Can waste circuit boards be recycled?
When the filtrate is concentrated to silver nitrate, the crystallization of silver nitrate is transferred and filtered, and all the silver nitrate crystals are precipitated and absorbed. Finally, the silver nitrate is put into the dryer and dried to be used. If the purity of the silver nitrate is not high, multiple crystallization can be used to increase purity.
Silver is also one of precious metals. The recovery of silver from waste liquid is as follows:The waste liquid is adjusted by 20% sodium hydroxide, and the pH value is between 8-9. Then sodium sulfide solution is added to precipitate the silver sulfide;(1): +2Na+: 2Ag+Na2S==Ag2S(2) water washed silver sulfide precipitate to residual sulfide, filtered water, the silver sulfide in the crucible, heating to 800-900 DEG C for desulfurization, remove the cooling.(3) to 100 (weight) silver slag, add borax 10, sodium chloride 5 mix and then burning to crude silver crucible.
The waste circuit board can be recycled, the PCB circuit board plating waste liquid has greater recycling value, and the PCB circuit board plating waste liquid can be saved on the comprehensive utilization, and the cost can be saved and the cost can be reduced. The comprehensive utilization of PCB plating waste liquid is not only to reduce the losses caused by the discharge, but also is of great significance from the angle of preventing pollution and reducing the cost of sewage treatment.
