CN1352310A

CN1352310A - Technological method for reextracting gold from cyanide gold refining wast slag

Info

Publication number: CN1352310A
Application number: CN 01134738
Authority: CN
Inventors: 李登新; 吕俊复; 岳光溪; 张建胜; 徐猛; 李玮琪
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2001-11-09
Filing date: 2001-11-09
Publication date: 2002-06-05
Anticipated expiration: 2021-11-09
Also published as: CN1172009C

Abstract

The present invention relates to metallurgical technology and technological process and features that gold is extracted from cyanide gold refining waste slag as material by means of catalytic oxidation process to leach gold wrapping mineral and the subsequent common cyanide gold refining process. The technological process is simple and can reach a gold extracting rate as high as 90 %. The present invention can reduce the harm of cyanide gold reinfing waste slag to environment while obtaining gold.

Description

Process for extracting gold again from cyaniding gold extraction waste residue

Technical Field

The invention relates to a gold extraction technology and a process, in particular to a process method for extracting gold by using cyanidation gold extraction waste residue as a raw material.

Background

In the prior art, waste residue produced by extracting gold by a common cyanidation method often contains a certain amount of gold, some of which are as high as 5g/t, and if the waste residue is subjected to a grinding process, a calcination process or an oxidation pretreatment cyanidation process, the leaching rate of the gold is only 10-60% (see the documents of nonferrous metal ores, No.5,2000, P11-14; Kuai Ming et al, Vol.342, No.12 and P21-22), the leaching rate of the gold is not high, and the process is complex and difficult to industrialize. In addition, some gold extraction cyanide slags contain high pyrite, chalcopyrite, galena and poisonous sand, and such slags are pulled by cement plants to be used as auxiliary materials, and release a large amount of poisonous gases such as sulfur dioxide, arsenic trioxide and the like due to high-temperature combustion; some of the materials are piled near a mine, so that spontaneous combustion is easily caused and air pollution is easily caused; meanwhile, harmful metal ions contained in the cyanogen slag are easy to flow into water or soil, if the cyanogen slag is not treated, environmental pollution is caused, and gold in the cyanogen slag is wasted, so that the cyanogen slag is required to be treated, and waste materials are changed into valuable materials.

Disclosure of Invention

The invention aims to provide a process method for extracting gold again by using cyanide gold extraction waste residue as a raw material, which can further improve the leaching rate of gold and fully extract residual gold in the waste residue on one hand, and can prevent the pollution of cyanide residue to the surrounding environment on the other hand, thereby changing waste into valuable.

The purpose and task of the invention are realized by the following technical scheme: the invention selects cyaniding gold extraction waste residue as raw material, firstly uses catalytic oxidation method to leach mineral matter wrapping gold in cyanide residue, then uses cyaniding gold extraction method to extract gold, the steps of the process method are as follows:

(1) pouring a certain amount of cyaniding gold extraction waste residue into an autoclave, uniformly mixing the cyaniding gold extraction waste residue with water, adjusting the pH value of the solution to be 1.0-3.0, adding a divalent or more compound of 0.01-5mol/L/L nitrogen into the solution as a catalyst, and uniformly stirring;

(2) then pressing air or oxygen into the reaction kettle by using a high-pressure pump, and stopping pressurizing when the pressure in the kettle reaches 4-100 atmospheric pressures;

(3) starting a stirrer to stir the mixture uniformly, heating the mixture, and reacting the mixture at the temperature of 30-180 ℃;

(4) after the reaction is finished, reducing the pressure of the reaction kettle to atmospheric pressure, and then filtering;

(5) neutralizing the filter residue with lime water to pH of 10-12, adding sodium cyanide, leaching gold at normal temperature and pressure, and extracting gold from the gold leaching solution by an electrolytic method.

In order to further reduce the cost, the catalytic oxidation filtrate is neutralized by alkali to ensure that the pH value is 1-3, and then the filtrate is recycled

In the above process, the catalyst for catalytic oxidation may be any one of sodium nitrate, potassium nitrate, ammonium nitrate and sodium nitrite.

The present invention uses cyaniding gold extracting waste residue as material, and utilizes catalytic oxidation process to leach out the mineral matter coating gold from the waste residue, and then utilizes common cyaniding process to leach out gold, and the extraction rate of gold can be up to above 90%. The process can obtain valuable gold, change waste into valuable, and reduce the harm of cyaniding gold extraction waste residue to environment.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The working principle and the embodiment of the invention are explained in detail as follows:

the process steps of extracting gold again by using cyanidation gold extraction waste residue are as follows: firstly testing the gold content in the cyanogen slag, if the gold content is more than 1g/t, leaching the mineral matter wrapping gold in the cyanogen slag by utilizing catalytic oxidation reaction, and then extracting the gold by utilizing a common cyanidation gold extraction method. The reaction mechanism is as follows:

because the cyaniding gold extraction waste residue generally contains pyrite, limonite, chalcopyrite, galena, poisonous sand and the like, the minerals often wrap gold, and the gold in the minerals cannot be extracted by the common cyaniding gold extraction method. The invention adopts a catalytic oxidation method, compounds with more than two-valent nitrogen such as nitric acid, sodium nitrate, potassium nitrate, ammonium nitrate, sodium nitrite, Nitrogen Oxide (NO) and other substances with certain oxidizability are used as catalysts, and the sulfide such as pyrite in the cyanogen slag can be oxidized into ferric sulfate, and the catalytic oxidation reaction is as follows:

the newly generated nitric acid and nitrous acid can react with pyrite, so that the minerals such as pyrite and the like in the cyanide slag are catalytically oxidized into ferric sulfate in the presence of air or oxygen, gold can be dissociated from the minerals, then sodium cyanide is added, the gold is leached at normal temperature and normal pressure, and the gold is extracted from the gold leaching solution by a conventional electrolytic method. In order to further reduce the cost, the catalytic oxidation filtrate is neutralized by alkali to enable the pH value to be 1-3, and then the catalytic oxidation filtrate can be recycled.

The reaction vessel used in the above process is required to be resistant to oxidation and acid.

Example (b):

example 1: putting 60% of cyaniding gold extraction waste residue containing 1g/t of gold into a reaction kettle, uniformly mixing the waste residue with 40% of water, then adding 5mol/L of catalyst nitric acid, and adjusting the pH value of the solution to 3.0; pressing air into the reaction kettle by using a high-pressure pump, wherein the pressure reaches 100 atmospheric pressures, and then heating the reactants to 30 ℃ for reaction for 4 hours; when the cyanide gold extraction waste residue is completely oxidized, filtering is carried out, the filter residue is neutralized to the pH value of 10 by lime water, then 2kg of sodium cyanide is added into each ton of cyanide residue, gold is extracted by using a common cyanidation method at normal temperature and normal pressure, and gold is extracted by using an electrolytic method from gold leaching liquid. The leaching rate of gold is as high as 90%.

Example 2:

30 percent of cyaniding gold extraction waste residue containing 5g/t of gold is put into a reaction kettle, 70 percent of water is added and evenly stirred, then 2mol/L of catalyst sodium nitrite is added, the PH value of the solution is adjusted to 2.0 by acid, air is pressed into the reaction kettle by a high-pressure pump, the pressure reaches 50 atm, and the reactant is heated to 120 ℃ for reaction for 8 hours. When the cyanide gold extraction waste residue is completely oxidized, filtering is carried out, the filter residue is neutralized to the PH value of 11 by lime water, then 4kg of sodium cyanide is added into each ton of cyanide residue, gold is extracted by using a common cyanidation method at normal temperature and normal pressure, and gold is extracted by using an electrolytic method from gold leaching liquid. The gold leaching rate is as high as 94%.

Example 3:

putting 10% of cyanidation gold extraction residue containing 3g/t gold into a reaction kettle, adding 90% of water, uniformly stirring, adding 0.01mol/L of ammonium nitrate serving as a catalyst, adjusting the pH value of the solution to 3.0 by using acid, pressing air into the reaction kettle by using a high-pressure pump until the pressure reaches 4 atmospheric pressures, heating the reactant to 180 ℃, and reacting for 8 hours. When cyanide gold extraction waste residue is completely oxidized, filtering to obtain reaction residue, neutralizing filter residue to pH value of 12 with lime water, adding 4kg sodium cyanide per ton of cyanide residue, leaching gold at normal temperature and normal pressure by using a common cyanide process, and extracting gold from the gold leaching solution by using an electrolytic process. The gold leaching rate is as high as 92%.

Claims

1. A process for extracting gold from cyanidation gold extraction waste residue, the method is characterized in that the cyanide gold extraction waste residue is used as raw material, the gold-coated minerals are leached by catalytic oxidation, and then gold is extracted by cyanide extraction Extract gold, the step of its process method is as follows:

(1). Pour a certain amount of cyanidation gold extraction waste residue into the autoclave, mix it with water evenly, and adjust the pH value of the solution to 1.0-3.0, and add 0.01-5mol/L nitrogen of more than two valences to the solution The compound is a catalyst and stirred evenly;

(2). Then use a high-pressure pump to press air or oxygen into the reactor, and stop pressurizing when the pressure in the reactor reaches 4-100 atmospheres;

(3). Start the mixer to stir the mixture evenly, turn on the heating system, and react at a temperature of 30-180°C for 4-10 hours;

(4). After the reaction is finished, reduce the pressure in the reactor to atmospheric pressure, and then filter;

(5). Neutralize the above filter residue with lime water to a pH value of 10-12, then add sodium cyanide, leach gold at normal temperature and pressure, and extract gold from the gold leaching solution by electrolysis.

2. according to claim 1, a kind of process of extracting gold with cyanidation gold extracting waste residue is characterized in that the filtrate filtered in the above-mentioned step (4) is neutralized with alkali, so that its pH value is 1～2. 3. Recycling.

3. according to claim 1 and 2 described a kind of processing method of extracting gold again with cyanidation gold extracting waste residue, it is characterized in that the catalyst that catalytic oxidation is used is any in sodium nitrate, potassium nitrate, ammonium nitrate, sodium nitrite A sort of.