Xinhai EPC Service of Gold Processing Scheme in Mali Africa 

Gold processing project in Mali Africa is an EPC service project. It was signed by the African customer and Xinhai group when he came to China to have an inspection. The customer was originally to use.. .method. But according to the ore dressing experiment done by Xinhai group customer, they finally think the complete mud cyaniding carbon plasma process is the best choice. The project is highly evaluated by the African customer. The following contents are early stages of processing plan which was done by Xinhai mining design institute and beneficiation research.

Firstly, basis of beneficiation scheme design

A, The relevant information and processing procedure collected in the field.

B, The agreed capacity: 1000 t/d.

C, The washability test report was given by Xinhai ore beneficiation research institute.

D, The other unknown conditions temporarily processed according to conventional processing procedure.

Secondly, the design scale, product and operation system

A, The new mill production scale is 1000 t/d, implements the system of continuous operation, lasting for300 days each year.

B, Ore dressing methods: Dump leaching the coarse grains and using the complete mud cyaniding carbon plasma method process the fine particles, finally using the gold wet smelting process.

C, Product program: 99.9% gold bullion.

Thirdly, the beneficiation test

The customer provide two ore samples, respectively defined as PY - 2 and PY - 3, PY - 2 ore sheet is coarse particles and PY - 3 ore sample is fine clay particles. Its small laboratory test. We draw the following conclusions by the contrast of different kinds of test schemes such as heap leaching, gravity separation and all mud cyanidation method.

The coarse ore PY-2 is suitable for heap leaching method to recovery gold. Undressed ore heap leaching use the sodium hydroxide to protect alkali with dosage of 8 kg/t; Dosage of sodium cyanide is 4 kg/t, heap leaching time is 168 hours, the leaching rate of gold is 88.55%.

The fine clay particles PY - 3 is suitable for the whole mud recycling gold cyanide solution. When grinding fineness of undressed ore cyanide is- 200 mesh and 82.88%, calcium oxide is used to protect the base, the amount of calcium oxide is 8 ~ 9 kg/t; The dosage of sodium cyanide is 1 kg/t, cyaniding for 24 hours and the leaching rate of gold is 88.00%.

According to the above data and the practical situation of the mine and site photo, Xinhai beneficiation research institute made the early stage of the project:

By screening and grinding cyanide heap leaching process to recovery gold, the undressed ore heap leaching method is used for the coarse grain and fine grinding one use the cyanide test method. After the separation of mine ore, use heap leaching method to process the coarse grain, the leaching rate of gold can be obtained at 66.67%.The fine one can be cyanided, and using 9.5 kg/t dosage of calcium oxide to protect alkali for 24 hours, the leaching rate of gold can be obtained at 85.57%. Total gold recovery rate is 85.17%. The following picture is the process engineering flow scheme for African Mali project made by Xinhai.

This process is the screening classification part, through a feeder the undressed ore were fed into the belt conveyor and then transported to the double layer vibrating screen for screening. Heap leaching the screened out + 30 mm and + 5 mm one, and the screened out- 5 mm one were classified by the cyclone classification machine firstly. After a period of grinding, the bottom flow of the cyclone together with the overflowed ones then go through the complete mud cyaniding carbon adsorption systems. According to the analysis of the core sample and the practical situation of the site, the heap leaching production is 1600 t/d, 10thousand ton for 2 months and all-slimed cyaniding is 2400 t/; Cyanide leaching analytic the electrolytic parts, and the - 60 mesh ones were transported to the leaching tank for leaching adsorption through the pum.

For heap leaching parts, through the steps of heap building, spray and expensive liquid adsorption, the gold mud was obtain by parsing and electrolyzing the gold-loaded carbon. For wed smelting parts, analytical electrolytic gold mud are  through the melting system regularly, and finally get the gold of 99.9%; For tailings parts, damming up the first years tailings plainly and backfilling the second year and the later tailings.

The design passed through the practice of the African clients inspection and achieved the expected index. The African client is very satisfied with that.

Through this project, Xinhai also won a good reputation in the African market.