CN106086417A - A kind of method extracting copper and gold from waste mobile phone circuit board - Google Patents

Abstract

The invention relates to a method for extracting copper and gold from waste mobile phone circuit boards, belonging to the field of resource recycling. At present, the main object for extracting metals in circuit boards is the computer main board, but there are few methods for extracting metals in mobile phone circuit boards. The method provided by this patent can solve this problem. At the same time, in view of the problems existing in the extraction of gold by the thiourea method in the past, the optimized parameters provided by this patent can solve this problem. This patent mainly completes the extraction of copper and gold through the two-step method of "nitric acid method-thiourea method", and high copper and gold leaching efficiency can be obtained through this method. The method can be used in resource recycling enterprises to process metals in circuit boards of waste mobile phones.

Description

A method for extracting copper and gold from waste mobile phone circuit boards

【Technical field】

The invention belongs to the field of resource circulation.

【Background technique】

At present, most of the research on metal extraction from waste circuit boards focuses on computer circuit boards, and there is less research on metal extraction from mobile phone circuit boards.

The methods for the extraction of metals in waste circuit boards mainly include: wet method, fire method, microbial method, and some emerging methods such as supercritical oxidation method. Among these methods, wet method is used more, because it is more effective for metals step by step. Extraction and recycling are relatively easy to implement and have relatively little impact on the environment.

Commonly used copper recovery methods in wet methods include: nitric acid method, sulfuric acid-hydrogen peroxide method, ferric chloride method, ammonia method, etc. Although the sulfuric acid-hydrogen peroxide method is relatively clean, it is relatively complicated; the ferric chloride method and the ammonia method have adverse effects on the leaching and recovery of gold afterwards; the nitric acid method is a simple, economical method, and will not affect subsequent processing.

Commonly used methods for recovering gold in wet methods include: cyanide method, aqua regia method, thiosulfate method, halogenation method, and thiourea method. Although the cyanidation method has a good leaching effect and has been used in metallurgy, it is a dangerous and highly toxic drug; the aqua regia method has high requirements for equipment due to its strong acidity and oxidative properties; the thiosulfate method and the halogenation method are due to Large reagent consumption or expensive reagents are not ideal; compared with other methods, thiourea method is non-toxic, has strong selectivity for gold, and high gold leaching efficiency. It is very promising to replace cyanide method, but thiourea itself has unstable The problem is that it is easy to decompose and produce impurities such as sulfur element, which will affect the continued leaching of gold. Aiming at this problem, this patent optimizes the parameters of the process of leaching gold with thiourea, which can solve the existing problems.

【Content of invention】

1. Technical problems to be solved:

The current processing technology mainly focuses on the extraction of metals from waste computer circuit boards, while waste mobile phone circuit boards are neglected due to their small size and difficulty in recycling. Technical problem of metal extraction in mobile phone circuit boards. At the same time, because of the instability of thiourea itself, the effect of thiourea extraction of gold is not ideal in the process of use. Therefore, it is necessary to study the optimal parameters of thiourea extraction of gold in mobile phone circuit boards.

2. Technical solution:

The first step is to react the sample with nitric acid to fully leach the copper and filter it. The filtered solution is reduced through the replacement reaction of zinc powder to obtain metallic copper, and the filter residue is fully dried for the next step of reaction. The reactions involved are as follows:

3Cu+8HNO ₃ →3Cu(NO ₃ ) ₂ +2NO+4H ₂ O

Cu+4HNO ₃ →Cu(NO ₃ ) ₂ +2NO ₂ +2H ₂ O

NaOH+HNO ₃ →NaNO ₃ +H ₂ O

Zn+Cu ²⁺ →Zn ²⁺ +Cu

Zn+H ₂ SO ₄ →ZnSO ₄ +H ₂ ↑

The second step is to carry out the reaction of extracting gold with thiourea on the dried filter residue. The filter residue reacts with thiourea and iron sulfate under acidic conditions to make gold form thiourea gold and dissolve in the solution, and then recover gold by electrolysis. The reactions involved are as follows:

Au+Fe ³⁺ +2SCN ₂ H ₄ →Au(SCN ₂ H ₄ ) ²⁺ +Fe ²⁺

The method for extracting copper and gold from waste mobile phone circuit boards in the present invention comprises preprocessing the waste mobile phone circuit boards to obtain sample 1 and performing wet extraction of copper; after filtering, the filtrate 1 is used to reduce copper, and the filter residue 1 is subjected to wet extraction of gold from the filter residue. The reacted solution was filtered, and the filtrate 2 was reduced to gold.

In the pretreatment, tools are used to manually remove the aluminum shell and resistance components on the surface of the waste mobile phone circuit board; the disassembled waste mobile phone circuit board is crushed, ground, and sieved to reach 20-200 meshes to obtain sample 1 .

In the wet extraction of copper, sample 1 is mixed with nitric acid solution in a reactor for reaction; the concentration of nitric acid is 4.5-5.5mol/L, the reaction time is 40-60min, the reaction temperature is 45-55°C, and the mass/volume of solid-liquid Ratio 1:15～1:25, stirring speed 300～400r/min; filter to obtain filtrate 1 and filter residue 1.

For the reduction of copper, adjust the pH of filtrate 1 to 1.5 with dilute NaOH solution, add excess zinc powder at a stirring speed of 300 to 400 r/min, and then remove excess zinc powder with dilute sulfuric acid solution. After the solution is filtered, the filter residue 2 Wash and dry to obtain reduced copper.

In the wet extraction of gold from the filter residue, the filter residue 1 is dried as a raw material for leaching gold, mixed with thiourea and ferric sulfate, and then reacted in a pH-adjusted solution; the reaction parameters are: thiourea concentration 9-15g /L, Fe3 ⁺ concentration 4~7g/L, reaction time 45~90min, reaction temperature 30~45℃, pH 1.5~3, stirring speed 300~400r/min, solid-liquid mass/volume ratio 1:20 ; Filter to obtain filtrate 2.

For the reduction of gold, the filtrate 2 is electrolyzed, and the gold deposited on the electrode is recovered.

3. advantages and positive effects of the present invention:

The invention has high leaching rate for copper and gold in waste mobile phone circuit boards, and high reduction rate for extracted metals.

【Description of drawings】

Figure 1 is a technical flow chart of extracting copper and gold in this technology.

【detailed description】

Example 1:

In nitric acid leaching copper step, adopt parameter: nitric acid concentration 4.5mol/L, reaction time 40min, reaction temperature 45 ℃, solid-liquid ratio (mass/volume) 1:15, stirring speed 400r/min, obtained 97.95% Copper leaching rate.

Example 2:

In nitric acid leaching copper step, adopt parameter: nitric acid concentration 5.5mol/L, reaction time 60min, reaction temperature 55 ℃, solid-liquid ratio (mass/volume) 1:25, stirring speed 400r/min, obtained 94.75% Copper leaching rate.

Example 3:

In thiourea leaching gold step, adopt parameter: thiourea concentration 9g/L, ^Fe Concentration 4g/L, reaction times 45min, 30 ℃ of reaction temperatures, pH is 1.5, stirring speed 400r/min, solid-liquid ratio ( Mass/volume) 1:20, obtained 95.88% gold leaching rate.

Example 4:

In thiourea leaching gold step, adopt parameter: thiourea concentration 15g/L, ^Fe Concentration 7g/L, reaction times 90min, 45 ℃ of reaction temperatures, pH is 3, stirring speed 400r/min, solid-liquid ratio ( Mass/volume) 1:20, obtained 96.61% gold leaching rate.

Claims (6)

1. from waste mobile phone circuit board, extract copper and a method for gold, waste mobile phone circuit board pretreatment is obtained sample 1 After carry out wet-milling processing；Filtering afterwards, filtrate 1 carries out going back native copper, and filtering residue 1 carries out filtering residue wet gold extraction, reacted solution mistake Filter, filtrate 2 reduces gold.

The method extracting copper and gold from waste mobile phone circuit board the most according to claim 1, it is characterised in that: described Pretreatment, uses instrument manual the removal aluminum hull of waste mobile phone circuit board surface, resistance element；To the waste mobile phone after disassembling Circuit board carries out crushing, grinding, and reaches 20～200 mesh, obtain sample 1 after sieving.

The method extracting copper and gold from waste mobile phone circuit board the most according to claim 1, it is characterised in that: described Wet-milling processing, is mixed in sample 1 in reactor with salpeter solution and reacts；Concentration of nitric acid 4.5～5.5mol/L, during reaction Between 40～60min, reaction temperature 45～55 DEG C, the mass/volume of solid-liquid is than 1:15～1:25, mixing speed 300～400r/ min；Filter, obtain filtrate 1, filtering residue 1.

The method extracting copper and gold from waste mobile phone circuit board the most according to claim 1, it is characterised in that: described Also native copper, by filtrate 1 with dilute NaOH solution regulation pH to 1.5, adds excess zinc under 300～400r/min mixing speeds Powder, removes unnecessary zinc powder with dilution heat of sulfuric acid afterwards, and after solution filters, filtering residue 2 washs, is dried to obtain and goes back native copper.

The method extracting copper and gold from waste mobile phone circuit board the most according to claim 1, it is characterised in that: described Filtering residue wet gold extraction, is dried the raw material as gold lixiviation using filtering residue 1, after it mixes with thiourea, iron sulfate, in regulating pH Solution in react；Response parameter is: thiourea concentration 9～15g/L, Fe3+ concentration 4～7g/L, the response time 45～90min, instead Answering temperature 30～45 DEG C, pH is 1.5～3, mixing speed 300～400r/min, and solid-liquid mass/volume is than for 1:20；Filter, To filtrate 2.

The method extracting copper and gold from waste mobile phone circuit board the most according to claim 1, it is characterised in that described Reduction gold, is electrolysed filtrate 2, and reclaims the gold being deposited on electrode.