gold ore reselection process

reselection: Separates gold from most minerals.

parting: The concentrate obtained is refined further through methods like vaporization to increase gold content.

refining: The refined dore goes through wet processing to achieve higher purity.

gold ore flotation process:

Flotation Process: Separates gold from most minerals.

Cyanide dissolution and replacement: The rough gold obtained through cyanide dissolution is converted into gold mud.

Refining of gold mud: The wet processing of the placer gold to refine it further.

platinum group metal recovery rate high:

In the recycling process of platinum group metals (such as palladium), some palladium in certain processes is oxidized into inert oxides that are poorly soluble in acid or base. 

This, coupled with the stability and poor solubility in nitric acid of rhodium and iridium, results in low recovery rates for these precious metals. We designed a pretreatment process for such materials to effectively improve their leaching rates, thereby enhancing the overall recovery rate of valuable metals.

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).