gold purity machine is suitable for refining gold with purity of 90% or higher. The company currently offers standard models such as JQ-JDJ-5, JQ-JDJ-10, JQ-JDJ-20, JQ-JDJ-30, and JQ-JDJ-50, capable of producing up to 50kg of gold per day. Custom orders based on client requirements can be arranged.

The company's ggold purity machine features an integrated, one-piece design, comprising individual electrolytic cells, circulation pumps, isolated power supplies, automatic electrolyte replenishment systems, smoke gas condensing recovery systems, intelligent monitoring systems for electrolyte temperature, voltage, current, and copper plate temperature, as well as data recording systems. The power supply is separately encapsulated and isolated from the plant's acid gases to ensure a long service life.

For rough gold with a gold content of less than 95%, initial treatment involves powdering. After powdering, the powdered gold is subjected to acid leaching using nitric acid to remove impurities such as silver and copper. The filtered solution is then processed for silver recovery. The insoluble gold powder undergoes aqua regia dissolution; insoluble residues from this process are subsequently sent for silver recovery. A secondary refining process is applied, where once reduced, 99.99% pure gold is cast into granules or ingots. The refined gold returns to the aqua regia process for further dissolution. After drying, the refined gold is formed into granules and then cast into standard gold ingots.

For raw materials with a gold content of 95% or higher, they can be directly smelted in a medium-frequency furnace, cast into ingots, and then subjected to high-efficiency electrorefining using a gold refining electrolysis system. The refined gold is then cleaned, dried, and finally cast into finished gold ingots.

(1) Dissolve in aqua regia:The residues are placed in a reaction container, and hydrochloric acid (HCl) and nitric acid (HNO3) are added in a 3:1 ratio by mass. The mixture is heated to a temperature between 60°C and 80°C using steam, allowing gold and platinum to dissolve in the solution. After the reaction is complete, the solution is filtered and washed, with the filtrate being sent for platinum extraction.

(2) Based on the differences in the reaction processes of platinum and gold, a separation is performed:Ammonium chloride (NH4Cl) is added to the filtered solution to precipitate platinum, while gold does not form a precipitate at this stage. The solution is then filtered again, and the resulting ammonioplatinum chloride is calcined to produce crude platinum, which contains gold in a high-temperature solution that is then sent for gold reduction.

(1) Mercury and Palladium Add nitric acid to the alloy and stir, heat the solution to approximately 50°C, allowing mercury and palladium to dissolve. Filter the solution to obtain filtrate and residue. The residue contains gold and platinum, which are then fed into the precious metal refining process.

(2) Silver Deposition Add hydrochloric acid to the solution in the reaction container to form silver chloride precipitate. Filter the solution to obtain silver chloride powder and palladium-containing solution. Process the silver chloride for precious metal recovery, while the palladium-containing solution is processed for palladium recovery.

(3) Replacement Add silver chloride to the reaction container and dissolve it in water. Add iron powder for replacement. Filter the solution. The residue is coarse silver powder.

(4) Palladium Oxidation Transfer the palladium-containing solution into a reactor, add 10% sodium chlorate solution for oxidation. After 1-2 hours of oxidation, add ammonium chloride to precipitate palladium. Filter after the reaction is complete and transfer the filtrate to the replacement unit.

Palladium Refining Process: 

1) Palladium Refining 

① Complex Dissolution Transfer ammonium palladium chloride into the refining process. Add an appropriate amount of water for solvation. Add ammonia for complexation, heating the solution to 80°C during this step. Filter after dissolution.

② Acidification and Precipitation Transfer the complex solution to a reactor, slowly add hydrochloric acid for acidification. Filter after reaction completion, transferring the filtrate to the replacement unit.

③ Reduction by Ammonia After two complexations and acidifications, perform a third complexation. Add prepared ammonium water solution (80%) in the ratio of 1 kg palladium to 1 Lammonium water. Slowly add the yellow powder solution, heat to boiling, stir thoroughly until the solution is completely reduced. Filter and wash the residue. The filtrate is sent to the replacement unit, while the residue becomes palladium sponge.

Precious Metals Recovery From E-waste Containing Gold And Palladium

Pre-Treatment With Fire:

(1) Roasting

The raw materials, such as gold-silver-platinum-iridium diodes and capacitors, are placed into the roasting kiln and rapidly heated to 600°C. The temperature is controlled within a range of approximately 600~800°C to ensure stable decomposition and vaporization of the materials in the kiln. This stage typically takes about 4~6 hours. After roasting, the products are crushed into smaller particles.

(2) Crushing

The roasted products are bulky, which could hinder subsequent precious metal recovery. The roasted products are therefore ground into fine granular materials before being sent to the wet recycling process.

After roasting, the products are fed into a crusher to break them into smaller pieces. These pieces are then transferred to the ball mill for further processing.

(3) Ball Milling and Sieving

The crushed pieces undergo ball milling to reduce their particle size further. The larger particles from the sieve are sent back to the ball mill for reprocessing, while the finer particles are forwarded to the wet recycling process.

1、Circuit Board Crusher: Breaks the circuit board to crush into pieces 2-3 cm in length.

2、Circuit Board Mill: Pulverizes the crushed circuit boards into particles around 20 mesh.

3、Analyzer: Conducts wind selection on the milled materials, separating resins, copper, dust, and fibers. Dust and fibers are collected by a fan into the collection tank, while resins and copper are fed into the sizing system. 

4、Collection Tank: Collects the dust and fibers. Fibers after collection are discharged for disposal.

5、Pulse Cleaner: Collects the dust and fine fibers generated during the breaking process.

6、Sieve: Separates resins and copper. If they do not separate properly, they are returned to the main unit for further milling; separated resins and copper are then fed into the density separation system for sorting.

7、Density Separator: Uses a separation method that takes advantage of the weight difference between copper and resin. Since copper is heavier than resin, it is separated from the other materials, achieving a separation rate of over 99%. This is currently one of the most advanced technologies in the country.

8、High-Voltage Static Separator: Further processes the residues from the density separator using high-voltage static electricity to separate fine copper powder and resins (the principle involves applying high voltage through a transformer to create a magnetic field, which attracts and separates conductive materials like copper).

State of Raw Materials and Products:

raw material：Monthly processing capacity: 50 tons of PCB board. Requirements include circuit board desoldering and powderizing leadframe, as well as separation of electronic components.

product:

1、National standard 1# gold;

2、Sponge platinum (≥99.95% purity);

3、Sponge palladium (≥99.95% purity);

4、Rough copper;

5、Resin.

design scheme:

This project processes PCB board scrap through physical and chemical methods to extract and refine precious metal products in accordance with national standards. The precious metal extraction should use simple, mature, and reliable processing methods as much as possible to achieve functional reliability, economic rationality, and management convenience; based on the product positioning of the client's products, combined with our company's precious metal refining and purifying equipment engineering application practice, the initial technical flowchart of the project is as follows.

Methods of Silver-concentrate Extraction:
Silver refining is often conducted in cyano and thiosulfate solutions, while the use of HCl and HNO3 for silver leaching is limited. In HCl solution, silver primarily exists as AgCl, forming precipitates under high chloride concentrations. Thus, precipitation methods are commonly used to recover silver rather than leaching methods.
In HNO3 solution, silver mainly exists as AgNO3 with a higher solubility. However, nitric acid acts as a strong oxidizer, which can degrade or age the leach solutions. For effective silver leaching, the leaching agents must possess good anti-oxidation properties. As a result, there are very few effective leaching agents for silver.
In cyano compounds, silver reacts similarly to gold, forming complexes like K3[Ag(CN)2]. These can be leached using appropriate cyanide-based leach solutions.
In thiosulfate-containing solutions, silver forms Ag(S₂O₃), which can be leached by specific reagents.

An electrolytic silver refining process in which crude silver is anodically dissolved and refined silver is cathodically deposited and at the same time accompanying metals are selectively extracted from the spent electrolyte and separately cathodically deposited after having been transferred into an aqueous phase and the regenerated electrolyte stripped of accompanying metals is recycled to the refining process and in which further the spent electrolyte is anodically enriched in silver and accompanying metals are cathodically deposited from the aqueous phase in a joint electrolysis step. 

The invention resides in that the joint electrolysis step is carried out in a diaphragm cell in which a diffusion zone is provided between one each cathode and one each anode and separated from the anode zone by an anionic separating membrane and from the cathode zone by a cationic separating membrane and that the diaphragm cell is charged via the diffusion zone with accompanying metal extract.