Comprehensive recovery of gold and valuable metals from tailings

Recently our gold mines, tailings gold grade manufacturers in 0. 5g / t more than the number of them, especially those old mines in the early development of gold, due to technical immaturity, backward production technology, tailings gold grade more High, some even as high as 4g / t or more, while the tailings also contain a certain amount of other valuable metals. For these tailings, a suitable process can be used to recover gold and comprehensively recover a part of valuable metals. This not only makes full use of mineral resources, but also obtains good economic benefits. A gold mine in southern China, since 1955, has more than stockpiling tailings 350,000 t, where the average grade of gold, antimony, tungsten were 4.2g / t, 0.8%, 0.18 %, metal reserves were 1.473t, 2517t 569t. According to the nature of the old tailings, a series of experimental studies by the Changchun Gold Research Institute have shown that flotation and recovery of some of the gold in the old tailings should be carried out by flotation, and the flotation tailings should be cyanated and leached to recover gold. Since most of the plutonium in the old tailings has been oxidized, the recovery rate is not high when the flotation is recovered, and the remaining plutonium still affects the cyanidation leaching. The institute uses a kind of MNP oxidant to oxidize and pre-cyanide the flotation tailings, and then obtain good results. Finally, the cyanide tailings are reused for flotation to recover tungsten. The recovery rates of gold, antimony and tungsten reached 81.18%, 20.17% and 61.00%, respectively. According to the production scale of 100t/d, only the calculation of gold can generate an annual output value of 11.46 million yuan. After deducting the cost, at least a profit of 5.88 million yuan can be obtained every year. If you add the output value of tantalum and tungsten, the profit will increase. Lingbao County is the second largest gold production county in China. According to the data, many mines use amalgamation -flotation process. The average grade of tailings discharged per year is about 1.2g/t. The ore in this area is mainly composed of yellow iron. For the type of mine, gold is unevenly embedded in medium and fine grains, and natural gold accounts for 60.11% of the total gold. After Guangzhou Nonferrous Metal Research Institute of the three kinds of research process tailings area has been the recovery of gold were found in the residual gold tailings mainly pyrite with students, and some finely ground mineral processing plant because of the thick, golden load Iron ore does not dissociate from the monomer, thus affecting the recovery of gold. A tailings (average grade 0.74g/t) which has been dissociated from most of the gold-bearing iron ore, using hydraulic classification, +74μm product is treated by spiral-shaker re-election process, -74μm product is flotation Processed, 49.05% gold can be recovered.

Sheet Metal Fabrication

Sheet Metal Fabrication

Definition of sheet metal fabrication

Sheet Metal fabrication is the creation of useful metallic parts and structures by the application of multiple fabrication processes. Sheet metal fabrication is basically a broad term that involves various complex processes like cutting, forming, bending, welding, machining, and assembling. The instructions include below: materials, processes, and tools required for sheet metal fabrication.

Types of Sheet Metal Fabrication Materials

The choice of metal depends on the final use of the fabricated parts.

Common fabrication processes:

· Carbon Steel

· Stainless Steel

· Aluminum

· Bronze

· Copper

· Brass

· Aluminized steel

· Galvanized steel

Types of Metal Fabrication Processes

The journey to the final product from raw sheet metals proceeds through various sheet metal fabrication processes. All the sheet metal fabrication processes can be grouped into the following three categories:

· Cutting

· Deformation

· Assembly

Sheet metal fabrication: Cutting

i. Laser Cutting

ii. Water jet cutting

iii. Plasma cutting

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Sheet metal fabrication: Forming or Deformation

Bending: Sheet metal bending is one of the most popular deformation processes. A machine known as a Press brake is used to bend sheet metals into V, U, or other complex shapes. With an increase in gauge thicknesses of sheet metals the force required to bend increases.

Stamping: In the stamping process, a hydraulic or mechanical stamping press equipped with a tool and die is used to perform specific tasks like curling, drawing, embossing, flanging, etc

Hemming: Hemming is a process by which the edges of sheet metal are folded over itself or another piece of sheet metal to create a rounded edge. In the sheet metal fabrication process, two types of hemming processes are widely involved. They are roll hemming and conventional die hemming. Conventional hemming is used for mass production. A hemming roller is used for roll hemming.

Spinning: Spinning is a metal fabrication process where a lathe machine is used to rotate the sheet metal against a tool to produce conical or cylindrical shapes.

Sheet metal fabrication: Assembly

Assembly is basically joining sheet metal components produced using above mentioned cutting or bending processes. The common sheet metal assembly process consists of joining by Welding and joining using fasteners.

Welding: In the welding process, sheet metal components are joined together by melting sections with the application of heat to form a solid connection. There are various processes available that are used to weld sheet metals.

Joining using Fasteners: Similar or dissimilar sheet metal parts can easily be joined using fasteners like bolts, screws, rivets, etc.

Brazing: Brazing is a process similar to welding that operates by melting a filler without melting the sheet metals.

Adhesives: Adhesives can be used to hold metal sheets together in conjunction with other joining methods

Advantages and Disadvantages of Sheet Metal Fabrication

As sheet metal fabrication covers a wide area of techniques and methods, the advantages and limitations will vary depending on the process used during fabrication.

Benefits:

i. Sheet metal fabrication is fast and can produce high-quality components.

i. A large number of processes are available with wide range of materials

ii. High strength to weight ratio for sheet metal fabricated parts.

Disadvantage:

i. Each fabrication process has their own limitations.

ii. High initial cost for set up of equipment and tools.

iii. Requirement of skilled labors for each process.

Sheet Metal Fabrication,Custom Sheet Metal Fabrication,Precision Sheet Metal Fabrication,Stainless Steel Sheet Metal Fabrication

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