RU2224806C1 - Gold- and silver-containing floatation concentrates production line - Google Patents

Abstract

FIELD: metallurgy of noble metals; hydro-metallurgy of gold and silver. SUBSTANCE: gold- and silver-containing concentrates production line includes preliminary cyanidation module, module of sorption of gold on activated carbon, module of de-sorption of gold from saturated carbon, carbon regeneration module, gold-containing solution electrolysis module and secondary concentration module. Line is additionally provided with tailing pond and silver gas reduction module located at inlet of reusable solution from tailing pond . Silver gas reduction module includes receiver and settler with systems of dispersers which are connected with gas source by means of pipe line and is connected with preliminary cyanidation module. EFFECT: increased extraction of gold and silver from floatation concentrates to 95.5 and 65% respectively. 6 Dwg

Description

 The invention relates to the field of metallurgy of noble metals, in particular to the hydrometallurgy of gold and silver.

 A well-known instrumentation line for the extraction of gold from ores of the Morro do Ouro deposit located in the northwest of the state of Minas Gerais of Brazil, in which, during the technological process, an ore crushing module, an ore grinding module with 80% of the fineness grains less than 20 microns, flotation enrichment module for grinding products, gravity enrichment module for flotation centers, gold leaching module from residual flotation concentrate with cyanide atrium and gold extraction module from the pulp by sorption on activated carbon, followed by desorption of gold with a saturated carbon regeneration and electrolysis commodity eluates (1).

 In a known line, the initial flotation concentrate is subjected to gravitational enrichment at a centrifugal concentrator with the release of coarse gold into the concentrate, and the tails of gravity treatment are fed to the preliminary leaching of gold with sodium cyanide.

 Then, the cyanized pulp is fed to the module for the sorption of gold on activated carbon and then to the modules for the desorption of gold from saturated carbon and electrolysis of eluates.

 However, the known line does not provide a sufficiently complete extraction of precious metals, in particular silver, which is lost with working solutions and solid tail fractions.

 A line for processing gold-containing flotation concentrates is also known, including the gravity-flotation purification module of the initial concentrate installed during the technological process and interconnected by vehicles, the intensive cyanidation module of the purification concentrate, the preliminary planning module, the activated carbon sorption module for gold, the saturated gold desorption module coal, coal recovery module and electrolysis module of gold-containing solutions (2).

 In this line, the initial concentrate is subjected to gravity-flotation enrichment at two plants, each of which is made in the form of an enrichment hydrocyclone with a supply, drain and sand nozzles and a concentration table connected to the sand nozzle of a hydrocyclone, a flotation machine and a ball mill connected in a closed grinding cycle with installations of the first and second stages of classification.

 Then the pulp is fed to the intensive cyanide module, which is a pulsation column connected to an autopulsator to communicate vibrations to the reagents filling the column. After the module of intensive cyanidation, the pulp enters the module for sorption of metals on activated carbon, made in the form of a sorption pulsation column. Then, saturated activated carbon enters the gold desorption module, consisting of an autoclave and a desorption apparatus. The coal recovery module is made in the form of a column of cyanide coal processing. The module for secondary concentration of precious metals is made in the form of a sorption countercurrent column. The electrolysis module of gold-containing solutions is an electrolyzer and a container for solutions, interconnected by a pipeline.

 This line is the closest to the proposed and selected as a prototype.

 The disadvantages of the prototype include the fact that when processing gold-silver concentrates on this line, a significant number of solutions are formed, characterized by a high content of silver, which should be subjected to additional processing. In addition, the known line does not provide the extraction of coarse-grained gold and silver into a separate product, which affects the extraction of metals from the solid phase during cyanidation.

 The objective of the invention is to expand the functionality of the line and increase the complexity of the extraction of metals from flotation concentrates.

 The specified technical result is achieved by the fact that the line for processing gold-containing flotation concentrates, which contains a preliminary cyanide module, a module for sorption of gold onto activated carbon, a module for desorption of gold from saturated carbon, a module for recovering gold from a gold-containing electrolysis module, is installed during the technological process and interconnected by vehicles solutions and a secondary concentration module, equipped with a tailing dump and a module for gas reduction of silver, ra located at the reception of circulating solutions from the tailings, the silver gas recovery module includes a receiver, a precipitating tank with a dispersant system connected to the gas source by a gas pipeline, and is connected to the preliminary cyanide module with the solution transporting means.

 In addition, in a preferred embodiment of the invention, the line further comprises a gravity cleaning module for the initial concentrate placed in front of the preliminary cyanide module.

 The proposed line provides the ability to reduce the loss of large and sparingly soluble particles of gold and silver by extracting them in the gravity recycle module into the gravity concentrate at the beginning of the process.

 In addition, the gas gas recovery module installed at the reception of working solutions from the tailings pond allows recovering additional silver lost during the known processing, with the possibility of direct smelting of sediments.

 The invention is illustrated by drawings, where figure 1 presents a diagram of a line for processing gold and silver flotation concentrates; figure 2 shows a patch of cyanidation, General view; figure 3 shows a patch of sorption of gold and silver; figure 4 shows the module of desorption of gold; in FIG. 5 presents a coal column; figure 6 shows a General view of the module gas recovery of silver.

 Gold and silver-containing flotation concentrate processing line according to the scheme: gravity purification of the initial flotation concentrate, cyanidation and sorption leaching using the “coal in pulp” technology, followed by desorption of metals from saturated coal, their electrolytic deposition from desorption solutions and coal recovery, recycling of recycled solutions by gas recovery of silver with subsequent smelting of precipitation contains established during the process and related sports equipment module 1 (in the preferred embodiment) of gravity cleaning of the initial concentrate, module of preliminary cyanide, module 3 of sorption of gold on activated carbon, module 4 of desorption of gold from saturated carbon, module 5 of electrolysis of gold-containing solutions, module 6 of secondary concentration, module 7 of coal recovery , module 8 gas recovery of silver.

 The gravity cleaning module 1 of the initial concentrate is intended for secondary enrichment of the concentrate by processing, for example, on a centrifugal concentrator and contains a centrifugal concentrator with a feed pipe for the initial concentrate and an intermediate product outlet pipe connected to a contact tank for receiving the intermediate product, a container for collecting gravity cleaning concentrate, which is periodically excavated, a pipe connected to the pulp feed pipe into the modal preliminary cyanide patch A preliminary cyanidation.

 The pre-cyanide module 2 is a cyanide patch consisting of a body 9, a circulator 10, an air supply pipe 11; a circulator 12 with openings 13 for circulating the pulp, a dispersant 14, into which compressed air is supplied to agitate the settled solid material, a drain pipe 15, a mounting hatch 16, a pulp supply pipe 17 and a pulp exit pipe 18 connected to the sorption patchow pulp inlet gold and silver module sorption of gold on activated carbon.

 Activated carbon gold sorption module 3 is a sectional sorption pack consisting of a housing 19, a bubbler 20 for maintaining pulp and coal in suspension, an air lift 21 for transporting coal and pulp, a drainage device 22, a pulp distributor 23, and a mesh 24 for separating coal from pulp, tray 25 for regulating the flow of coal. There are pulp holes 26, rods 27 for adjusting the position of the tray 25, hatches 28 for servicing the drainage device 22; emergency pipes 29, valves 30 on the pipes 29, repair hatch 31; a pulp inlet hole 32, a pulp outlet hole 33 connected by conveyance means (pipe, pump) to a tailing dump and a coal outlet 34 connected to a wash column that is connected to a storage tank for collecting coal from gold desorption module 4 from saturated coal.

 The gold desorption module 4 from saturated coal consists of interconnected pipelines with shut-off devices of a tank 35 for a solution of NaOH and NaCN, an autoclave 36, a stripper 37, a heat exchange device 38, a tank 39 for collecting rich eluates connected to an electrolysis module, a tank 40 for collecting poor eluates, connected to the module 6 for the secondary concentration of gold-containing solutions, a pump 41 for pumping solutions through a pipe from a tank 35 to a heat exchange device 38, a storage tank 42 for collecting coal and feeding into des Orber 37.

 The electrolysis module 5 of gold-containing solutions consists of interconnected pipelines of a container for collecting a saturated solution, a direct-flow electrolyzer, a tank for collecting a solution after electrolysis, and a pump for pumping a solution connected by a solution supply pipe to the column 43 of the secondary concentration module.

 The secondary concentration module 6 is at least two columns 43 for the secondary concentration of gold and silver from electrolysis solutions and poor desorption eluates on activated carbon, installed in cascade and consisting of a cylindrical body 44 with a conical bottom, an airlift 21, an air supply pipe 45 , coal outlet pipes 46, solution supply pipes 47, solution drain pipes 48. There is a hole 49 for supplying coal.

 The coal recovery module 7 consists of a thermal coal recovery furnace and a coal cyanide column 43.

 The thermal coal regeneration furnace is designed to process coal after temperature desorption in order to remove organic substances accumulated in the coal during sorption, and is made in the form of a rotary drum furnace.

 Column 43 for cyanide processing of coal is designed to restore the sorption properties of coal and is made in the form of a cylindrical body 44 with a conical bottom, an air lift 21, an air supply pipe 45, a coal outlet pipe 46, a solution supply pipe 47, and a solution discharge pipe 48 from the column.

 Silver gas recovery module 8 consists of a precipitating tank 50, which is a cylindrical tank with a conical bottom, and a dispersant system 51 installed inside, connected by a gas pipeline 52 to a compressor 53 to create hydrogen pressure in the system, a receiver 54, and a gas source 55, pipes 56 for condensate discharge from the receiver, with a valve 57, pipe 58 for dumping the solution from the precipitation tank connected to the cyanide patch of the preliminary cyanine module with the valve 59, pipe 60 to discharge the precipitate from the precipitation tank engine 61, pipes 62 with a valve 63 for supplying solutions from the tailings 64, a contact tank 65 for preparing a precipitating agent with a pipe 66 for supplying a reagent to a precipitating vessel with a valve 67, a pressure relief valve 68 and a valve 69 for closing the gas supply pipe from a source of 55 gas.

 The line works as follows.

 The initial flotation concentrate containing, for example, 100 g / t Au, 110 g / t Ag, 50% sulfides Fe, Zn, Cu with a mass fraction of solids in the pulp of 45% after separation of wood chips enters the gravity cleaning module to extract free gold and silver in separate product - gravity concentrate.

 In module 1 of gravitational cleaning of the initial concentrate, the floc concentrate enters a centrifugal concentrator with the intermediate product entering the contact tank and then into the cyanidation patch pipe 17 of the preliminary cyanide module 2.

 A gravity concentrate containing, for example, 1,500 g / t of gold and 2,000 g / t of silver is periodically (as it accumulates) removed from the centrifugal concentrator to a container for collecting the gravity treatment concentrate and then, after drying, is sent, for example, to smelting or additional cleaning.

 The intermediate product obtained after gravitational refining that does not contain large free particles of noble metals is sent for cyanide in a cyanide patch. The pulp is fed into the patch through the pipe 17, then it enters through the openings 13 for circulation of the pulp to the circulator 12, where, enriched by the air entering through the pipe 11, it acquires a density lower than the density of the pulp in the volume of the apparatus, rises along the central pipe and pours out through its upper edge, thus, mixing and enriching with oxygen, necessary for cyanidation.

 At the same time as pulp, a strong NaCN solution, for example 15%, is supplied to the cyanidation patch in such a volume as to ensure and maintain a NaCN concentration of, for example, 0.35% during the entire cyanidation process, which lasts about 12 hours.

 The extraction of gold and silver in the patch of cyanidation is at least 80% and 60%, respectively.

 Upon completion of cyanidation, the pulp from the patch is cyanide is fed through the pipe 18 and the hole 32 into the patch of sorption module 3 sorption of gold on activated carbon.

 The principle of operation of patchachi sorption is similar to the principle of operation of patchachi cyanide.

 The pulp is fed into the volume of patchuca, mixed with fresh activated carbon coming from module 7 and circulated under the action of a bubbler 20, maintained in suspension, then transported by airlift 21 to grid 24, where coal grains are held up and rolled down on tray 25 to the previous section, and the pulp, passing through the holes of the mesh 24, enters the next section.

 Thus, using the drainage device 22 of the sectional patch, which separates the flow into two products and transfers them in different directions, the principle of pulp countercurrent is carried out - activated carbon in the process of sorption leaching.

 The pulp from the last section of the patchoux through the hole 33 after dilution with water is sent by the pump to the tailing pond 64, from where the settled solution containing, for example, 0.2 mg / l of gold and 35 mg / l of silver is sent to module 8 for gas reduction of silver.

 Activated carbon saturated with noble metals, containing, for example, 12 g of gold per 1 kg of coal and 10 g of silver per 1 kg of coal, enters the wash column through hole 34, and after washing in the wash column (not shown) from pulp, sludge and wood chips by passing water through a layer of coal and airlift is fed into the storage tank 42 module 4 desorption of gold from saturated coal.

In module 4 for desorption of gold from saturated carbon, activated carbon saturated with noble metals from the storage tank 42 is fed to the stripper 37. At the same time, a cyanide-alkaline eluent from the tank 35 is fed through the heat exchanger 35 to the autoclave 36, where it is heated to a temperature of 145-150 ^o С and at a pressure of about 1 MPa, it is supplied to the stripper 37 charged with saturated carbon.

 The eluent passes under pressure through a layer of coal in stripper 37 and, eluting gold and silver from it, carries out desorption.

The eluate, containing 150-900 mg / l of gold and 100-400 mg / l of silver, is fed from stripper 37 to a heat exchanger 38, where it transfers heat to the eluent again supplied to the autoclave 36, and is sent to a container 39 for collecting rich eluates, from where after cooling to a temperature of 20-30 ^o With sent to the module 5 of the electrolysis of gold-containing solutions.

 The rich eluate is fed to the electrolysis module 5 of gold-containing solutions, where the electrolytic deposition of gold and silver is carried out to "deplete" the electrolyte to achieve a residual concentration of 20 mg / l of gold and silver, the specified degree of de-metalization is achieved by regulating the flow of the solution and maintaining a sufficient current density. The electrolysis solutions are sent to the module 6 of the secondary concentration. The cathode deposit of the electrolyzer is sent to the smelting.

The eluate containing up to 150 mg / l of gold and 100 mg / l of silver after stripper 37 and heat exchanger 38 is sent to a container 40 for collecting poor eluates and, after cooling to a temperature of 25-30 ^o C, is combined with an electrolysis solution and sent to module 6 of the secondary concentration.

 Upon completion of the desorption process, the pressure in the stripper 37 is released to atmospheric and the desorbed coal is unloaded.

 After desorption, the coal is sent to the coal regeneration module 7, where, passing through a rotary thermal regeneration drum furnace, it restores sorption properties by burning off organic impurities accumulated in the pores of the coal during the sorption cycle.

 After processing in the furnace, the coal is sent to the column 43 for cyanide processing of coal, where it is processed with a 0.1% cyanide solution, which is fed into the solution supply pipe 47 and passes through the coal layer, due to which metal gold and silver dissolve, contained in coal, and the simultaneous formation and sorption of cyanide complexes of noble metals.

 Coal is discharged from column 43 by airlift 21 through pipe 47 to module 3 for sorption of gold onto activated carbon or to module 6 of secondary concentration.

 The secondary concentration of gold and silver from a poor eluate and an activated carbon electrolysis solution circulating in a closed circuit between the gold desorption module 4 from saturated carbon and the secondary concentration module 6 is carried out in columns 43 installed in cascade. The solutions are fed into the lower part of columns 43 through pipe 47. In this case, coal is fed into the last of the installed columns, and solutions are fed into the head column. Coal and solutions are moved in countercurrent mode, and the solutions move by gravity, and coal using aerial lifts 21.

The solution from the tailings 64 is fed through a pipe 62 to the precipitating tank 50 until, for example, 2/3 of the volume of the apparatus is filled, and then the valve 63 is closed. The solution of the precipitating agent, for example, ferric iron or starch, prepared in the contact tank 65 is fed into the tank -collider 50, after which the valve 67 closes. The valve 69 opens, from a gas source 55, for example, a hydrogen cylinder, hydrogen is supplied to the gas pipeline 52 and fills the gas pipeline-receiver-sedimentation tank system, the valve 69 closes, then the compressor 5 is turned on 3, the movement of hydrogen begins in the direction from the receiver 54 to the precipitating tank 50, where the atomization of hydrogen occurs through a system of dispersants 51 in the solution throughout the apparatus and the process of gas reduction of silver begins. The reduction of silver occurs due to the action of hydrogen on the NaAg (CN) ₂ complex, resulting in the formation of metallic silver, which, being in a suspended colloidal state, is deposited on the introduced reagent-precipitator. The reagent-precipitant is maintained during the entire recovery process in suspension by introducing hydrogen under pressure, which causes the solution to circulate.

 After the recovery of silver, for example, within 15-20 minutes, the valve 69 closes, the pressure relief valve 68 opens and the pressure is released from the system. After a complete pressure relief, if necessary, the accumulated condensate is discharged from the receiver 54 through the pipe 56 by opening the valve 57. Then, the precipitating reagent is completely precipitated and the solution is discharged through the pipe 58, opening the valve 59. A precipitate containing, for example, 1200 mg / g silver , drained through a pipe 60, dried and sent for melting. After reconstitution, solutions containing 1.7 mg / L of silver and 0.2 mg / L of gold are reinforced with cyanide and sent to the preliminary cyanide module.

 Before starting the next recovery cycle, the shutters 61, 59, 57 and the pressure relief valve 68 are closed.

 The recovery of silver from tailings solutions is 95%.

 Thus, the proposed line due to the distinctive features made according to the invention, due to the introduction of an additional module for gas reduction of silver allows you to extract up to 65% of silver by extracting it from working solutions.

 In addition, the removal of large free particles of noble metals from the initial flotation concentrate that are hardly soluble in a cyanide medium into a separate product, a gravity concentrate rich in the content of noble metals, can increase the extraction of gold and silver to 95.5% and 65%, respectively, unlike prototype, where the initial concentrate is subjected to complex expensive gravitational-flotation redistribution to obtain a product that requires additional processing planning in a separate cycle.

 The exception of the operation of dividing the initial concentrate into 3 products, in contrast to the prototype, avoids the operations of pulping and intensive planning of the concentrate cleaning.

The introduction of an additional reagent, sodium cyanide, into the desorption operation allows more complete removal of precious metals from coal: residual concentrations of precious metals, respectively, 0.08 g of gold and 0.35 g of silver per 1 kg of coal, and also reduce the temperature of the desorption process to 145 -150 ^o C, which significantly reduces the energy costs of heating the solutions, in contrast to how it is done in the prototype, where the solutions are heated to a temperature of 165-175 ^o C, and the residual concentration of gold in coal after desorption - 0.1 g / kg

 An additional operation of thermal regeneration of coal, introduced in the module 7 of coal recovery, allows you to more fully restore the sorption properties of coal, which in turn leads to more efficient use of the sorbent, that is, its economy and increase recovery.

Used sources
1. Review journal "Mining" 4, A75, 1989

2. RF patent 2062797, IPC ⁶ C 22 V 3/62, 11/00. Publ. 06/27/96.

Claims (1)

A gold and silver-containing flotation concentrate processing line containing a preliminary cyanation module installed during the technological process and interconnected by vehicles, a module for sorption of gold on activated carbon, a module for desorption of gold from saturated carbon, a module for recovering coal, an electrolysis module for gold-containing solutions, and a secondary module concentration, characterized in that it is equipped with a tailing dump and a gas gas recovery module located on the Birmingham circulating solutions of tailings, the silver gas recovery unit includes a receiver, a vat-nonsolvent dispersant system connected to a source of gas pipeline, and is connected with the module transporting means prior cyanidation solutions.

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