GB/T 36385-2018 in English

Waste liquid treatment and disposal process and methods

Metal replacement method is suitable for silver recovery of waste fixer solution, and metallic silver precipitate is generated by the reaction of active metals such as iron and aluminum with silver-containing solution. The process parameters include normal temperature and pressure, pH 4.0~6.5, and a roasting temperature of about 1100°C.

Electrolysis is also applicable to waste fixer solution, using direct current to precipitate silver ions at the cathode. The voltage is controlled at 2.0~3.0 V, pH 6.0~9.0, and the roasting temperature is the same as above.

Chemical precipitation is applicable to waste bleaching solution, adding sulfide ions or chloride ions to separate silver in the form of precipitation. The reaction conditions are normal temperature and pressure, pH 8.0~9.0, and using saturated sodium sulfide solution or sodium chloride solution.

Implementation recommendations

• Enterprises should choose appropriate silver recovery methods according to the type of waste liquid
• Regularly maintain production equipment to ensure the stability of process parameters
• Strengthen waste residue and tail gas treatment to ensure compliance with GB 16297 requirements