The method of extracting precious metals from silver-containing concentrates and device for its implementation

 

(57) Abstract:

The invention relates to metallurgy, in particular to the recovery of precious metals from silver-bearing concentrates. Retrieval method includes creating in the furnace reaction volume based on the flux melt and cumulative smelting of the concentrate ore-thermal mode with periodic draining the upper part of the melt, as well as draining and separation of slag and alloy. Before smelting the concentrate is subjected to oxidative roasting, flyusovye melt is created based on the silicate-block" module of 2.0-2.5, and fluorspar in the ratio of 10: 5-1. Melting is carried out at a temperature of 1300-1600°C. a Device for extraction of precious metals from silver-bearing concentrates includes ore-smelting furnace containing a stationary arch-flue, metal case, having the ability to rotate on an axis, is placed in the case of a melting bath, made of refractory material, is equipped with a drain tray at the top, the electrodes lowered into the working space at the top. The axis of rotation of the housing is located on the side opposite the drain tray, the electrodes are located in the space of the melting bath with the ability to change the interelectrode is on has a rectangular shape with a minor axis dimension of not more than six diameters of the electrode, along the long axis of not more than twelve diameters of the electrode. The proposed method in the proposed device can carry out daily processing several tons of silver concentrate with high recovery of precious metals in the alloy. 2 S. p. f-crystals, 1 Il.

The invention relates to metallurgy, in particular to the recovery of precious metals from silver-bearing concentrates, and can be used for direct pyrometallurgical processing of large amounts of silver flotation concentrates.

Known methods of processing silver-containing concentrates of copper and lead production [1].

In the known methods of silver concentrates are used as acidic fluxes when converting copper matte or mine smelting of lead concentrates. When this noble metals collectorate matte or rough lead and retrieved in the course of their processing.

The disadvantages of this method is high transportation costs associated with delivery of silver concentrates on metallurgical plants, as well as significant losses of noble metals caused nohoper is a possibility of direct pyrometallurgical processing of silver-bearing concentrates directly on the place of their reception.

The method for extracting noble metals from silver-bearing concentrates [2].

In the known method of flotation concentrate Dyatkovo GOK chemical composition, wt.%: SiO2- 56,00; Al2O3- 8,00; Fe2O3- 9,80; CaO - 2,46; MgO - 4,13; Na2O - 4,85; Pb - 2,95; Cu - 1,21; Zn - 3,10; As - 0,15; Ag - 20158 g/t; Au - 19.9 g/t were subjected sulfamethizole firing up the ratio of sulfide sulfur to sulfate is 1:2-1:3. The resulting calcine is melted flux, consisting of technical soda and fluorite in the ratio cinder : soda : fluorite = 10:12:1. While lead and copper can be recovered from the reaction

PbS + PbSO4---> 2Pb + 2SO2,

Cu2S + CuSO4---> 3 C satellite + 2SO2.

Recovered metals (copper and lead) served as an internal collector for particles of noble metals. Extract from the candle in a metal alloy made up of (%): silver - 94,4; gold - 95,1.

The disadvantages of this method are: first, not enough high recovery of precious metals in the alloy, and secondly, the complexity of the implementation sulfatizing firing with a given ratio of sulfide sulfur to sulfate, third, mnogovershinnoe, due to the separate implementation of the operation is and, due to the use of a muffle kiln and shaft - crucible furnaces for melting (annual production of silver concentrate on Dukalska Plant reaches several tens of thousands of tons).

The method for extracting noble metals from gravity concentrates [3].

In the known method, gravity gold-silver concentrate, consisting mainly of arsenopyrite (FeAsS) and pyrite (FeS2), were subjected to oxidative calcination in a muffle furnace to destroy sulphides, separation of arsenic and sulfur in the gas phase and obtain a calcine in the form of porous hematite (Fe2O3). The resulting calcine was satawalese technical soda and silica in the ratio cinder : soda : quartz = 3:5:2 and melted in the presence of a reducing agent in the shaft-furnaces on Gelezinkeliai slag and gold-silver alloy.

The disadvantage of this method is the low productivity of the process, due to the small mass of the candle, once loaded into the crucible.

There is a method adopted for the prototype, recovery of noble metals from intermediates and device for its implementation [4].

In the known method, including the creation of the in, draining and separation of slag and alloy of noble metals, according to the invention, first form the lower part of the reaction furnace volume of the more refractory of sodium silicate loading of sodium carbonate with silica sand or broken glass and melting at 1150-1250oC, then form the upper part of the reaction volume loading and melting of sodium carbonate to 1000-1100oC with subsequent loading into the melt blended material can withstand before the end of the reaction slagging impurity metals and deposition of noble metals in the viscous layer of refractory slag and drained upper fusible slag, repeatedly loading the charge materials and the drain of fusible slag, and after draining the last portion of fusible slag melt to a fluid condition of the lower refractory slag and alloy of noble metals, merge them and separate the alloy from the slag.

The known device for implementing the method includes a two-electrode ore-smelting furnace, comprising a metal casing, lined with magnesite brick, made in the form of a cylinder with a cone at the bottom and the outlet at the bottom of the cone, according to the invention, the oven made with Tomo method in the known device can be realized cumulative smelting intermediates with low (0,5-2,0%) content of precious metals.

The disadvantages of this method are: first, not enough high recovery of precious metals in the alloy, due to the low fluidity of the slag on the basis of sodium silicate at a temperature of 1150-1250oC secondly, the significant duration of the process due to the duration of cooking ("cooking") silicate slag of technical soda ash and quartz sand (broken glass).

A disadvantage of the known device is the necessity of having two notches for selective wylewki melt, which complicates the maintenance of the furnace during the processing of a large number of intermediates.

Known furnace, taken as a prototype for electrothermal melting noble metals, comprising a housing, a melting bath, refractory lining, electrodes, descending to the workspace above, characterized in that the melting bath is made of refractory brick and is located in the frame, framing her outside established in the housing can be rotated on located on the diagonal axes and provided with clamping screws [5].

In the known furnace installation frame on axes located diagonally, allows selective spout ity implement in her high-temperature melting processes in the whole volume of the melting bath, due to the fixed spatial arrangement of the electrodes, determining the impossibility of creating in the furnace bath regulated power mode.

Object of the invention is a method and device that allows the technical result - high temperature processing of the large number of silver-bearing concentrates and provides high recovery of noble metals with high performance by creating an optimal reaction volume and adjustable power mode in it.

This technical result is achieved in that in the method of extracting precious metals from silver-bearing concentrates, including melting, and by creating in the furnace reaction volume based on the flux melt, boot into the melt and the cumulative melting concentrate ore-thermal mode with periodic draining the upper part of the melt, as well as draining and separation of slag and alloy according to the invention, before smelting the concentrate is subjected to oxidative roasting, flyusovye melt is created based on the silicate-block" module of 2.0-2.5, and fluorspar in the ratio of 10:5-1, and the melting is carried out at a temperature of 130 which engages ore-smelting furnace, containing stationary arch-flue, metal case, having the ability to rotate on an axis, is placed in the case of a melting bath, made of refractory material, is equipped with a drain tray at the top, the electrodes lowered into the working space from above, and is characterized by the fact that the axis of rotation of the housing is located on the side opposite the drain tray, the electrodes are located in the space of the melting bath with the ability to change the interelectrode distance on the order of three to nine diameters of the electrode centers at the electrodes, and the melting bath has a rectangular shape with a minor axis dimension of not more than six diameters of the electrode, along the long axis of not more than twelve diameters of the electrode.

The method is carried out in the device, shown schematically in the drawing.

The device is an ore-smelting furnace, consisting of a rectangular metal housing (1) having the ability to rotate on an axis (2), wedge-shaped tapering in the lower part (3) placed in the enclosure melting bath (4), made of magnesite bricks (5) equipped with a drain tray in the upper part (6) having dimensions along the long axis (7) and to transto top with the ability to change the interelectrode distance. The furnace contains a stationary arch-gas duct (10).

The method is as follows.

The original silver-containing concentrate is subjected to oxidative roasting of obtaining candle.

In the tub ore-thermal furnace load flux on the basis of the "silicate blocks" and fluorspar, melt it, forming the reaction volume of the furnace, and the melt is approximately one third the volume of the furnace. The melt is heated to a temperature of 1300-1600oC, and then loaded into the furnace bath cinder silver concentrate so that the portion of the loaded candle covers the surface of the melt. After loading each new piece of candle, melt, boil until the establishment in it's original temperature, and load the next portion. After loading the last portion of the candle (the melt takes approximately four fifths of the volume of the furnace) furnace tilt and pour the upper part of the melt in Slavny, so to bath furnace was filled by one third, and all operations - load flux, download cinder, procooking, draining of melt - repeat. The accumulation on the furnace hearth bath furnace a certain quantity of an alloy containing noble metals, ava from slikovni using a special device is placed in the furnace bath before the establishment of ore-thermal mode and the process is repeated. The alloy containing noble metals, together with the slag removed from the mold and separating the alloy from the slag.

An example of the proposed method.

Processing was subjected to flotation concentrate Dyatkovo GOK in the number 322,5 kg moisture content of 6.3%, the following chemical composition, calculated on dry matter (%): Ag - 1,629; Au - of 49.8 g/t; Cu - 0,85; Pb - 6,8; Zn - 0,80; Fe - 5,0; Sself- 7,2%; SiO2- 65%.

The original silver-containing concentrate was prepared by melting in an ore-smelting furnace, subjecting it to oxidative roasting of obtaining candle.

In ore-smelting furnace, allowing you to load up to 200 kg of blended materials, equipped with a drain tray at the top and mechanized system of inclination of the furnace equipped with a graphite electrode with a diameter of 75 mm, allow you to change the interelectrode space with bath rectangular shape with dimensions of h mm, made of magnesite brick, downloaded the "silicate-block" module 2.0 and fluorspar FF-92 in the ratio of 5:1. Uploaded flux melted in ore-smelting mode and brought to a temperature of 1400oC. the resulting melt was held one quarter of the volume of the furnace. Then melt downloaded some the furnace and a portion of the melt is poured through the tray in Slavny. The furnace was returned to its original position, the melt was added flux and repeated the process.

Slag each discharge were weighed and analyzed for silver.

The mass of slag first drain was 141,2 kg, the content of silver in it was 0,033% or 46,6,

The mass of slag second drain was 115,3 kg, the content of silver in it was 0,015%, or 17.3

The mass of slag third drain amounted to 107.4 kg, the content of silver in it was 0,041% or 44,0,

The mass of slag fourth drain was 126,5 kg, the content of silver in it was 0,028% or 35,4,

Thus, the total mass of slag cumulative melting was 490,4 kg, and the total content of silver in it was br143.3 g or 292 g / tonne of slag.

As a result of cumulative melt was obtained 11188 g of the alloy following chemical composition (wt. %): Ag - 45,66; Au - 0,14; Pb - 50,82; Cu - is 3.08; Fe < 0,10. ( = 99,8).

Weight of silver extracted in the alloy, was 5108,44 g, and the weight of the gold extracted in the alloy, was 15,66,

In the original amount of concentrate (322,5 kg) contained 5253,52 g of silver and 16,06 g of gold. The extraction of silver in the alloy reached 97.2%, and the extraction of gold in the alloy made up 97.5%.

In affect, the tonnes of silver concentrate with high recovery of precious metals in the alloy.

Sources of information

1. Malinetskii I. N., Chugaev L. C., Borbat C. F., Nikitin M. C., Strizhka HP metals precious metals. M.: metallurgy, 1987, S. 274-280.

2. Leonov S. B., Polonsky, S. B., Gray C. I., Tomasev C. A., Martinican centuries the Method of extracting precious metals from silver-bearing concentrates //Patent RF N 2114203 on request N 97109229/02 from 30.05.97.

3. Rollers C. C. , Dubinin, N. A., Manokhin A. P. a Method of extracting precious metals from gravity concentrates // Patent RF N 1649815 on the application 4749419/02 from then on 11.10.89.

4. Dubinin, N. A., Degonskii S. C., Kravtsov, E. D., Ten Centuries, Timofeev Century. N. The method of extracting precious metals from intermediates and device for its implementation //Patent RF N 2119541 on the application 97118796/02 from 17.11.97 (Prototype).

5. Rollers C. C., Byvaltsev C. Y., Y. Emelianov E., Sinkevich A. A. Furnace for electrothermal smelting of precious metals // Patent RF N 2095441 on request N 95120524/02 from 05.12.95 (prototype).

1. The method of extracting precious metals from silver-bearing concentrates, including melting, and by creating in the furnace reaction volume based on the flux melt, boot into the melt and the cumulative melting concentrate ore-thermal mode with periodic concentrate is subjected to oxidative roasting, flyusovye melt is created based on the silicate-block" module of 2.0-2.5, and fluorspar in the ratio 10 : 5 - 1, and the melting is carried out at a temperature of 1300 to 1600°C.

2. Device for extraction of precious metals from silver-bearing concentrates, including ore-smelting furnace containing a stationary arch-flue, metal case, having the ability to rotate on an axis, is placed in the case of a melting bath, made of refractory material, is equipped with a drain tray at the top, the electrodes lowered into the working space from above, characterized in that the axis of rotation of the housing is located on the side opposite the drain tray, the electrodes are located in the space of the melting bath with the ability to change the interelectrode distance on the order of three to nine diameters of the electrode centers at the electrodes, and melting bath has a rectangular shape with a minor axis dimension of not more than six diameters of the electrode along the long axis of not more than twelve diameters of the electrode.

 

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