RU2757774C2 - Method for leaching tungsten from tin raw material smelting slag and an apparatus for its implementation - Google Patents

Abstract

FIELD: non-ferrous metallurgy.

SUBSTANCE: invention relates to non-ferrous metallurgy and is intended for use in leaching processes, for example, tin concentrates and slags with solutions. Leaching of tungsten from slag of smelting tin raw materials is carried out in an aqueous solution containing, g/l: soda 10-20, sodium hydroxide 5-10, sodium chloride 10-20, which is heated to 70-90°C, fed to the slag in the form of granules with a grain size of 0.5-4 mm and affected by vibration oscillations with a frequency of 30-50 Hz and an amplitude of 0.5-4 mm, directed at an angle of 30-40°. In this case, a moving vibrating boiling layer of suspension is formed, which is affected by a spark discharge with a potential of 10-30 kV with air supply through the electrode into the discharge zone with the formation of a solution of sodium tungstate. Leaching is carried out in an apparatus containing a tray with a vibrator, a loading hopper and a device for feeding and removing the solution. The tray with a vibrator is designed to provide directional oscillation of the tray at an angle of 30-40° to the horizon. In the middle part of the tray cover, at least one electrode is installed in the form of a steel tube in fluoroplastic insulation, connected via a capacitor to a high-voltage network, made with the possibility of supplying air through the electrode to the discharge zone.

EFFECT: proposed method and device make it possible to selectively extract tungsten into a solution in a continuous mode using a vibrating apparatus for subsequent isolation of tungsten acid.

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Description

The invention relates to nonferrous metallurgy and is intended for use in the processes of water leaching, for example, slag smelting tin concentrates.

A known method of extracting tungsten from slag in an autoclave at a temperature of 225 ° C with a soda solution with a soda consumption of 80% of the slag [1. Bulletin of the Tomsk Polytechnic University, 2013, v. 322, no. 3, p. 62-64].

The disadvantage of this method is that the extraction of tungsten into the solution is low and amounts to 41-52%.

There is a known method of intensifying the processing of materials by leaching, taken as a prototype, which consists in the fact that before leaching the material is exposed to an electromagnetic pulse [2. Patent No. 2139142 Mkl. В03В 7/00].

The disadvantage of this method is in its frequency of exposure.

The apparatus [3. Auth. St. No. 367736; Mkl. C 22b 3/02] for leaching concentrates and slags, for example, tin, including a tray with a vibrator, a feed hopper and devices for feeding and discharging solution, characterized in that, in order to intensify the leaching process, the bottom of the tray is made with holes in which magnetostrictive transducers flush with the inner surface of the bottom.

The apparatus, adopted as a prototype, in relation to tin slag has insufficient efficiency.

This is due to the fact that the apparatus is designed to intensify the leaching of an acid-soluble impurity and therefore its stirring effect promotes dissolution. To extract insoluble tungsten from the slag, it must be ionized or at an elevated temperature above 180 ° C.

The technical problem is the leaching of tungsten from the slag of smelting tin raw materials in a soda-alkaline solution in a continuous mode.

The essence of the method lies in the fact that the process of leaching tungsten from slags is carried out in an aqueous solution heated to 70-90 ° C, containing, g / l: soda - 10-20, sodium hydroxide - 5-10, sodium chloride - 10-20, which act on the slag in the form of granules with a grain size of 0.5-4 mm. The suspension is exposed to vibrational vibrations with a frequency of 30-50 Hz and an amplitude of 0.5-4 mm, directed at an angle of 30-40 degrees with the formation of a moving vibrating layer of the suspension. The fluidized bed of the suspension is exposed to a spark discharge with a potential of 10-30 kV with the supply of air through the tubular electrode to the current discharge zone to increase the ionization of the suspension with the formation of a sodium tungstate solution.

The method is carried out in an apparatus containing a tray with a vibrator, a loading hopper and a device for supplying and discharging an aqueous solution, characterized in that the tray is equipped with a vibrator of directional vibrations of the tray at an angle of 30-40 degrees to the horizon, which ensures the movement of a slag suspension in an aqueous solution. In the middle part of the tray cover, at least one electrode is installed in the form of a steel tube in fluoroplastic insulation, connected through a capacitor to a high-voltage network. Air is supplied to the discharge zone through the electrode tube.

The positive effect is achieved by the interaction of these signs. Under the action of a given vibration frequency, the granular material (slag) in the solution is a boiling suspension moving up the chute under the action of a given amplitude of oblique vibrations at an acute angle. Soda-alkaline solution flows towards the moving layer of granular slag. Simultaneously, a spark discharge at a predetermined high voltage potential from the needle-shaped tubular electrode to the base of the tray is applied to the boiling suspension of slag grains in the electrolyte, with air supply through the electrode. With a short discharge pulse of the flowing current from the electrode needles to the bottom, energy is released by a narrow channel with local overheating of the material, which contributes to the dissolution of tungsten. This leads to a sharp increase in pressure and destruction of the surface of the slag grains. In addition, the spark discharge ionizes the oxygen in the supply air to form ozone, which oxidizes the iron that binds tungsten. Vibration vibrations not only move the material, but also create a vibrating layer that increases the effect of the spark discharge. An electrically conductive aqueous medium reduces the breakdown potential due to an increase in the electric field strength at the points of inhomogeneity of boiling particles, in contrast to the effect on a lying fixed layer. By adjusting the gap between the electrodes and the capacitor in the network, it is possible to provide a field strength with a repetition rate. The number of pulses varies depending on the conditions of the experiments. In addition, under the action of a current discharge in the electrolyte, additional ions OH ^- and peroxide compounds O ^{-3 are formed} , which oxidize Fe ⁺² iron in the compound FeWO ₄ to Fe ⁺³ , increasing the activity of ions (WO ₄ ) ^-2 .

The solution in the form of sodium tungstate flows down through the threshold from the tray. The composition of an aqueous solution containing NaCl provides the binding of oxidized Fe ⁺³ ions in FeCl ₃ , which hydrates, turning into a slime Fe (OH) ₂ Cl. In the initial slag, tungsten is bound not only in the FeWO ₄ compound, but partly tungsten is also bound with calcium, which is destroyed and calcium ions are bound to the calcium carbonate slurry due to soda. The cycle is repeated many times under the electrodes until an acceptable degree of tungsten leaching into solution and the formation of Fe (OH) ₂ Cl sludge.

The method can be carried out in an apparatus, the diagram of which is illustrated in FIG. 1 and in plan along section A-A in Fig. 2.

The device includes an inclined tray 1 (made of stainless steel) with an adjustable tilt, a vibration drive 2 (TO-1000 type), elastic elements 3, a loading hopper 4, an unloading hopper 5, a branch pipe 6 for supplying a solution, a threshold 7 for draining a solution, for draining a suspension from When the process is stopped, a shutter is provided in the tray 8. The device has at least one 9-discharge current electrode connected through a capacitor to a high-voltage network. The electrode 9 in the form of a steel tube in fluoroplastic insulation 10 is fixed in the window of the tray 1 in the insulating sleeve 11 on the removable cover 12. In the upper part, the electrode connected by the contact to the current source is equipped with an air supply fitting 13. The electrolyte is poured into the tray 1 with the tilt regulator 14 at the level c 15, which sets the threshold 7. To protect the finished solution from the loaded slag, a rotary damper 16 is installed with a gap over the threshold with the formation of a drain siphon 17.

The device works as follows. Vibratory drive 2 drives the inclined tray 1, mounted on elastic elements 3 (inclined springs), in an oscillatory motion, providing a directional oscillation of the tray at an acute angle of 30-40 ° to the horizon. Granular granular slag with a grain size of 0.5-4 mm is fed to the tray 1 from the loading hopper 4 with a regulating damper 16. Under the action of vibration vibrations, the granular material moves along the tray 1 from bottom to top to the unloading hopper 5. Towards the moving material, an aqueous solution of the composition in g / l, heated to 70-90 ° C in the heat exchanger, is fed from the adjustable branch pipe 6: soda - 10-20; sodium hydroxide - 5-10; sodium chloride - 10-30.

Under the action of directional vibrations, the slag in the solution moves in the form of a vibrating slurry layer, and is dewatered at the end of the tray.

A spark discharge of current from the needle electrode 9 to the bottom of the tray 1 acts on the fluidized bed of the suspension in a periodic cycle. Air is supplied through the electrode 9 to the discharge zone, where it is ionized and promotes the oxidation of iron that binds tungsten.

Example: The test of the method was carried out in the cell of Fig. 3. The cylindrical plexiglass cell 1 is fixed on an electromagnetic vibration drive 2 of the NTB-10 brand, with inclined springs 3, providing directional vibrations for the rotation of the fluidized bed. Into cell 1 are immersed (with the possibility of adjusting the immersion depth in couplings 7) electrodes 4 of high voltage current with fluoroplastic insulation 6 from the DE-26 transformer through a diode with a capacitor. Electrode 4 in the form of a stainless steel tube through which air is supplied from the oxygen cushion.

Weigh 50 g of granulated slag with a grain size of 1-2 mm, containing 1.8% tungsten; 23.4% iron; 43.4% silicon dioxide, 13.7% calcium oxide are loaded into the cell. The cell is filled with 100 ml of heated solution, composition in g / l: soda-15; sodium hydroxide-7; sodium chloride-10. Include an electromagnetic vibrator with an adjustable voltage with an oscillation frequency of 50 Hz. Granular slag forms a moving boiling suspension in solution. Air was passed through the electrode. The high voltage transformer turns on. A spark discharge between the electrodes at a voltage of 10 kV passed through the boiling suspension. A sample for tungsten was periodically taken from the cathode cell. After 1 hour, the tungsten content in the solution in g / l is 2.6; after 2 hours - 5.8; after 3 hours - 8.7. Extraction of tungsten in solution 96%. Experience shows the implementation of the process.

The technical result of the invention is expressed in the effect on the vibro-boiling layer of a suspension of slag grains in a soda-alkaline solution with the simultaneous effect of a high voltage spark discharge with air supply to the discharge zone.

The proposed method makes it possible to selectively extract tungsten into solution in a continuous mode using a vibrating apparatus for the subsequent separation of tungstic acid by known methods.

Claims (2)

1. A method for leaching tungsten from slags of smelting tin raw materials in an alkaline solution, characterized in that the leaching is carried out in an aqueous solution containing, g / l: soda 10-20, sodium hydroxide 5-10, sodium chloride 10-20, which is heated to 70-90 ° C, fed to the slag in the form of granules with a grain size of 0.5-4 mm and exposed to vibrational vibrations with a frequency of 30-50 Hz and an amplitude of 0.5-4 mm, directed at an angle of 30-40 ° with the formation of a moving vibrating layer suspension, which is exposed to a spark discharge with a potential of 10-30 kV with the supply of air through the electrode to the discharge zone with the formation of a solution of sodium tungstate. 2. An apparatus for leaching tungsten from slags of smelting tin raw materials, containing a tray with a vibrator, a feed hopper and a device for feeding and discharging solution, characterized in that the tray with a vibrator is made to provide directional vibration of the tray at an angle of 30-40 ° to the horizon, when In this case, at least one electrode in the form of a steel tube in fluoroplastic insulation is installed in the middle part of the tray cover, connected through a capacitor to a high-voltage network, configured to supply air through the electrode to the discharge zone.

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