阅读说明：本技术 含砷金精矿的回收方法 (Recovery method of arsenic-containing gold concentrate ) 是由 熊先学 王金虎 张平 王义凤 王梦成 于 2020-06-16 设计创作，主要内容包括：本发明提供了一种含砷金精矿的回收方法,该方法包括如下步骤：(1)将含砷金精矿进行焙烧和研磨；(2)将经焙烧和研磨的含砷金精矿进行氰化浸出；(3)分离出浸出液和氰渣,该步骤的浸出液记为第一浸出液；(4)向所述氰渣中先后加入酸度调节剂和络合剂,在浸出后分离出浸出液和浸渣,该步骤的浸出液记为第二浸出液；(5)分别将第一浸出液和第二浸出液进行置换提金,从而回收金。该方法具有高的金回收率且同时能够有效避免铜被浸出。(The invention provides a method for recovering arsenic-containing gold concentrate, which comprises the following steps: (1) roasting and grinding the arsenic-containing gold concentrate; (2) cyaniding and leaching the roasted and ground arsenic-containing gold concentrate; (3) separating a leaching solution and cyanogen slag, wherein the leaching solution in the step is marked as a first leaching solution; (4) adding an acidity regulator and a complexing agent into the cyanogen slag in sequence, separating a leaching solution and leaching slag after leaching, and marking the leaching solution in the step as a second leaching solution; (5) and (4) replacing and extracting gold from the first leaching solution and the second leaching solution respectively, thereby recovering gold. The method has high gold recovery rate and can effectively prevent copper from being leached.)

1. A method for recovering arsenic-containing gold concentrate, the method comprising the steps of:

(1) roasting and grinding the arsenic-containing gold concentrate;

(2) cyaniding and leaching the roasted and ground arsenic-containing gold concentrate;

(3) separating a leaching solution and cyanogen slag, wherein the leaching solution in the step is marked as a first leaching solution;

(4) adding an acidity regulator and a complexing agent into the cyanogen slag in sequence, separating a leaching solution and leaching slag after leaching, and marking the leaching solution in the step as a second leaching solution;

(5) and (4) replacing and extracting gold from the first leaching solution and the second leaching solution respectively, thereby recovering gold.

2. The method of claim 1, wherein the separation in steps (3) and (4) is performed by filtration.

3. A method according to claim 1 or 2, wherein the roasting is performed by a rotary kiln.

4. The method of claim 1 or 2, wherein the complexing agent is a chelate having nitrogen-containing dentitions.

5. The method defined in any one of the preceding claims wherein during the leaching of step (2) the leach solution has a pH of greater than 11.

6. A process according to claim 5, wherein the pH of the leach solution is adjusted with NaOH, CaO and/or Na₂CO₃And (6) adjusting.

7. The method as claimed in any one of the preceding claims, wherein the calcination temperature is 600-750 ℃.

8. The method according to any one of the preceding claims, wherein a leaching additive is added to the arsenic-containing gold concentrate prior to roasting.

9. The method of claim 9, wherein the leaching additives are NaOH and Na₂A mixture of S.

10. The method of any of the preceding claims, wherein the order of firing and grinding is interchanged.

Technical Field

The present invention belongs to the technical field of metal smelting, more specifically to a method for recovering valuable metals from minerals, and in particular to a method for recovering arsenic-containing gold concentrate, especially gold from arsenic-and copper-containing gold concentrate.

Background

China has rich gold mine resources and has a long gold mining history. At present, the gold reserves in China are second only to south Africa, Russia, America and Canada and live in the fifth place of the world. At present, the domestic and foreign gold dressing methods mainly comprise gravity separation, mercury mixing, flotation and cyanidation, and various combined methods or dressing and smelting combined processes are adopted to improve the gold recovery rate and grade. The cyanidation method belongs to a hydrometallurgical process, and is a mainstream method for gold production at present due to the advantages of good economic benefit, mature process, wide ore adaptability and the like.

CN101028612A discloses a closed-loop method for improving the grade and recovery rate of gold concentrate of refractory gold ore, which is especially suitable for floatation of arsenic-rich carbon fine-grained gold ore, and the method is characterized in that Na with molecular formula is added in the procedures of primary roughing and primary concentrating respectively₄P₂O₇·10H₂The sodium pyrophosphate of O accounts for 0.1-0.3% of the weight of the raw ore, and the method specifically comprises the following steps: the molecular formula is Na₄P₂O₇·10H₂Dissolving powdery or granular sodium pyrophosphate of O into sodium pyrophosphate aqueous solution by water; performing primary roughing, namely adding the sodium pyrophosphate aqueous solution into the raw ore pulp and uniformly stirring; first concentration, adding the sodium pyrophosphate aqueous solution into the gold concentrate subjected to first roughing and second roughing, and uniformly stirring; secondary concentration, namely performing secondary concentration on the gold concentrate subjected to primary concentration to obtain a final product gold concentrate; and (4) performing closed circuit check, and returning the tailings subjected to secondary concentration and the tailings subjected to primary concentration to the steps 3 and 2 respectively.

CN101041498A discloses a method for recovering valuable elements from acidic arsenic-containing biological oxidation gold extraction waste liquid, and simultaneously adding the acidic arsenic-containing biological oxidation gold extraction waste liquid and a precipitator into a reaction kettle, and realizing arsenic-iron separation through selective precipitation; solid-liquid separation is realized by adopting a filtering technology, the solid phase enters an iron oxide red preparation process, and the liquid enters a process of recovering arsenic; adjusting the solution after arsenic recovery to be neutral by using alkaline liquor, and condensing and crystallizing Na at 0-4 DEG C₂SO₄·10H₂O; recovery of Na₂SO₄·10H₂Returning the tail liquid after O to the step 1 for preparing the alkali solution.

CN101070566A discloses a gold extraction process for cyanided tailings containing gold coated by primary sulfide, which comprises the steps of firstly separating and enriching the primary sulfide containing the coated gold in the cyanided tailings by a flotation method, then carrying out ultra-fine grinding on sulfide concentrate containing the coated gold in a tower type grinding and leaching machine, carrying out alkaline normal-temperature normal-pressure intensified pre-oxidation in an intensified alkaline leaching stirring tank after the ultra-fine grinding, adding CaO milk into ore pulp after the pre-oxidation is finished, mixing the pulp, carrying out cyaniding leaching operation, and efficiently extracting gold.

CN101078050A discloses a method for floating sulfur concentrate from tailings of gold extraction by direct cyanidation, which comprises the following steps: adding gold extraction tailings into a size mixing tank 1, adding water to adjust the concentration of ore pulp to 50-60%, uniformly stirring, and putting into an acidification tank 2; adding industrial sulfuric acid to adjust the acidity pH value of the ore pulp to be 1.5-2.5, continuously stirring, keeping the pH value to be 1.5-2.5, and putting the ore pulp into a size mixing tank 3; adding water to adjust the pulp to 30-35%, and feeding the pulp into a stirring tank 4; adding a flotation agent and a foaming agent while stirring; after the ore pulp enters a flotation tank 5, performing closed-circuit flotation, and performing primary roughing, secondary closed-circuit scavenging and four-stage closed-circuit concentration to enrich sulfur elements to obtain sulfur concentrate; and pumping the sulfur concentrate into a filter press 9 through an ore pumping pump 8 for dehydration and separation to obtain high-grade sulfur concentrate.

CN 101078058A discloses a method for extracting gold by multiple roasting of refractory arsenic-containing gold concentrate, which comprises the following steps: (1) preparing materials: adding coal powder into the tailings subjected to secondary roasting, cyaniding and gold extraction according to the weight ratio of 7-10%, and uniformly stirring; (2) roasting: feeding the prepared materials into a roasting furnace for roasting, and controlling the temperature at 550 ℃ and 680 ℃; the generated flue gas is directly emptied after dust collection and purification treatment; the generated cinder enters a cyaniding procedure; (3) cyaniding: the gold and silver are recovered from the roasting slag by a conventional cyaniding gold extraction method.

US4072587A discloses a process for the selective recovery of silver and gold from cyanide solutions by precipitation of silver sulfide and subjecting the filter cake to electrolysis.

AU8873082A discloses a method for recovering precious metals from an ore slurry by simultaneous leaching and cementation with the addition of an alkaline substance, a complexing agent and a reducing agent.

EP0905264a1 discloses an improved process for the recovery of precious metals such as gold and silver, and in particular to a process for the recovery of gold from aqueous cyanide solutions by contacting cyanide containing precious metals, particularly gold, with an ion exchange resin containing guanidine functionality. The guanidine reagent extracts the gold from the aqueous solution, and the gold is then eluted from the guanidine reagent, followed by recovery of the gold by conventional means.

"experimental research for improving recovery rate of gold, silver and copper in roasting-cyanidation process of aurin ore containing arsenic copper", Xue Guang, etc. for gold, in 2005, vol 26, 5, proposes a new method for improving recovery rate of gold, silver and copper in roasting-cyanidation process of aurin ore containing arsenic copper, the method is to add sodium sulfide into aurin ore concentrate and then carry on roasting pretreatment, can improve recovery rate of gold, silver and copper effectively, the experimental result shows, leaching rate of gold, silver and copper is improved 8.22%, 57.43%, 7.82% respectively, and do not influence the acid-making and electrolytic copper process.

However, in the above prior art, the leaching rate of gold is still not high, and the discarded cyanide slag still contains a certain amount of gold and other precious metals, thereby resulting in a low total gold leaching rate and waste of other precious metals. However, if a complexing agent with strong complexing ability is used, Cu is leached out, which causes great trouble to the subsequent gold extraction process, thereby causing a situation of entering and returning to victory valley.

There is therefore a need in the art for a selective recovery method of gold with a targeted high gold recovery from arsenic-containing gold concentrate, while at the same time effectively avoiding leaching of copper.

Disclosure of Invention

In order to solve the above technical problems, the present inventors have further studied and conducted extensive experiments on the basis of the previous research, and have developed the following technical solutions through multi-party collaborative research and development.

In one aspect of the present invention, there is provided a method for recovering an arsenic-containing gold concentrate, the method comprising the steps of: (1) roasting and grinding the arsenic-containing gold concentrate; (2) cyaniding and leaching the roasted and ground arsenic-containing gold concentrate; (3) separating a leaching solution and cyanogen slag, wherein the leaching solution in the step is marked as a first leaching solution; (4) adding an acidity regulator and a complexing agent into the cyanogen slag in sequence, separating a leaching solution and leaching slag after leaching, and marking the leaching solution in the step as a second leaching solution; (5) and (4) replacing and extracting gold from the first leaching solution and the second leaching solution respectively, thereby recovering gold.

Preferably, the separation in steps (3) and (4) is performed by filtration.

The step (2) can be recorded as primary leaching, and the step (4) can be recorded as secondary leaching.

Preferably, the firing is performed by a rotary kiln.

Preferably, the complexing agent is a chelate having nitrogen-containing dentitions.

Preferably, during the leaching of step (2), the pH of the leachate is greater than 11. Preferably, the pH value of the leaching solution is CaO and/or Na₂CO₃And (6) adjusting.

Preferably, the calcination temperature is 600-750 ℃, preferably 700 ℃.

Preferably, the leaching additive is added to the arsenic-containing gold concentrate before roasting.

Preferably, the leaching additives are NaOH and Na₂A mixture of S.

Preferably, the order of firing and grinding is interchanged.

In a preferred embodiment of the present invention, in the step (4), the acidity regulator is sulfuric acid.

Preferably, in the step (4), after the acidity regulator is added and before the complexing agent is added, air and Fe are simultaneously injected into the cyanogen slag³⁺Ions.

More preferably, in the step (4), after the acidity regulator is added and before the complexing agent is added, Fe is added to the cyanogen slag³⁺Ions and continuously injecting air into the leaching solution in the leaching process.

Particularly preferably, the pH is adjusted to 4 to 6, preferably 5, using an acidity regulator.

Air and Fe when the pH of the aqueous solution is low³⁺The leaching effect of gold is reduced when the ions cannot be effectively used As an oxidizing agent in the dissolution of cyanide slag, and conversely, when the pH value is higher, other optimized elements such As Pb and As are likely to be also includedAnd (4) leaching in a large amount.

Preferably, the air may be injected through the outside.

Preferably, the Fe³⁺The ions are added in the form of metal salts, such as sulfates.

Preferably, in step (4), in the leaching stage, Fe³⁺The ion concentration is 0.1-0.5 wt.%, preferably 0.3 wt.%.

In a preferred or alternative embodiment, in step (4), air is injected into the Fe-containing solution after the acidity regulator is added and before the complexing agent is added³⁺Ion solution, and then adding the solution to the cyanogenic slag.

When only Fe is added³⁺On ionization, the leaching rate of gold increases initially, with the potential of the solution increasing, thereby greatly increasing Fe³⁺The consumption of (c). However, when air is injected, oxygen in the air can be dissolved in the leaching residue solution, so that the leaching effect of gold is improved, and Fe is reduced³⁺The consumption of (c).

Preferably, the injection rate of air is 200ml/min-600ml/min, and if the injection rate is less than 200ml/min, the gold leaching rate is reduced to below 82%, and when the injection rate is higher than 600ml/min, undesirable leaching of Cu may be caused.

Preferably, the concentration of the complexing agent in the leaching system (typically referred to as the leach solution during leaching) is between 0.01 and 0.2mol/L, more preferably between 0.02 and 0.1 mol/L.

In a particularly preferred embodiment, the complexing agent is a compound of formula (I):

the compounds have a hydrophobic tail and a head that is easily protonated, thus enabling the formation of micellar structures in the leach solution. The Au ions lack the hydrophobicity possessed by the complex organic ligands, particularly in the case of hydrophobic ligands, and therefore they can concentrate on the surface of the micelles formed by the complex in the leaching solution only if they are oppositely chargedAnd thus helps electrostatic attraction. The gold charge and the complexing agent surface charge play a crucial role in altering the kinetics and the equilibrium of the reactions involving the metal ions. Because the gold particles are initially in the form of negatively charged complexes of AuCl^- ₄The surface charge properties of the complexing agent are very important for the leaching of gold ions.

Preferably, to enhance micelle formation even further, a surfactant, such as sodium dodecyl sulfate, may be added.

The compound shown in the formula (I) has a bidentate coupling-containing structure, can form a positively charged structure shown in the following formula (II), can transfer gold ions from water to a micelle phase, and has the yield close to 98%. Researches find that gold is difficult to strip from the surface of the micelle even if strong acid is added, so that the phenomenon of gold robbing is effectively avoided. In this compound, -N ═ N-remains unprotonated. It is expected that micelles of the positively charged complexing agent will induce an acceleration of the complex formation process.

It has also been found that the best results are obtained when sodium salts are present in the system, in particular using a mixture of ammonia and sodium salts, such as sodium chloride, in which the reduction of the surface potential caused by the salts and the complexing capacity of the nitrogen act in a uniform direction. The sodium salt may be derived from the leaching additive in step (2). Of course, sodium chloride may also be added additionally. Preferably, the concentration of sodium chloride in the leaching system is 0.05-0.2 mol/L.

Meanwhile, due to the hydrophobicity of the compound, the excellent gold extraction rate is ensured. Namely, the adsorption force of the Au complex on the surface of the micelle is stronger due to the combined action of the hydrophobicity and the charge, and the two directions are both in the direction of increasing the retention direction of the Au-complex on the colloid, so that the particularly good Au (III)/Cu (II) separation value is obtained, and the leaching rate and the leaching selectivity of Au are improved.

Detailed Description

The following are specific examples and comparative examples illustrating the present invention, but the present invention is not limited thereto.