RU2318887C1 - Method for gold extraction from ores - Google Patents

Abstract

FIELD: processes for extracting gold from ores.

SUBSTANCE: method comprises steps of breaking ore, double-stage disintegration of it, sorting, gravitation and flotation con centration, sorption leaching, electrolytic extraction of gold and melting it. At cycles of primary and secondary disintegration of initial ore hydraulic sorting is performed for producing sand fraction of ore and drain. Then sand fraction is divided by flow for gravitation concentration and flow for secondary disintegration. Divided flow of sand fraction is fed for gravitation concentration in quantity determined according to given formula: γ gr.f. = (0.3 - 0.4)γ in.ore + (0.2 - 0.6)γ circ.load where γ gr.f - mass of sand fraction of disintegrated ore fed for gravitational concentration; γin.ore - mass of initial ore fed for primary disintegration; γ circ.load - mass of circulation load for secondary disintegration. Gravitational concentration of drain and divided flow of sand fraction are realized for producing separate gravitation concentrates and separate tails. Then gravitation concentrates of drain and divided flow of sand fraction are combined and after their combination they are divided by "gold head" concentrate and depleted gravitation concentrate. The last is subjected to intensified cyaniding for producing solid phase and gold- containing solution. Tails of gravitation concentration of drain of sorting are subjected to flotation and prepared flotation concentrate is combined with solid phase of intensified cyaniding to be subjected to sorption leaching and desorption for producing gold-containing solution. Then separate electrolytic deposition of gold from gold-containing solutions of intensified cyaniding and sorption leaching is performed for producing separate cathode deposits of gold. Produced " gold head" and cathode deposits of gold are subjected to calcining and melting for producing gold in ingots.

EFFECT: lowered losses, increased degree of gold extraction, reduced circulation load and therefore improved efficiency of gold extraction.

1 dwg

Description

The invention relates to methods for extracting precious metals from ores according to a combined scheme, including gravity, flotation, hydrometallurgical, pyrometallurgical processes. It can be used in gold mining at deposits, including refractory ores and ores with a low content of heavy sulfide fraction.

Known technological schemes for the extraction of gold from ores and concentrates, including crushing and grinding of ore, classification in hydrocyclones, gravitational enrichment of sands of hydrocyclones, concentration and hydrometallurgical operations [Complex for processing gold-bearing ores, RF patent 205 5 643], [Metallurgy of precious metals / Kotlyar Yu .A., Meretukov MA, Strizhko LS / Moscow / MISIS / Publishing House "Ore and Metals", 2005, Volume 1, pp. 177-182].

A disadvantage of the known methods is the insufficiently complete separation of gold at the stage of gravitational enrichment, which reduces the total extraction of gold, the high circulating load of the metal during ore preparation.

The prototype of the invention is a method for extracting gold from refractory gold-bearing ores [Method for extracting gold from refractory gold-bearing ores, RF patent 2275437], including ore crushing, two-stage grinding, classification, flotation concentration, sorption cyanide, desorption, electrolytic separation and smelting.

The disadvantage of the prototype is the ingress of gold, disclosed in the first stage of grinding, to re-grinding, its abrasion, transition to the emulsion state in the sludge and subsequent loss in the tailings. In addition, the disadvantage is the high circulating load of gold in the process of ore preparation, which reduces the efficiency of gold extraction.

The objective of the invention is to increase the efficiency of gold recovery by reducing losses, increasing gold recovery, reducing the circulating load of gold.

The problem is solved in that in a method for extracting gold from ores, including ore crushing, two-stage grinding, classification, flotation concentration, sorption cyanidation, electrolytic gold separation and smelting, according to the invention, hydraulic classification and gravity concentration are carried out in a cycle between primary and secondary grinding of ore. Separately, gravitational enrichment of the discharge of classification and sand fraction is carried out, receiving separate concentrates and separate tails. The sand fraction of the classification is continuously divided into two streams - a stream for gravitational enrichment and a stream for secondary grinding. The flow directed to gravitational enrichment is calculated by the formula:

γ _{gravity supply} = (0.3-0.4) γ _{initial ore} + (0.2-0.6) γ _{circulation load} ,

Where

γ _{gravity supply} - the amount of sand fraction of the crushed ore supplied to gravity processing, weight units,

γ of the _{initial ore} is the amount of initial ore supplied to primary grinding, weight units,

γ _{circulation load} - the amount of circulation load secondary grinding, weight units.

The flow directed to secondary grinding is ground in a closed cycle with hydraulic classification. Separately obtained gravity concentrates of the drain and sand fraction are combined. The gold head concentrate is isolated and a lean gravity concentrate is obtained.

The depleted gravitational concentrate is subsequently subjected to intensive cyanidation, then sorption leaching. The desorption of the saturated sorbent is carried out. Separate electrolytic deposition of gold from gold-containing solutions of intense cyanidation and sorption leaching is carried out. Separate cathodic gold deposits are obtained.

Conduct flotation enrichment of the tails of gravity enrichment plum classification. The resulting flotation concentrate is combined with a solid phase of intensive cyanidation on sorption leaching.

The gold head concentrate is subjected to oxidative roasting, smelting and gold bullion is obtained.

The flotation dressing tailings and the spent cyanide sorption leaching solution are dump.

The technical result of the invention is the hydraulic classification between the first and second stages of ore grinding, which contributes, firstly, to the separation of gold disclosed in primary grinding, to reduce the possibility of overgrinding gold to an emulsion state and to reduce its loss in sludges and tails and, secondly , makes it possible to grind ore particles in the second stage with gold not disclosed in the first stage in a closed cycle, ultimately helping to reduce gold losses and increase it from drives.

The technical result of the invention is also the hydraulic classification in the cycle of primary and secondary grinding and the simultaneous separation of gold from the combined ground ore of both stages of grinding, which helps to reduce the circulating load of gold and reduce the amount of equipment.

The technical result of the invention is also a controlled supply of gravitational enrichment by separation from the total flow of sand fraction in an amount that is determined by the following formula:

γ _{gravity supply} = (0.2-0.4) γ _{initial ore} + (0.2-0.6) γ _{circulation load,}

which is sufficient and necessary to reduce the circulating load of gold, reduce the amount of equipment, increase gold recovery.

The technical result is also separate gravitational enrichment of the discharge and sands of hydraulic classification, which determines the homogeneity of the material of gravitational fineness, which contributes to an increase in gold recovery for gravitational enrichment operations.

The technical result of the invention is also the allocation of the concentrate of the "golden head" at the stage of gravitational enrichment, contributing to an increase in recovery due to the extraction of gold of gravitational fineness, which can be lost with tails during flotation enrichment.

The technical result of the invention is also a sequential two-stage hydrometallurgical extraction of gold from a depleted gravity concentrate, first by intensive cyanidation, then by sorption leaching of the liquid phase of intensive cyanidation pulp, which helps to increase the through extraction of gold from ore and reduce metal losses with tailings.

A description of the method for extracting gold from ores is illustrated by the drawing, which shows the technological scheme with the numbering of operations. The method is as follows.

The initial ore with a grain size of 1000 mm is crushed (1) in a jaw crusher up to 250 mm. Crushed ore is ground (2) in the first stage by a wet method in a semi-self-grinding mill. Get crushed ore up to 12 mm and send it to screening (3) in the buter. Get minus 12 mm ore and galyu. Galya is crushed (4) and returned to grinding (2) in the mill. From butara, the crushed ore is sent for classification (5) to hydrocyclones, for example, 4 batteries of 2 650 GVX hydrocyclones each. Get sands and sink. Separate gravitational enrichment is carried out.

Determine the flow of sand for gravitational enrichment as follows. Set the circulation load in accordance with the allocation of the flows of crushed pulp and sand hydrocyclones. The flow is calculated by the formula:

γ _{gravity supply} = (0.2-0.4) γ _{initial ore} + (0.2-0.6) γ _{circulation load} ,

Where

γ _{gravity supply} - the amount of sand fraction of the crushed ore supplied to gravity processing, weight units,

γ of the _{initial ore} is the amount of initial ore supplied to primary grinding, weight units,

γ _{circulation load} - the amount of circulation load secondary grinding, weight units.

The flow obtained by calculation is directed, for example, alternately from four to five hydrocyclones to screening (6) screens, for example, vibrating ones. The sublattice screening product is fed to gravity enrichment (7).

The remaining stream of classification sands (5) together with the over-screening product of screening (6) is sent to a ball mill for secondary grinding (8). The crushed ore is sent for classification (5) in hydrocyclones. Hydrocyclones and a ball mill are connected in a closed cycle.

Gravitational enrichment (7) of sands is carried out. Use a gravity apparatus, such as a Knelson centrifugal concentrator with periodic unloading.

Gravitational enrichment is carried out (9) for the discharge of hydrocyclones separately from the sand also in centrifugal apparatuses and gravity concentrate and gravity enrichment tailings are obtained.

The sand gravity concentrate and hydrocyclone discharge gravity concentrate are combined and sent to screening (10) in the 1 mm class, on screens, for example, on a multi-frequency screen ULS. Screening (10) is carried out in a closed cycle with regrinding (11) to minus 0.15 mm. The under-screening product of the screen is sent for finishing operation (12) on the concentration table. Get the gold head concentrate and depleted gravity concentrate. The gold head concentrate is thickened (13). The drain is directed into circulation.

The depleted gravitational concentrate is successively concentrated (14) with the addition of known flocculants, then alkalinized with a solution of alkali in a vat with a mixing device. The thickened depleted gravitational concentrate is sent for intensive cyanidation (15). A 20% sodium cyanide solution is introduced into the reactor with a stirring device and cyanide at an initial NaCN concentration of 3% and a temperature of 60 ° C for at least 4 hours. Saturated pulp is filtered (16) on a press filter to obtain the filtrate and tails of intense cyanide. The filtrate is sent to electrolytic deposition (17) in an electrolytic cell, a cathode deposit is obtained and it is accumulated.

Gravity concentration tailings (9) are sent to flotation concentration (18), including the main and control flotation in an open cycle. Flotation is carried out in tank type flotation machines, for example pneumomechanical FPM-UP-100. Famous flotation reagents are used: collector - butyl xanthate and blowing agent - Flotanol C7 flotanol. Reagents are fed to the contact tank. Get flotation concentrate and tails. The flotation concentrate is concentrated (19) by adding known flocculants, for example magnafloc 1011, and made alkaline (20), for example, with a 20% solution of caustic soda to a pH of 10.5-10.8 in a vat with a stirrer. The flotation tailings are condensed (21), the discharge is directed into circulation, and the condensed product is sent to the tailing dump.

After alkalization, the flotation concentrate (20) is combined with intensive cyanidation tails (15) after filtration (16) and sent to sorption leaching (22). A cascade of vat type apparatuses with mixing devices and submersible screens is used. The process is conducted in countercurrent: sodium cyanide is a sorbent. Activated carbon, for example LC0612, is used as a sorbent. Get coal saturated with gold and spent cyanide solution. After filtration (23) and disinfection by known technologies, the cyanide solution is stored in the form of solid tails at a special landfill and the liquid phase in a tailing dump.

Saturated coal is separated on a vibrating screen, washed and sent to desorption (24) with simultaneous regeneration processes and electrolytic deposition. Gold cathode deposit is obtained and accumulated.

Waste coal is regenerated and sent for reuse. The spent electrolyte is restored by known methods and also returned to the process.

The "Golden Head" and cathode deposits after accumulation are processed separately. Oxidative firing is carried out (25), for example, in a multi-hearth furnace. After oxidative firing, smelting (26) is carried out with the addition of fluxes, for example, in an electric arc furnace. Get gold alloyed bullion.

The method of extracting gold from ores by reducing gold loss, increasing gold recovery, reducing the circulation load of gold in the ore preparation process and reducing the amount of equipment helps to increase the efficiency of gold recovery.

Claims (1)

A method of extracting gold from ores, including crushing ore, two-stage grinding, classification, gravity and flotation concentration, sorption leaching, electrolytic separation of gold and smelting, characterized in that in the cycle of primary and secondary grinding of the original ore, hydraulic classification is carried out to obtain a sand fraction and discharge , the sand fraction is divided into a stream for gravitational enrichment and a stream for secondary grinding, re-grinding is carried out, while it is directed to gravel Discount enrichment divided Peskova flow fraction in an amount determined by the formula γ _{gravity supply} = (0.3-0.4) γ _{initial ore} + (0.2-0.6) γ _{circulation load} , where γ _{of gravity supply} is the weight of the separated stream of sand fraction and ground ore fed to gravity processing, γ of the _{initial ore} is the weight of the initial ore supplied to primary grinding, γ _{circulation load} - the weight of the circulation load of the secondary grinding; separately carry out gravity enrichment of the drain and the separated stream of sand fraction to obtain separate gravity concentrates and separate tails, combine the gravity concentrates of the drain and the separated stream of sand fraction and separate the combined concentrate into a gold head concentrate and a depleted gravity concentrate, which is subjected to intensive cyanidation to obtain a solid phases and a gold-containing solution, the tails of gravity enrichment drain plum classification are subjected to flotation and the obtained flotation concentrate is combined with the intensive cyanidation solid phase and subjected to sorption leaching and desorption to obtain a gold-containing solution, then separate electrolytic deposition of gold from gold-containing solutions of intensive cyanidation and sorption leaching is carried out, and separate cathodic gold precipitates obtained “gold head” and gold is fired, smelted and get gold bullion.