Mineral processing of gold deposits

Sand gold ore beneficiation process principle is to maximize the recovery of gold from ore by gravity separation and its associated various heavy minerals, and then re-election, flotation, amalgamation, electrostatic and magnetic separation operations will jointly selected from Gold and various heavy minerals are separated from each other and have achieved the purpose of comprehensive recovery. The classification of gold deposits is generally divided into processes such as crushing and screening, desliming and sorting.

First, crushing and screening

Many gold deposits contain cemented muds, which have a particle size of more than 100 mm. If the mud mass is not broken, it will be removed along with the waste rock during the screening process, resulting in loss of gold. In addition, the cement can be cemented on gravel or pebbles, and if it is not broken, it will also cause gold loss during the screening process.

On the gold mining ship, the crushing and screening operations are completed together inside the cylindrical sieve. The cylindrical sieve is provided with intermittent spiral angle steel. During operation, the washing water pressure in the cylindrical sieve should be no less than 35 kPa. In the land fixed plant, a washing bed is set up for disintegration and sieving. Two sets of Pinggui 50 or Pinggui i-100 water guns are used, and the flushing is repeated in the diagonal direction. The outlet pressure of the water gun is not less than 20 kPa.

Screening can eliminate 20-40% of waste rock (gravel, pebbles), which is an indispensable operation for gold ore dressing. The determination of reasonable screening parameters must be based on the measurement data of the strength of the gold in the original ore. At present, the screen holes selected by China's gold mines are generally 10-20 mm. If the fixed chute is used for roughing equipment, the screen holes can be larger, but not more than 60 mm. The screening equipment of the fixed selection plant is mostly grid sieve and vibrating screen, while the gold mining vessel uses a cylinder sieve. The flushing on the sieve not only improves the screening efficiency, but also further disintegrates the cement. Therefore, the screening operation of the gold mine is mostly a water sieve. The flushing capacity of the water screen is determined according to the requirements of the washing, and should meet the concentration requirements of the lower sorting operation as much as possible. If the tank is rough-selected, the flushing amount should be 8-14 times that of the sand ore.

Second, de-sludge

Materials less than 0.1 mm in gold ore are generally free of gold or contain little gold. For example, the gold of less than 0.1 mm in the gold deposit of Hunchun Gold Mine accounts for 0.18%, while the same grade of mineral mud accounts for 13.77% of the original ore. Gold less than 0.1 mm, commonly known as floating gold, is difficult to recycle during the sorting process, while the same grade of slime interferes with the sorting process, especially the mechanical sorting process. Therefore, in the sand gold mining machinery concentrator, always try to remove the slime less than 0.1 mm. The degreasing equipment commonly used in production is a mud hopper of various specifications, and the material allowed by the chute selection is wide in size and large in processing amount, so that the chute is not delimed before being selected.

c, sorting

Practice has proved that the re-election method is the most effective and economical method for processing gold deposits. Due to the different particle size composition of gold in the gold deposits, the effective grain size limits of the various re-election equipment are different. Therefore, the reasonable sand gold ore sorting process should be the joint operation of several re-election equipment.

The gold-bearing concentrate obtained from the rough selection section has a gold grade of 100 g/ton and a heavy sand mineral of more than 1-2 kg/ton. There are currently three methods for the treatment of gold-bearing coarse concentrate: 1. Manual gold panning After the gold particles are washed out, the heavy sand is discarded; 2. The mercury is mixed with the mercury in the mixing tank, and the heavy sand is discarded after obtaining the mercury paste; 3. After the gold is extracted by manual washing or amalgamation, the heavy sand is sent to the concentrate processing plant for treatment. The magnetic separation and electric selection methods respectively recover various heavy sand minerals.