The company is located in northern Utah, USA, with a production scale of 3,500 t/d.
Ore properties: gold occurs in carbonate rocks of hydrothermal account, and pyrite, marcasite, orpiment, realgar, barite and organic symbiosis. Gold exists not only in the vulcanization zone but also in the oxidation zone. In sulfide ore, gold is encapsulated in pyrite, pyrite and organic matter, and free gold is symbiotic with quartz and calcite . In oxidized ore, gold is present in a natural gold state. The natural gold inlay has a particle size of 10 to 1 μm, and more than half of the particle size is 5 μm or less.
The process is shown in the figure.
[next]
Broken into an open circuit. A double-knuckle jaw crusher of 1.07 m × 1.22 m was used . The crushed products are piled up with a radiant piler for use in the grinding circuit.
The grinding process is two-stage and one-closed. The first section is made of Ф6.1m×1.8m semi- auto-grinding machine . The discharge is graded by a 2.4m×4.9m Tyler sieve. The material on the sieve is less than 25mm. Self-grinding machine, materials larger than 25mm can be returned to the semi-autogenous mill, or can be piled up for building materials or heap leaching. The material under the sieve is directly fed into the cyclone. The cyclone grading equipment is 4 sets of 660mm Kleb. Krebs cyclone, cyclone grit feed into the Ф 3.8m × 4.7m ball mill . The overflow fineness is 80%~200 mesh, and a 30-mesh vibrating screen removes wood chips and other debris. The slurry after dedusting is dehydrated by a 46m EIMCO thickener, and the bottom of the thickener is fed into two buffer tanks. The purpose of the buffer tank is to stabilize the feed rate of the CIL system, and the pH is adjusted to add cyanide. Used as a leaching tank.
Charcoal leaching: The CIL system has 8 troughs, the slurry retention time is 24h, and the tank is equipped with a 24-mesh bridge screen, which is combined with a centrifugal charcoal pump for countercurrent charcoal. The carbon leaching tailings slurry is pumped into the tailings pond through the carbon safety screen. The tailings water is returned to the grinding circuit and is also used to dilute the slurry of the CIL system. The gold-bearing charcoal grade is 2400g/t, and after washing the pulp with a 610mm×1800mm carbon slurry separation sieve (28 mesh), it enters the gold recovery system.
The charcoal plant pickling operation is located before the desorption operation to prevent heavy metals and carbonates from entering the desorption electrowinning system. The pickling tank can hold 4.8t of charcoal. The pickling procedure is as follows: 1 pickling: soaking with 3% HNO3; 2 washing with water: flushing with tap water to neutral; 3 washing with alkali: soaking with 1% NaOH solution; 4 treatment with waste liquid: First neutralize with NaOH solution, then add Nat S to eliminate heavy metals in the waste liquid, such as Hg, Th, etc., so that it becomes a sulfide precipitate, and then discharged into the tailings pond.
Desorbing the electricity first sends the pickled charcoal to a preheating tank with an ejector. The preheating time is one night, and the preheating temperature is 82 ° C, so that the desorption time is greatly reduced. The desorption column size is Ф1.5m×6.4m, the designed carbon loading is 6t, the production is controlled at 4.8t, and the desorption electrowinning process is as follows:
1 Prepared in a desorbent preparation tank. 4 times the volume of the carbon bed desorbent;
2 pump the desorbed solution to the desorption column at a rate of 270 L/min. The noble liquid discharged from the desorption column is returned to the preparation tank before the gold-containing grade does not reach the electromagnetism requirement (the electroform reserve requires a gold content of 400×10 - 6 ~ 500 × 10 -6 );
3 Enter the precious liquid tank when the grade of the precious liquid reaches the electromagnetism requirement;
4 pump the precious liquid into the electric storage tank at a speed of 36L/min;
5 After the poor liquid contains less than 6×10 -6 , the electrowinning is stopped, and the poor liquid is sent to the CIL system or used to prepare the desorption liquid;
6 When the grade of gold charcoal is reduced to 30~60g/t, desorption is stopped. The desorbed charcoal was rinsed with 2 times the volume of carbon bed water.
Smelting: In addition to gold and silver , the gold-loaded cathodes taken out of the electrode pool contain mercury and other metals. Therefore, mercury must be removed by a steamer. The temperature of the evaporated mercury was 650 °C. The cathode after the mercury was evaporated was melted together with a flux in a 175 kW induction furnace to obtain a crude gold having a gold content of 60%, and then refining once to obtain a gold ingot having a purity of 80% or more. [next]
The activated carbon was regenerated using a Ф914mm×8300mm horizontal rotary kiln. The regeneration atmosphere was water vapor and the regeneration temperature was 810 °C. The plant believes that at 810 °C wood chips can be ashed and activated carbon can not, below this temperature can not make wood chips gray, higher than this temperature may make the activated carbon also gray. The regenerated carbon is cooled by water quenching and then classified by a 24-mesh dewatering sieve. The coarse carbon on the sieve is returned to the CIL system for use, and the fine carbon is filtered and recovered.
Technical data: The total gold recovery rate of Mercur Gold Project is 82%~87%, the process conditions are shown in Table 1, and the material consumption is shown in Table 2.
Table 1  Mercur  Gold  Project carbon slurry plant process conditions [302] | |||||
Grinding dense loop | Feeding granularity | CIL loop | Desorption time | 9.5h | |
Grinding fineness | 80%-200mm | Electric cell voltage | 2.5V | ||
Thickener feeding concentration | 16%~17% | Current | 50A/ pole | ||
Flocculant | Formulation concentration 0.3% | Cathode steel | 450g / pole | ||
Add concentration 0.03% | |||||
Thickener underflow concentration | 55% | Slurry concentration | 40%~45% | ||
Pickling | Total pickling time | 6h | Cyanide concentration | 0.05%~0.12% | |
Desorption electric product | Desorption temperature | Leaching time | 24h | ||
Desorption pressure | 0.03~0.35MPa | Adsorption time | 24h | ||
Desorption component | 1.0% NaOH | pH | 10.5 | ||
0.5% NaCN | Carbon density | 10g/L | |||
Table 2  Mercur  Gold  Project carbon pulp plant material consumption [302] | |||
material | consumption | material | consumption |
Sodium cyanide | 0.9~1.14kg/t | Flocculant | 30 g/t |
Activated carbon | 45~65g/t | Steel ball | 0.32 kg/t |
lime | 1.6kg/t | Nitric acid | 0.1 kg/t |
Sodium hydroxide | 2.7 kg/t | Sodium sulfide | 77 g/t |
Nanpi Jiantong Hardware Manufacturing Co.,Ltd. offers a wide range of metal brackets, include Angel brackets, corner brackets, L brackets, Steel Brackets, U shape brackets, solar brackets.
Material grade: stainless steel 301, stainless steel 304
Al5052,6061
steel DC01,DC04,ST12,Q235,SJ235R
galvanized steel sheet DX51D
Stock thickness ranges from 0.30mm-6.0mm for stainless steel
0.30mm-6.0mm for aluminum
0.20mm-6.0mm for carbon steel
Surface finishing: polishing, satin blasted, powder coating, electro plating, anodize
Application: connectors, mounting brackets, supports, chassis parts ..etc.
Metal Bracket,Aluminum Bracket,Stainless Steel Bracket,Steel Brackets
Nanpi Jian Tong Hardware Manufacturing Co., Ltd. , https://www.jiantongstamping.com