a method for recovering gold and silver from refractory gold ores, which falls into the field of metallurgy. It consists of two parts:

First, destroying the inclusions encapsulating gold and silver through hot pressure pre-oxidation, oxidizing organic carbon in the ore, and recovering sulfur contained in the ore;

Second, recovering gold and silver from the pre-leach residue via cyanidation or other cyanide-free leaching processes.

Recovery gold and silver from refractory gold ores, the total recovery rate of gold and silver exceeds 90%, which is 40 percentage points higher than that of the conventional cyanidation process, and the sulfur recovery rate is above 50% at the same time. The production cost of this process is approximately RMB 400 per ton of ore. Compared with bio-oxidation, two-stage roasting and conventional hot pressure oxidation processes,  can reduce investment and production cost, improve recovery efficiency, realize comprehensive recovery of multiple elements, and lower environmental pollution, with remarkable economic and social benefits.

At present, pretreatment methods for precious metal-bearing waste blue adhesive film sheets include the roasting process and wet stripping processes (using inorganic solvents and organic solvents respectively).

The roasting process has the advantage of a short treatment flow, as alloy feedstocks can be obtained directly after roasting. However, it has drawbacks of high investment cost: it requires the procurement of incinerators and flue gas treatment devices (as a large amount of harmful flue gas generated during roasting needs to be treated), leading to high environmental protection costs.

For the organic solvent-based wet stripping process, its merit is that it is easy to realize large-scale and automated production. Nevertheless, this method has defects such as long process flow, high requirements for production equipment, large reagent consumption, great harm to human health caused by the high volatility of reagents, and difficult waste liquid disposal.

As for the inorganic solvent-based wet stripping process, it also has problems including long treatment flow, low mechanization degree during the treatment process and relatively low efficiency.

The precious metal recovery electric arc furnace is a metal smelting furnace adopting DC (direct current) electric arc furnace technology, designed for the recovery and enrichment of precious metals from deactivated precious metal catalysts with silica-alumina carriers, precious metal-bearing tailings and smelting slag.

An openable curved exhaust hood is installed at the top of the furnace body. The hood consists of two symmetric left and right halves, which can be rotated towards each other to splice and form a hermetic seal. A screw conveyor is arranged above the furnace body, with its discharge port directly aligned with the furnace top. An exhaust duct is set above the opening-closing joint of the two halves of the curved exhaust hood, and the duct is connected in sequence to a dry quench tower, a bag dust collector, an induced draft fan and an exhaust stack.

Through material pretreatment and batching, the process improves the metal capture rate and the quality of the silicate glass phase in the furnace slag, making the slag meet the raw material standards for Portland cement and slag wool. It realizes the comprehensive recovery of both precious metals and catalyst carriers, and achieves the compliant disposal of hazardous solid waste.