阅读说明：本技术 一种难处理原生矿预处理及氰化提金的方法 (Method for pretreatment and cyaniding gold extraction of refractory crude ore ) 是由 王梅君 陈庆根 陈进松 简勇章 林海彬 邱耀兴 于 2020-08-03 设计创作，主要内容包括：本发明公开了一种难处理原生矿预处理及氰化提金的方法,包括如下步骤：原矿破碎、矿堆生物氧化；硫磺氧化；体系介质转化；矿堆氰化浸出；电解得到金锭。本发明相对于现有的生物氧化工艺,成本都大幅降低,具有经济优势,不仅节省药剂成本,同时增加了金属回收率,延长矿山的服务年限。(The invention discloses a method for pretreatment and cyaniding gold extraction of refractory original ore, which comprises the following steps: crushing raw ores and biologically oxidizing ore piles; oxidizing sulfur; converting a system medium; cyaniding and leaching the ore heap; electrolyzing to obtain gold ingots. Compared with the existing biological oxidation process, the method has the advantages of greatly reducing the cost, having economic advantages, saving the medicament cost, increasing the metal recovery rate and prolonging the service life of mines.)

1. A method for pretreatment and cyanidation gold extraction of refractory primary ore is characterized by comprising the following steps:

s1, mixing and stacking the industrial sulfuric acid and the ore sample obtained by crushing the raw ore;

s2, carrying out acid washing on the ore heap built in the step S1 by using a dilute sulfuric acid solution, feeding the acid-washed liquid into a washing water tank, supplementing acid to the acid-washed liquid in the washing water tank, returning to the acid washing until the pH value of the acid-washed liquid is less than 2.2, and then, connecting the acid-washed liquid into a bacteria liquid tank;

s3, carrying out biological oxidation on the ore heap after the acid washing in the step S2:

after the pH of the acid-washed liquid reaches 2.2, inoculating the bacterial liquid in the bacterial liquid pool into the ore heap, and starting biological oxidation; laying an inflation pipe at the bottom of the ore heap, wherein the inflation pipe is provided with an aeration hole; the gas filling pipe is connected with the low-pressure Roots blower and is used for filling gas into the ore heap;

s4, adding sulfur, raw ore powder and a culture medium into a primary oxidation tank according to mass percentage, mixing, and introducing air for oxidation; the primary oxidation tank and the secondary oxidation tank are connected in series, the mixture is oxidized in the primary oxidation tank and then enters the secondary oxidation tank for continuous oxidation, the finally obtained oxidation product enters the thickener, the underflow of the thickener returns to the primary oxidation tank for oxidation, the overflow of the thickener is accessed to the ore heap in the biological oxidation process for acidity adjustment in the biological oxidation process of the ore heap, and the pH of the effluent liquid of the ore heap is controlled to be less than 2.2; the heat generated by the primary oxidation tank and the secondary oxidation tank is used for heating the bacteria liquid in the bacteria liquid pool through heat exchange;

s5, converting a system medium:

washing the ore heap with tap water until the water washing liquid is weakly acidic, and allowing the water washing liquid to enter a water washing tank; after the ore heap is drained, the liquid in the washing pool and the bacteria liquid pool is respectively pumped into the washing pool and the bacteria liquid pool of the next ore heap, the bacteria liquid pool of the ore heap is changed into an alkali washing pool, and the washing pool is changed into a precious liquid pool; performing alkaline washing on the ore heap by using an alkaline solution prepared from lime until the pH of the effluent liquid of the ore heap is 10-11, and enabling the effluent liquid to enter an alkaline washing pool;

s6, ore heap cyaniding leaching:

dripping the ore heap by using a sodium cyanide solution with the mass concentration of 1 per thousand in the first 15 days, then dripping the ore heap by using a sodium cyanide solution with the mass concentration of 0.5 per thousand, allowing the obtained precious leaching solution to enter a precious solution pool, and returning to cyaniding and leaching after the precious leaching solution is adsorbed by activated carbon; ending cyaniding leaching after 180 days;

s7, after cyaniding leaching is finished, washing the ore heap with 4g/L NaOH until the concentration of NaCN in the liquid flowing out of the ore heap is below 10ppm, then spraying and washing with clean water until the pH value of the liquid flowing out of the ore heap is reduced to 6, and returning the obtained washing liquid to an alkali washing pool;

and S8, continuously producing to obtain leached pregnant solution, adsorbing by activated carbon, desorbing, and electrolyzing to obtain gold ingots.

2. The method as claimed in claim 1, wherein in step S1, the raw ore is crushed using three stages until the ore particle size reaches P80-12 mm.

3. The method according to claim 1, wherein in step S1, industrial sulfuric acid is mixed with an ore sample obtained by crushing raw ore at a weight ratio of 5kg/t and piled.

4. The method of claim 1, wherein in step S2, the acid-washed solution is pumped into the bacteria solution pool to supplement water to the bacteria solution pool, wherein the potential of the bacteria solution pool is controlled to be greater than 550mV during the supplement process, and the iron and the residual acid dissolved from the ore heap are used for bacterial culture during the supplement process.

5. The method of claim 1, wherein during the biological oxidation of the ore heap in step S3, the aeration is carried out 2-3 times a week for 1 hour each time, and the aeration biological oxidation time is 150 d.

6. The method according to claim 1, wherein in step S3, in the biological oxidation process of the ore heap, the liquid flowing out of the ore heap returns to the bacteria liquid pool, and then is connected to the ore heap again for recycling, after the biological oxidation is finished, the oxidized liquid in the bacteria liquid pool is neutralized by lime, the neutralized slag is discharged into a tailing pond, and the neutralized liquid is discharged or recycled.

7. The method as claimed in claim 1, wherein the primary and secondary oxidation tanks have an effective volume of 1800m in step S4³The flow velocity of the primary oxidation tank is 50m³H, flow rate of the secondary oxidation tank is 150m³And/h, the mixture stays in the primary oxidation tank for 36h, stays in the secondary oxidation tank for 12h, the total staying time is 2d, the sulfur oxidation rate is 45 percent, and the sulfuric acid concentration of the primary oxidation tank and the secondary oxidation tank is controlled to be less than 60 g/L.

8. The method of claim 1, wherein in step S4, 10% sulfur, 5% raw ore powder and 85% 9K culture medium are added to the primary oxidation tank by mass percentage.

9. The method as claimed in claim 8, wherein in step S4, the particle size of the raw ore powder is 74 μm or P80 ═ 74 μm.

10. The method of claim 1, wherein in step S6, the dripping speed is 8-12L/(m)²·h)。

Technical Field

The invention relates to the technical field of metallurgy, in particular to a method for pretreatment and cyaniding gold extraction of refractory primary ore.

Background

Gold is a rare and precious metal, not only used for special currency of storage and investment, but also an important material for departments of jewelry industry, electronic industry, modern communication, aerospace industry and the like.

In the process recovery, the gold ore which is difficult to be treated is usually floated to obtain refined gold ore, and the refined gold ore is pretreated by pressure oxidation, biological oxidation, roasting, superfine grinding and other processes, and then cyanided. However, the method has high equipment investment cost, and is difficult to economically recover a plurality of small gold ores, low-grade ores, tailings or waste rocks.

Currently, a biological oxidation heap leaching process is also adopted, and the process needs three steps of acid pretreatment, biological oxidation, system conversion and the like, so the acid consumption cost and the biological oxidation efficiency are the key of the process on economy and effectiveness. Direct oxidation of raw ore entails a considerable consumption of acid, and the heap bioleaching of deer dam gold in 1996 is forced to be discontinued for this reason.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for pretreatment and cyaniding gold extraction of untreated primary ore.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for pretreatment and cyanidation gold extraction of refractory primary ore comprises the following steps:

s1, mixing and stacking the industrial sulfuric acid and the ore sample obtained by crushing the raw ore;

s2, carrying out acid washing on the ore heap built in the step S1 by using a dilute sulfuric acid solution, feeding the acid-washed liquid into a washing water tank, supplementing acid to the acid-washed liquid in the washing water tank, returning to the acid washing until the pH value of the acid-washed liquid is less than 2.2, and then, connecting the acid-washed liquid into a bacteria liquid tank;

s3, carrying out biological oxidation on the ore heap after the acid washing in the step S2:

after the pH of the acid-washed liquid reaches 2.2, inoculating the bacterial liquid in the bacterial liquid pool into the ore heap, and starting biological oxidation; laying an inflation pipe at the bottom of the ore heap, wherein the inflation pipe is provided with an aeration hole; the gas filling pipe is connected with the low-pressure Roots blower and is used for filling gas into the ore heap;

s4, adding sulfur, raw ore powder and a culture medium into a primary oxidation tank according to mass percentage, mixing, and introducing air for oxidation; the primary oxidation tank and the secondary oxidation tank are connected in series, the mixture is oxidized in the primary oxidation tank and then enters the secondary oxidation tank for continuous oxidation, the finally obtained oxidation product enters the thickener, the underflow of the thickener returns to the primary oxidation tank for oxidation, the overflow of the thickener is accessed to the ore heap in the biological oxidation process for acidity adjustment in the biological oxidation process of the ore heap, and the pH of the effluent liquid of the ore heap is controlled to be less than 2.2; the heat generated by the primary oxidation tank and the secondary oxidation tank is used for heating the bacteria liquid in the bacteria liquid pool through heat exchange;

s5, converting a system medium:

washing the ore heap with tap water until the water washing liquid is weakly acidic, and allowing the water washing liquid to enter a water washing tank; after the ore heap is drained, the liquid in the washing pool and the bacteria liquid pool is respectively pumped into the washing pool and the bacteria liquid pool of the next ore heap, the bacteria liquid pool of the ore heap is changed into an alkali washing pool, and the washing pool is changed into a precious liquid pool; performing alkaline washing on the ore heap by using an alkaline solution prepared from lime until the pH of the effluent liquid of the ore heap is 10-11, and enabling the effluent liquid to enter an alkaline washing pool;

s6, ore heap cyaniding leaching:

dripping the ore heap by using a sodium cyanide solution with the mass concentration of 1 per thousand in the first 15 days, then dripping the ore heap by using a sodium cyanide solution with the mass concentration of 0.5 per thousand, allowing the obtained precious leaching solution to enter a precious solution pool, and returning to cyaniding and leaching after the precious leaching solution is adsorbed by activated carbon; ending cyaniding leaching after 180 days;

s7, after cyaniding leaching is finished, washing the ore heap with 4g/L NaOH until the concentration of NaCN in the liquid flowing out of the ore heap is below 10ppm, then spraying and washing with clean water until the pH value of the liquid flowing out of the ore heap is reduced to 6, and returning the obtained washing liquid to an alkali washing pool;

and S8, continuously producing to obtain leached pregnant solution, adsorbing by activated carbon, desorbing, and electrolyzing to obtain gold ingots.

Further, in step S1, the raw ore is crushed using three stages until the ore particle size reaches P80 ═ 12 mm.

Further, in step S1, industrial sulfuric acid and the ore sample obtained by crushing the raw ore are mixed at a weight ratio of 5kg/t and piled.

Further, in step S2, pumping the acid-washed solution into a solution pool to supplement water to the solution pool, wherein in the supplementing process, the potential of the solution pool is controlled to be greater than 550mV, and iron and residual acid dissolved from the ore heap are used for bacterial culture while supplementing water.

Further, in the process of biological oxidation of the ore heap in the step S3, 2-3 times of aeration are carried out for one week, 1 hour is carried out for each aeration, and the aeration biological oxidation time is 150 d.

Further, in step S3, in the biological oxidation process of the ore heap, the liquid flowing out of the ore heap returns to the bacteria liquid pool, and is then connected to the ore heap again for recycling, after the biological oxidation is finished, lime is used for neutralizing the oxidized liquid in the bacteria liquid pool, the neutralized slag is discharged into a tailing pond, and the neutralized liquid is discharged or recycled.

Further, in step S4, the effective volume of the primary oxidation tank and the secondary oxidation tank is 1800m³The flow velocity of the primary oxidation tank is 50m³H, flow rate of the secondary oxidation tank is 150m³And/h, the mixture stays in the primary oxidation tank for 36h, stays in the secondary oxidation tank for 12h, the total staying time is 2d, the sulfur oxidation rate is 45 percent, and the sulfuric acid concentration of the primary oxidation tank and the secondary oxidation tank is controlled to be less than 60 g/L.

Further, in step S4, 10% sulfur, 5% raw ore powder and 85% 9K medium by mass are added to the primary oxidation tank.

Further, in step S4, the particle size of the raw ore powder is P80 ═ 74 μm.

Further, in step S6, the dripping speed is 8-12L/(m)²·h)。

The invention has the beneficial effects that: compared with the existing biological oxidation process, the method has the advantages of greatly reducing the cost, having economic advantages, saving the medicament cost, increasing the metal recovery rate and prolonging the service life of mines.

Drawings

FIG. 1 is a flowchart of a method of example 1 of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, and it should be noted that the present embodiment is based on the technical solution, and the detailed implementation and the specific operation process are provided, but the protection scope of the present invention is not limited to the present embodiment.