A method for the enrichment and recovery of gold from zinc concentrates

Abstract

The present application relates to a kind of method for enriching and recovering gold from zinc concentrate, belong to zinc smelting technical field.The technical scheme of the present application includes: by being into secondary zinc material and control roasting temperature in zinc concentrate, make gold in zinc concentrate volatilize into high silver calcine, and high silver calcine is separately collected and leaching, so that gold enters silver concentrate and can be recycled and utilized.The present application can enrich and recover the gold with very low content in zinc concentrate, on the existing zinc concentrate processing process, without changing the normal recovery process of zinc, only increase the leaching of high silver gold calcine.The present application makes the gold in zinc concentrate have recovery value on the existing zinc concentrate processing process, and can be recycled, improves the resource utilization of zinc concentrate, increases the economic benefit of enterprise.

Description

Technical Field

[0001] This invention belongs to the field of zinc smelting technology, specifically, it relates to the enrichment and recovery of gold from zinc concentrate. Background Technology

[0002] Zinc concentrate contains trace amounts of gold. The gold content in zinc concentrate is typically below 1 g / t (market price), sometimes even below 0.1 g / t, resulting in high recovery costs and low recovery value. Current zinc concentrate processing methods involve roasting and desulfurization to produce roasted zinc ore, which is then leached to extract zinc, producing leaching residue. The leaching residue yield is only 35-45% of the zinc concentrate, and its gold content is far below 1 g / t, also lacking recovery value. Therefore, gold recovery from zinc concentrate has not received sufficient attention or emphasis from zinc smelting companies.

[0003] The leaching residue is either processed in a rotary kiln after silver flotation or directly fed into a fuming furnace. Regardless of whether the leaching residue is processed via flotation and a rotary kiln or directly into a fuming furnace, the gold content in the leaching residue is far below 1 g / t. This gold will not enter the silver concentrate during silver flotation, nor will it enter the zinc oxide dust during rotary kiln or fuming furnace processing. The gold in the zinc concentrate is ultimately lost in the rotary kiln slag or the water-quenched slag from the fuming furnace, resulting not only in resource waste but also negatively impacting the economic benefits of zinc smelting enterprises. Summary of the Invention

[0004] To overcome the problems existing in the background technology, the present invention provides a method for enriching and recovering gold from zinc concentrate. By adding secondary zinc material to the zinc concentrate and controlling the roasting temperature, the gold in the zinc concentrate volatilizes into the roasting dust, and the gold content in the roasting dust is greater than 1g / t, which has recovery value. After collecting and leaching the gold-containing roasting dust, the gold enters the silver concentrate, and the gold content in the silver concentrate is further increased, so that the gold in the silver concentrate can be recovered without affecting the leaching of zinc and the recovery of silver.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: The process of enriching and recovering gold from zinc concentrate includes the following steps: (1) Add secondary zinc materials to zinc concentrate and roast; (2) Collect high-silver gold-containing baking dust from the zinc roasting system to recover gold.

[0006] Preferably, the secondary zinc material mentioned in step (1) is zinc slag or blast furnace zinc ash.

[0007] Preferably, the high silver gold-containing baking dust mentioned in step (2) is electric field dust, or a combination of electric field dust and dicyclone dust.

[0008] As a preferred option, the mass ratio of the secondary zinc material to the zinc concentrate in step (1) is 2-10:100.

[0009] Preferably, in step (1), the roasting temperature of the zinc concentrate is 960-1050℃.

[0010] As a preferred method, the high silver content gold-bearing roasted dust is leached, and after liquid-solid separation, silver concentrate is obtained, with gold entering the silver concentrate.

[0011] Further optimization revealed that the leaching conditions for high-silver gold-containing baking dust were as follows: leaching temperature 70-90℃, leaching time 1-4h, and leaching endpoint acidity 0.005-100g / L.

[0012] As a preferred option, silver concentrate is fed into the crude lead smelting unit to recover gold and silver.

[0013] The beneficial effects of this invention are: This invention involves adding secondary zinc materials to zinc concentrate and controlling the roasting temperature. This causes gold in the zinc concentrate to volatilize and enter the electric field dust, resulting in high-gold-content electric field dust. By collecting and leaching the electric field dust and secondary vortex dust, the gold is allowed to enter the silver concentrate for recovery. This invention can enrich and recover extremely low levels of gold from zinc concentrate without affecting the recovery of zinc and silver. Furthermore, it does not require changes to the existing zinc concentrate processing flow; only the leaching of high-silver-content gold roasting dust needs to be added. This invention, by adding a recovery value to existing zinc concentrate processing technology, enables the recovery of gold, improves the resource utilization of zinc concentrate, and increases the economic benefits for enterprises. Attached Figure Description

[0014] Figure 1 This is a simplified process flow diagram of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0016] The method for enriching and recovering gold from zinc concentrate includes the following steps: (1) Ingredient preparation and roasting Secondary zinc materials are added to the zinc concentrate; the roasting temperature is controlled at 960-1050℃ to allow gold to volatilize and enter the roasting dust.

[0017] After zinc concentrate is roasted, the resulting roasting dust includes boiler dust, primary vortex dust, secondary vortex dust, and electric field dust. The yield of each type of roasting dust decreases from highest to lowest, with electric field dust having the lowest yield, followed by secondary vortex dust. The inventors discovered that gold is enriched in electric field dust. By adding a certain proportion of secondary zinc material to the zinc concentrate and increasing the roasting temperature of the zinc concentrate to 960-1050℃, gold in the zinc concentrate will volatilize into the electric field dust. Extensive experiments and analyses have shown that both the addition of secondary zinc material and the increase in roasting temperature are indispensable; otherwise, the amount of gold volatilized into the electric field dust will decrease.

[0018] The secondary zinc material added to the zinc concentrate is blast furnace zinc ash or zinc slag. Blast furnace zinc ash is dust collected from blast furnaces in iron and steel enterprises, containing Zn 15-30%wt, Fe 20-30%wt, SiO2 3-6%wt, Cl 3-10%wt, and Cd 0.2-0.6%wt. Zinc slag is slag produced by zinc smelting enterprises during the casting of zinc ingots or the production of zinc alloys, containing Zn 70-80%wt, Al2O3 4-6%wt, Cl 2-4%wt, and Fe 0.1-0.3%wt.

[0019] Extensive production practice has confirmed that when the proportion of secondary zinc material is less than 2 wt%, the amount of gold-in-the-field dust in the zinc concentrate decreases; however, when the proportion of secondary zinc material is greater than 10%, the amount of gold-in-the-field dust in the zinc concentrate no longer increases and will adversely affect the roasting dust collection system and waste acid treatment. Therefore, the mass ratio of secondary zinc material to zinc concentrate should be controlled at 2-10:100.

[0020] (2) Collection of gold-bearing roasting dust The electric field dust with high gold and silver content is collected separately. The vortex dust does not contain gold but has a high silver content. Since gold and silver can be recovered at the same time, in order to save process steps, the electric field dust and the vortex dust can also be collected together to obtain high silver and gold content roasted dust. The high silver and gold content roasted dust is processed together and gold and silver are recovered.

[0021] Boiler dust and roasted sand are ball-milled and then mixed with primary vortex dust to obtain low-silver, gold-free roasted ore. If the high-silver-content and gold-containing electric field dust is not collected separately, or if the electric field dust and secondary vortex dust are collected together, but instead mixed into the roasted ore, the large amount of roasted ore will dilute the gold in the electric field dust, making the gold content in the roasted ore much less than 1 g / t. In this case, gold cannot be enriched during the roasting of zinc concentrate.

[0022] (3) Gold-containing roasting dust leach out separately The high silver-containing gold-bearing roasted dust from step (2) is leached separately and then separated into liquid and solid to obtain silver concentrate. The leaching conditions are: leaching temperature 70-90℃, leaching time 1-4h, leaching endpoint acidity 10-100g / L, and the leaching residue after liquid-solid separation is silver concentrate. Gold and silver enter the silver concentrate, and the silver concentrate is fed into the crude lead smelting unit to recover gold and silver.

[0023] If the electric field dust is not leached separately but is mixed into the roasted ore, the gold content will be greatly reduced in the leaching residue of the roasted ore, losing its recycling value and ultimately being lost in the rotary kiln slag or the water-quenched slag of the fuming furnace.

[0024] Step (1) involves adding zinc-containing materials and controlling the roasting temperature to allow gold in the zinc concentrate to volatilize and enter the electric field dust; Step (2) involves collecting the gold-containing electric field dust separately or together with the cyclone dust to enrich the gold in the zinc concentrate; Step (3) involves leaching the gold-containing roasting dust separately to further enrich the gold and allow it to be recovered. The three implementation steps are interconnected, and the purpose of this invention cannot be achieved without any of the implementation steps.

[0025] To illustrate the present invention more clearly, the following embodiments will be described in detail. Example 1

[0026] Blast furnace zinc ash and zinc concentrate were mixed at a mass ratio of 2:100 and then fed into a roasting furnace for desulfurization. The roasting temperature was controlled at 1050℃. Electric field dust was collected separately. The composition of the electric field dust (%wt) was: Zn 40.06, Fe 7.61, Ag 1020g / t, Au 2.6g / t.

[0027] The electric field dust was leached separately under the following conditions: leaching temperature 70℃, leaching time 1.0h, and final acidity of 0.005g / L (pH 4.0). After liquid-solid separation, a gold-silver concentrate was obtained with a silver concentrate yield of 32.32%. The main components of the silver concentrate (%wt) were: Zn 18.89, Fe 23.36, Ag 3120g / t, Au 8.1g / t. All the silver and gold in the high-silver-gold-bearing roasted dust were enriched in the silver concentrate. The silver concentrate was then fed into the crude lead smelting unit to recover gold and silver.

[0028] Comparative Example 1

[0029] The same zinc concentrate as in Example 1 was used, without the addition of secondary zinc materials. The roasting temperature was the same as in Example 1. The electric field dust was collected separately. The composition of the electric field dust (%wt) was: Zn 40.51, Fe 7.46, Ag 1010 g / t, Au 1.4 g / t.

[0030] As can be seen from Comparative Example 1, the content of gold in the electric field dust decreased by 46.15% when secondary zinc material was not added. Example 2

[0031] Zinc slag and zinc concentrate were mixed at a mass ratio of 10:100 and then fed into a roasting furnace for desulfurization. The roasting temperature was controlled at 960℃. Electric field dust and cyclone dust were collected together to obtain high silver gold-containing roasting dust. The composition of high silver gold-containing roasting dust (%wt) is: Zn 44.13, Fe 9.01, Ag 760g / t, Au 1.4g / t.

[0032] The high-silver-gold-bearing roasted dust was leached under the following conditions: leaching temperature 90℃, leaching time 4.0 h, and final acidity 100 g / L. After liquid-solid separation, a gold-silver concentrate was obtained, with a silver concentrate yield of 19.21%. The main components of the silver concentrate (%wt) were: Zn 9.39, Fe 12.22, Ag 3950 g / t, Au 7.2 g / t. All the silver and gold in the high-silver-gold-bearing roasted dust were enriched in the silver concentrate. The silver concentrate was then fed into the crude lead smelting unit to recover gold and silver.

[0033] Comparative Example 2

[0034] Using the zinc slag and zinc concentrate from Example 2, and according to the technical conditions of Example 2, the roasting temperature was controlled at 900℃. The electric field dust and the vortex dust were collected together to obtain roasting dust. The roasting dust composition (%wt) was: Zn 47.31, Fe 9.92, Ag 490g / t, Au 0.5g / t.

[0035] As can be seen from Comparative Example 2, when secondary zinc material was added but the roasting temperature was reduced, the gold content in the electric field dust decreased by 64.28%, and the volatilization rate of silver also decreased. Example 3

[0036] Zinc slag and zinc concentrate were mixed at a mass ratio of 6:100 and then fed into a roasting furnace for desulfurization. The roasting temperature was controlled at 1000℃. Electric field dust and cyclone dust were collected together to obtain gold-containing roasting dust. The composition of the gold-containing roasting dust (%wt) was: Zn 45.63, Fe 9.43, Ag 740g / t, Au 1.3g / t.

[0037] The gold-bearing roasted dust was leached under the following conditions: leaching temperature 80℃, leaching time 2.5h, and final acidity 50g / L. After liquid-solid separation, a gold-silver concentrate was obtained, with a silver concentrate yield of 23.42%. The main components of the silver concentrate (%wt) were: Zn 11.19, Fe 15.48, Ag 3160g / t, Au 5.5g / t. All the silver and gold in the gold-bearing roasted dust were enriched in the silver concentrate. The silver concentrate was then fed into the crude lead smelting unit to recover gold and silver.

[0038] Comparative Example 3

[0039] The zinc slag and zinc concentrate from Example 3 were used, and the feedstock was prepared according to the technical conditions of Example 3. The roasting temperature was also the same as in Example 2. Electric field dust and secondary vortex dust were not collected separately, but were mixed with boiler dust and primary vortex dust into the roasted ore to obtain roasted ore. The composition of the roasted ore (%wt) was: Zn 58.64, Fe 10.60, Ag 210 g / t, Au < 0.1 g / t. Gold in the roasted ore lost its recovery value.

[0040] As can be seen from Comparative Example 3, even with the addition of secondary zinc materials to the zinc concentrate and control of the roasting temperature to facilitate gold volatilization, if the electric field dust or electric field dust and vortex dust are not collected separately, but instead mixed into the roasted ore to produce roasted ore, the large quantity of roasted ore will further dilute the gold already enriched in the electric field dust, making gold recovery impossible. Therefore, separate collection and separate leaching of gold-bearing roasted dust are crucial.

[0041] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for enriching and recovering gold from zinc concentrate, characterized in that, Includes the following steps: (1) Add secondary zinc materials to zinc concentrate and roast; (2) Collect high-silver gold-containing roasting dust from the zinc roasting system to recover gold; Among them, the secondary zinc material mentioned in step (1) is zinc slag or blast furnace zinc ash, and the roasting temperature is 960-1050℃; The high silver gold-containing baking dust mentioned in step (2) is electric field dust, or a combination of electric field dust and dicyclone dust.

2. The method according to claim 1, characterized in that, In step (1), the mass ratio of the secondary zinc material to the zinc concentrate is 2-10:

100.

3. The method according to claim 1, characterized in that, The method for recovering gold from high-gold and silver roasting dust is to leach the high-silver gold-containing roasting dust, separate the liquid and solid phases to obtain silver concentrate, and then the gold enters the silver concentrate.

4. The method according to claim 3, characterized in that, The leaching conditions are: leaching temperature 70-90℃, leaching time 1-4h, and leaching endpoint acidity 0.005-100g / L.

5. The method according to claim 3 or 4, characterized in that, Silver concentrate is fed into the crude lead smelting unit to recover gold and silver.

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