RU2453618C2 - Method for processing oil containing leucoxene flotation concentrate for producing rutile - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method involves distillation of the oil fraction in an inert gas atmosphere, milling and reducing roasting of the mineral residue by petcoke. Then milling and sulphatisation of titanium cinder are performed with oleum and leaching of titanium-containing compounds with water.

EFFECT: increased chemical reactivity of the concentrate, elevated levels of anosovite phase in the concentrate, increasing increase cost-effectiveness activity of the process through utilisation of the oil fraction and absence of additional consumption of a reducing agent during roasting, reducing of environmental hazard due to decrease in temperature of recovery roasting and sulphatisation.

4 cl, 2 tbl, 1 ex

Description

The invention relates to the metallurgy of rare and dispersed metals, and in particular to methods for processing difficult-to-recover concentrates, in particular leukoxene flotation concentrates, which are a product of the enrichment of oil-bearing silicon-titanium ores used to produce artificial rutile - a raw material for the production of titanium by the chlorine method and pigment titanium dioxide.

The technology of obtaining artificial rutile from quartz-leukoxene concentrates composition,%: 56.3-59.6 TiO ₂ ; 28.7-31.5 SiO ₂ ; 0.7-1.1 Fe ₂ O ₃ ; 2.8-3.9 FeO; 2.4-4.5 Al ₂ O ₃ ; 0.2-0.3 CaO; 0.8-1 MgO; 0.05-0.15 MnO is relevant, since domestic and foreign markets demand high-quality mineral titanium concentrates (primarily rutile), which are necessary for the production of titanium pigments, metal titanium, titanium alloys and welding electrodes.

Known pyrometallurgical methods [1, 2] for the production of artificial rutile from ilmenite are not applicable in the case of leucoxene concentrate due to the thin intergrowth of rutile with quartz, reaching 2-3 microns: the predominant mass of leucoxene grains of greenish-gray color is covered on the outside with shirts or rims of fine-grained chlorite - quartz aggregate, sometimes containing siderite; inside leucoxene grains there are inclusions (several microns) of quartz or pyrite.

A known method of alkaline autoclave leaching of a flotation concentrate calcined at 900-1000 ° C to obtain titanium-rich products,%: 71-80 TiO ₂ , 12-2 SiO ₂ [3]. During the additional processing of the enriched product with hydrochloric acid and its subsequent refinement on a concentration table, it is possible to increase the TiO ₂ content in it to 80-85%.

The disadvantages of this method are: the need for additional operations (acid leaching); significant consumption of alkaline reagent (alkali, soda) and large volumes of alkaline solutions (5-6 m ³ per 1 t of TiO ₃ ) with a high content of SiO ₂ (~ 110 g / dm ³ ), which does not allow to utilize these solutions (for example, by precipitation of CaSiO ₃ ) with the regeneration of the alkaline reagent used.

A known method of producing pigment titanium dioxide from leukoxene concentrates composition,%: 45-50 TiO ₃ ; 40-45 SiO ₂ ; 1.5-3 Fe _(total) by sulfuric acid technology, including reducing roasting at a temperature of 1200-1350 ° C for 20-150 min, grinding the calcined concentrate to a particle size of 0.075 mm, mixing with concentrated sulfuric acid, heating to 200 ° C and exposure at this temperature for 1.5 hours, cooling and leaching with water [4].

The disadvantages of this method include a large energy intensity, the environmental hazard of the high-temperature sulfatization process, the use of sophisticated technological equipment.

The closest to the claimed invention in technical essence and the achieved result is a method of processing oil-containing leukoxene concentrates obtained by enrichment of silicon-titanium ores of the Yarega deposit, including roasting of the floc concentrate in the presence of additives, cooling, grinding and enrichment by separating the grains of titanium oxide from silicates by physicochemical and / or mechanical methods [5]. Before firing, the oil-titanium leukoxene flotation concentrate is mixed with fuel sorption-active additives for impregnation with oil from the flotation concentrate. The firing is carried out by filtration combustion in a super-adiabatic heating mode in a shaft type reactor. Reactive solid modifying additives in the form of refractory materials are used as inert additives. The firing temperature in the combustion zone is maintained within 900-1300 ° C by controlling the mass fractions of the combustible and non-combustible materials and oxygen fed into the reactor supplied with the oxidizing gas. The technical result is to increase the chemical activity (explosiveness) of the concentrate, increase the content of the rutile phase in the concentrate, increase the profitability of the process by obtaining and using product gas to generate heat, electricity and for own technological needs. The method adopted for the prototype.

The following features coincide with the essential features of the invention: a method for processing titanium-containing concentrates to produce rutile, which includes reducing calcining of leucoxene concentrates, further cooling, grinding and sulfating of calcined concentrates upon heating, followed by leaching of sulfated cinder with water.

The disadvantages of this method are: irreversible loss of oil from an oily concentrate due to its deep burning; use for firing sophisticated technological equipment - a shaft type reactor with various temperature zones (heating, drying, pyrolysis, combustion, cooling); high energy intensity of the process.

The technical problem solved by the claimed invention is the processing of flotation quartz-leukoxene concentrates in order to obtain artificial rutile by extracting oil from an oil-containing titanium-silicon leukoxene flotoconcentrate, preparing for more efficient further enrichment of titanium-silicon concentrate due to the implementation of favorable physicochemical, mechanical and phase transformations inside the concentrate under optimal conditions of the processes of its reducing roasting, sulfatization and leaching.

The technical results of the claimed invention are:

- increase the profitability of the processing of flotation concentrates due to the allocation of oil in the form of a separate fraction;

- an increase in chemical activity (explosiveness) due to an increase in the content of the anosovite phase in quartz-leukoxene concentrates;

- lack of additional reducing agent consumption during firing;

- reduction of environmental hazard due to a decrease in the temperature of firing of the mineral residue and sulfatization of the titanium-containing cinder.

The technical result is achieved by the fact that the method of processing oil titanium leucoxene concentrates to obtain rutile involves sublimation of the oil fraction in an inert gas (argon) at a temperature of 800 ° C and cooling of titanium-silicon concentrates, as well as further grinding and reduction calcination of titanium-silicon concentrates at a temperature 1100-1150 ° С for 50-60 min, cooling, grinding and sulfatization of the cinder with oleum at a temperature of 150 ° C for 50-60 minutes, cooling of the sulfated cinder and leaching of sulfate titania with water at a temperature of 90-95 ° C for 50-60 min.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by features that are identical (identical) to all the essential features of the invention. The definition from the list of identified analogues of the prototype as the closest in the totality of the features of the analogue allowed us to establish a set of essential distinguishing features set forth in the claims as seen by the applicant technical result set forth in the claims. Therefore, the claimed invention meets the criterion of "novelty."

The inventive method of processing oil titanium leukoxene flotation concentrate to obtain rutile meets all the criteria of patentability.

The invention proposed for patent protection has an inventive step, because its essence for a specialist in the metallurgy of rare and trace metals does not explicitly follow from the prior art, i.e. no solutions have been identified that have signs that match the distinguishing features of the proposed method, and therefore, the fame of the distinctive features to the technical result indicated by the applicant cannot be confirmed.

The claimed invention is industrially applicable, because it can be used in production for its intended purpose, i.e. for processing titanium-containing concentrates. Not a single feature taken separately, nor the totality of the features of the method contradicts the possibility of their application in industry and does not prevent the achievement of the technical result perceived by the applicant.

An example of the method

The oil-containing leukoxene flotation concentrate was processed to obtain rutile, coming from the processing plant, in the form of pulp of the following composition, wt.%: 46.6 - leukoxene concentrate (mineral phase); 21.7 - oil (organic phase); 31.7 - water.

For the normal course of the oil sublimation process, it is necessary that the humidity of the flotation concentrate (68.2% - mineral and 31.8% - organic phases) does not exceed 1.5-2 wt.%, For which the pulp was defended, water was decanted, and the solid phase was dried to the desired humidity level.

Sublimation of oil (100%) was carried out in a metal reactor heated by gas burner devices at a temperature of 800 ° C for 50-60 minutes in an inert gas atmosphere (argon). The condensation of gaseous sublimation products was carried out using a refrigerator at a temperature of 20 ° C. As a result, condensed oil fractions (81.5%), neftekoks (15.1%) in the composition of the mineral residue and irreversible losses — the non-condensed gaseous component (3.4%) were obtained.

Mineral titanium-containing residue composition,%: 39.6 TiO ₂ (24 Ti); 41.1 SiO ₂ ; 1.75 Fe _total ; S _total 1.1; C _total 5; With a _{TV of} 4.8, it was ground in a rod mill with peripheral discharge to a particle size of -2 mm.

The amount of petroleum coke (4.8%) in the composition of the mineral titanium-containing residue after distillation of oil is sufficient to carry out reduction firing in an inclined rotary kiln, which allows the higher oxide - rutile (TiO ₂ ) to be decomposed to a more soluble lower oxide - anosovite (Ti ₃ O ₅ ) whose lattice, being more defective, is also more reactive, according to the total reactions:

6TiO ₂ + C = 2Ti ₃ O ₅ + CO ₂ ;

CO ₂ + C = 2CO;

3TiO ₂ + CO = Ti ₃ O ₅ + CO ₂ .

Solid-phase conversion of higher titanium oxides to lower ones (degree of decomposition of rutile γ = 94.5-99%) occurs in the inventive method at lower temperatures (t = 1100-1150 ° C) and in a shorter period of time (τ = 50-60 min) , compared with the prototype (t = 1200-1350 ° C; τ = 20-150 min) (table 1).

Table 1 Rutile Recovery Process Indicators Firing temperature, ° С The content of TiO ₂ / Degree of decomposition of TiO ₂ ,% Flotation concentrate (τ = 0.85-1 h) Charge (τ = 2-2.5 h) twenty 40.3 / 0 40/0 900 4.7 / 88.3 8.8 / 78 1000 2.5 / 93.8 5.4 / 86.5 1100 0,4 / 99 2.7 / 93.3 1200 0.5 / 98.8 1.4 / 96.5 1300 0.6 / 98.5 1.45 / 96.4

This result is achieved due to the presence on the surface of the mineral titanium-containing residue of chemisorbed petcoke from the primary oil fraction, selectively adsorbed on the surface of the leucoxene concentrate and reducing its chemical activity during flotation processing of the initial quartz-leucoxene ore composition,%: 90-93 mineral phase (sandstone), in including 16.3 leukoxen; 8.4 siderite; 75.3 quartz; 7-10 organic phase (oil).

The obtained titanium-containing cinder was ground in a rod mill with peripheral discharge to a fineness of 0.1 mm, mixed with oleum (SO ₃ ≥19%) at T: W = 1: (1-10), the pulp was heated to 150 ° C and kept in for 50-60 minutes in a sealed heat-insulated apparatus equipped with a mixing device, heating systems and gas utilization (SO ₂ , SO ₃ , water vapor) (table 2).

For sulfatization of anosovite ([Ti ₃ O ₅ ] _m · [SO ₃ ] _n ), reduced from rutile, in the present method used oleum (GOST 2184-77) instead of the concentrated sulfuric acid used in the prototype.

The presence of 19-24% of free sulfuric anhydride (SO ₃ ) in the oleum allowed to reduce the temperature and duration of the anosovite sulfatization process in the present method (t = 150 ° C; τ = 50-60 min) compared with the prototype (t = 180-200 ° C; τ = 90-120 min).

In the chemical treatment of a titanium-containing cinder, the structure of silicates is additionally destroyed and their individual fine fraction is formed, which helps to clean the aggregates from anosovite.

After cooling the pulp, titanium sulfate is leached with water at T: W = 1: (1-10) for 50-60 minutes at a temperature of 90-95 ° С (Table 2).

table 2 The degree of sulfation of anasovite (α) with oleum and sulfuric acid and the leaching of titanium sulfate (β) with water The ratio of T: W α / β,% Oleum (t _c = 150 ° C, τ _s = 1 h) Sulfuric acid (t _c = 200 ° С, τ _c = 2 h) 1: 1 99 / 54.5 97.5 / 53.7 1: 2 99 / 69.3 97.5 / 68.3 1: 3 99 / 81.2 97.5 / 80 1: 4 99 / 91.1 97.5 / 89.7 1: 5 99 / 97.8 97.5 / 96.3 1:10 99/98 97.5 / 96.5

The degree of extraction of titanium is not less than,%: 99 - in solution; 98 - from leukoxene flotation concentrate.

Based on the studies, it can be concluded that it is the totality of the claimed features that ensures the achievement of a technical result, namely, the most effective decomposition of the oil-containing leucoxene concentrate to obtain rutile with a high extraction of titanium sulfate into solution.

Thus, the claimed method allows to solve the most important technical problems in the processing of oily flotation concentrates to obtain rutile:

- increase the profitability of the process by separating oil as a separate fraction, suitable for further redistribution at refineries;

- to increase the chemical activity (openability) due to the transfer of rutile to the anosovite phase in quartz-leukoxene concentrates during reductive firing;

- abandon the additional consumption of reducing agent during firing;

- in the process of sulfatization to further destroy the structure of silicates and to clean the grains of anosovite from intergrowths;

- reduce the temperature, duration and, accordingly, the degree of environmental hazard during sulfatization of a titanium-containing cinder.

Literature

1. Elger G.W., Kirby D.E. and Rhoads S.C. Producing Synthetic Rudle from Ilmenite by Pyrometallurgy Pilot Plan Stadies and economic Evaluadon / Rept. Invest Bur. Mines U.S. Dep. Inter., 1976.

2. Titanium / Edited by V.A. Garmaty. M .: Metallurgy, 1983. P.559.

3. Fedorova M.N. Chemical finishing of titanium concentrate by autoclave leaching of silicic acid. In the book. Titanium and its alloys, c. 9. M .: Publishing House of the Academy of Sciences of the USSR, 1963. P.36-41.

4. Pat. 2001138 (Russian Federation). A method for processing leukoxene concentrate / L.F. Alekseev, A.M. Berseneva, N.A. Watolin and others. 1991.

5. Pat. 2334799 (Russian Federation). A method for processing oil titanium leukoxene concentrates / A.V. Aladyin, V.V. Pastikhin, G.V. Ardasov and others. 2007.

Claims (4)

1. A method of processing an oil-containing leukoxene flotation concentrate to produce rutile, including reductive calcination, grinding, sulfatization, decomposition and leaching, characterized in that the oil fraction is preliminarily distilled off in an inert gas atmosphere at a temperature of 800 ° C for 50-60 minutes, with sulfatization used oleum containing 19-24% of free sulfuric anhydride (SO ₃ ) at a temperature of 150 ° C for 50-60 minutes 2. The method according to claim 1, characterized in that as a reducing agent during firing, petroleum coke is used after distillation of the oil fraction. 3. The method according to claim 1, characterized in that the regenerative firing is carried out at a temperature of 1100-1150 ° C for 50-60 minutes 4. The method according to claim 1, characterized in that the leaching is carried out with water at T: W = 1: 5 for 50-60 minutes at a temperature of 90-95 ° C.