How do you recover precious metals from electronic waste?

Precious metals are widely used in many industrial fields due to their excellent corrosion resistance, good electrical conductivity and high catalytic activity. But its reserves are lower than global production. Fortunately, we can obtain them from other sources. Electronic waste (especially in waste circuit boards) is an important resource, which contains more than 90% of precious metals. Well, how do we recover precious metals from electronic waste?

Method 1: Fire treatment

Working process:

Fire treatment is the traditional way to recover precious metals from electronic waste. Firstly, we need to dismantle the circuit boards from other components (such as plastic casings, electronic components, etc.), by manual disassembly or mechanical equipment. Then Use crusher or pulverizer to crush the circuit boards into small particles. Next, put the pulverized circuit board into a high temperature furnace, taking advantage of high temperature and chemical reactions, to burn or decompose the organic and inorganic substance. The metals will melt and deposite on the bottom of the furnace. Last, using magnetic separator, air separator or flotation to separate the metals from other impurities.

Fire treatment

Pros and Cons:

It can effectively recover the precious metals in the circuit board. But it will do harm to environment, due to it will produces harmful gases and waste water. In addition, not all precious metals are completely recovered, which may be a certain waste. Most importantly, the cost is high.

Method 2: Chemical recovery

Working process:

The second method to recover precious metals from electronic waste is chemical recovery. Its first few process is same as fire treatment, to crush the waste circuit boards into small particles. Then dissolve the small particles in an acidic solution, such as sulfuric acid, hydrochloric acid, etc. to dissolve the metal elements to form metal ions. Next, adjust the pH value and temperature of the solution and add a precipitating agent, then the metal element will be precipitated out of the solution. At last, filter, wash and dry the precipitates, the metals will be separated.

Chemical recovery

Pros and Cons:

First of all, it adopts different dissolution and precipitation methods for different metal elements, thus, the recovery efficiency is high. In addition, compared with fire treatment, it is relatively simple to operate, has lower equipment requirements, and lower cost. However, it also has some disadvantages. For example, the acidic solution may pollute the environment. Besides, the acidic liquids are generally corrosive and have a high risk factor.

Method 3: Physical separation

Working process:

Physical separation usually refers to use waste circuit board recycling machine to recover precious metals from electronic waste. Its first few processes are also dismantling, shredding or crushing. After crushing, there will be an eddy-vibrating screen to control the size of particle. Only small enough particles can pass through the screen, those big particles will be stopped and sent back to the crushing for crushing completely. Then the air separator and electrostatic separator will separate the precious metals from non-metals.

Waste circuit board recycling machine

Pros and Cons:

Physical separation adopts dry type separation method, which won't produce any pollution to environment. Besides, the physical method won't damage the quality of metals, which can be sold in the market at a good price. The cost of physical separation is slightly higher, because different capacity has different cost.

DOING waste circuit board recycling machine has been popular exported to more than 100+ countries and regions, and well recognized by our customers due to the high separating rate, stable operation and meet different countries' standards. More machine details, please contact us. And our sales manager will recommended you suitable waste circuit board recycling machine to recover precious metals from electronic waste.