK and TOK. Moreover, in all experiments, the use of the hardening mixture of TMK and PA ensured the initial development of the aluminothermic process in the charge mass. In experiments No. 3-5, 7, 9, ferrotitanium was obtained with a content, wt.%: (20.2-29.4) - Ti, (7.2-9.2) - Al, (2-3) - Si, (0.02-0.03) С, (0.06-0.08) - P, (0.02-0.03) - S, (0.2-0.4) - V, Mn, less than 0.05% of the total (Mo, Sn, Cu, Zr, Cr), the rest is iron, which in terms of titanium and impurities refers to high-quality or branded ferrotitanium (grade FTi 25 according to GOST 4761-91). The average extraction of titanium from titanium oxides TMK and TOK into ferrotitanium amounted to 72.4%.

The method allows to obtain ferrotitanium in one technological operation. This allows you to increase the efficiency of the processing process and significantly reduce investment.

Claims (1)

A method of processing a titanomagnetite concentrate, including mixing it with a carbon reducing agent, heating and recovering metallic iron from iron oxides of a titanomagnetite concentrate to obtain a reduced cinder containing metal and oxide phases based on iron and titanium dioxide, oxidative sulfuric acid leaching of iron from the cinder obtained to obtain a leach residue , calcining the obtained leach residue to obtain a titanium oxide concentrate, characterized I mean that a part of titanomagnetite concentrate (TMK), comprising 60.5-74.7%, is subjected to mixing with a carbon reducing agent, and from which a titanium oxide concentrate (TOC) is obtained, which is mixed with the second part of titanomagnetite concentrate (TMK), component 36 , 7-22%, and aluminum powder (PA) in the following ratio of components, wt.%: TMK 40-55, TOK 20-30, PA 25-30, load the resulting mixture into the melting furnace, onto the surface of which the ignition mixture is filled, consisting of the third part of titanomagnetite concentrate (TMK), 2.7-3.3%, and aluminum powder (PA), which are mixed at the following ratios of components, wt.%: TMK 65-75, PA 25-35, heat the surface of the ignition mixture until a spontaneous aluminothermic process begins, followed by melting charge and separation into ferrotitanium and slag, which are drained and crystallized.