Leaching Tank

What is Leaching Tank?

Agitation tanks are also called leaching agitation tanks or Stirring Tanks. According to the different structure of the agitation tank, it can be divided into two types: with center ore circulating cylinder (pic. 1) and without center ore circulating cylinder (pic. 2); according to the different uses, it can be divided into four types: slurry agitation tank, agitation storage tank, lifting agitation tank and chemical agent agitation tank; according to the different shape of the bottom, it can be divided into two types: flat-bottomed and conical-bottomed.

Double impeller Leaching Tank is suitable for gold leaching, adsorption and other mixing operations in which the specific gravity is small, the viscosity is low, the settling speed is slow, the particle size of the ore in -200 mesh accounts for more than 90%, and the concentration of the slurry is less than 45%.

What is the core function of a leaching tank?

The core function of a leaching tank goes far beyond stirring the slurry; it is about creating a dynamic environment that allows the chemical reaction to occur fully. Its primary task is to achieve complete suspension of the minerals—ensuring that every solid particle continuously participates in the reaction, rather than settling at the bottom. Once sedimentation occurs, valuable metals become trapped within the rock and cannot be extracted.

Simultaneously, the leaching tank must efficiently introduce oxygen into the liquid phase. In the gold cyanide process, oxygen is as crucial as cyanide; oxygen deficiency directly halts the leaching reaction. Therefore, a qualified leaching tank actually performs three key tasks simultaneously: solid suspension, gas dispersion, and chemical reagent mixing. These three elements work synergistically to ensure effective contact between cyanide and oxygen on the ore particle surface, transferring the target metal from the solid phase to the solution. In short, the leaching tank is the “reaction heart” of the entire hydrometallurgical plant—the slurry is pumped into it, undergoes a series of precisely controlled reactions, and then the valuable metal is released.

What Is Leaching Tank Used For?

The Leaching Tank can be divided into four kinds according to the use:
(1) Slurry Leaching Tank: used for slurry mixing before flotation operation, so that the ore particles are suspended and fully contacted and mixed with chemicals, in order to prepare for the flotation operation.

(2) Stirring storage tank: used for slurry stirring and storage. It is necessary to emphasize that, in the ferrous, non-ferrous metal concentrate slurry and coal slurry pipeline transportation, the need to use a large Leaching Tank.

(3) lifting Leaching Tank: both stirring and lifting, lifting height can reach about 1.5 meters. Mainly used in mineral processing plant in the slurry self-flow height difference is not enough or the difference is small should not be pumped.

(4) Pharmacy Leaching Tank: used in flotation plant for the preparation of various pharmaceutical operations. It should be noted that the nature of various chemicals is different, the choice of material for the Leaching Tank should be different, because some chemicals have strong corrosive, we sell Leaching Tank, in the chemicals Leaching Tank and impeller are specially lined with self-produced wear-resistant rubber, basically most of the chemicals can be corrosion-resistant.

How do CIL and CIP processes change the tank design?

The biggest difference between CIL (Carbon-in-Pulse) and CIP processes lies in the activated carbon treatment method, thus requiring different tank designs. CIL involves simultaneous gold leaching and adsorption in the same tank. CIP, on the other hand, involves leaching in a series of tanks first, then sending the resulting slurry to a separate adsorption tank to adsorb activated carbon. Gold mine CIL plants must be equipped with tanks capable of both leaching and adsorption.

In CIL tanks, the slurry is suspended primarily by powerful agitators, but abrasive stirring must be avoided to prevent breakage of the activated carbon particles. If the activated carbon is broken into too small pieces, the fine powder cannot be captured and will be lost along with the gold it carries. Therefore, specialized and suitable agitators are required. CIL tanks also require inter-tank screens—large-mesh panels that allow the slurry to pass through while trapping larger activated carbon particles. In gold mine CIP plants, the initial leaching tanks do not contain activated carbon, so these screens are unnecessary.

Technical Parameters of Leaching Tankk

Model	Tank Specifications (Diameter x Height) (mm)	Effective Volume (m³)	Impeller Speed ​​(r/min)	Impeller Diameter (mm)	Motor Model	Motor Power (kW)	Gearbox Model	Tank Weight (kg)	Total Weight (kg)
SJ2.0X2.5	2000X2500	7.07	52	909	Y100L1-4	2.2	XLD2.2-4-29	1609	2144
SJ2.5X2.5	2500X2500	10.8	43	935	Y112M-4	4	XLD4-5-35	2159	2729
SJ2.5X3.15	2500X3150	13.92	52	935	Y100L1-4	2.2	XLD2.2-4-29	2398	3095
SJ3.0X3.0	3000 X3000	19	43	1130	Y112M-4	4	XLD4-5-35	3480	4583
SJ3X3.15	3000X3150	20						3480	4160.6
SJ3X3.5	3000X3500	22.97						3211	4334.6
SJ3.15X3.55	3150X3550	25.73		1260				3433.5	4322.8
SJ3.5X3.5	3500X3500	31.3	52	1310	Y132S-4	5.5	XLD5.5-5-29	3480	5025
SJ3.5X4	3500X4000	35.6						4230	5429
SJ3.55X4.0	3550X4000	36.8	43		Y112M-4	4	XLD4-5-35	4260	5025
SJ3.7X4.2	3700X4200	42	42				XLD4-5-43	5266	6153
SJ4.0X4.5	4000 X4500	52.78	35	1750	Y132M-4	7.5	XLD7.5-7-43	6397	7569
SJ4.0X6	4000 X6000	71	33	1750	Y160M-4	11	GRF137-Y11- 4P-44.65-M4	7681	9200
SJ4.5X5.0	4500 X5000	74.75	35	1750	Y132M-4	7.5	XLD7.5-7-43	8614	10864
SJ5.0X5.6	5000X5600	104.5	31	2046	Y160M-4	11	XLD11-8-47	8740	14291
SJ5.5X6.0	5500 X6000	135.42		2100				12467	18745
SJ6.5X7.0	6500 X7000	215	21	2400	Y180L-4	22	GRF147-Y22- 4P-70.87	17890	25978
SJ7.0X7.5	7000 X7500	269		2400	Y200L2-6	22	XLD22-10-47	20505	29030
SJ7.5X8.0	7500 X8000	331	23	2900	Y200L2-6	22	BLD7-43-22L	22552	32796
SJ8.0X8.5	8000X8500	402	18.5	3200	Y250M-8	30	TPS315-3F	30559.5	42467.3
SJ8.5X9.0	8500X9000	480	18.5	3300	Y250M-8	30	TPS315-3F	34130	46623

Working Principle of Leaching Tank

The slurry in the Leaching Tank is dragged and stirred by the double impellers, flowing from top to bottom in the center, diffused by the peripheral damping plate, and air is fed into the lower end of the shaft, mixing with the slurry and circulating upward to form a homogeneous suspended mixture.

Advantageous features of Leaching Tank

• The movement of the ore flow is smooth, the slurry is evenly mixed, and the power consumption is low.
• Air enters into the trough through the transmission hollow shaft, stirred by the blades, the air is evenly dispersed.
• Compact structure, easy maintenance.
• The hollow shaft is ventilated to the bottom, and the air enters the tank through it, which is evenly dispersed and has small air bubbles.
• Adopting two new impellers, the impeller diameter of the Leaching Tank is large, the rotational speed is low, the mixing power consumption is small, and the wear and tear of carbon can be reduced.
• Moderate stirring intensity, consistent distribution of slurry concentration and fineness in the tank, which can improve the leaching rate of cyanide and the adsorption rate of charcoal.
• The impeller of leaching agitation tank is lined with wear-resistant rubber, with low rotational speed and long service life.

Leaching Tank FAQ

Q: What are the main uses of leaching tanks?

A: Leaching tanks are mainly used in hydrometallurgical processes to extract valuable metals, such as gold, silver, and copper, from ores using chemical solvents (such as sodium cyanide solution or sulfuric acid).

Q: What are the common types of leaching tanks?

A: The main types include mechanically stirred tanks, air-stirred tanks (such as Pachuca tanks), combined stirred tanks, and dedicated tanks for CIL (carbon-in-lime) and CIP (carbon-in-pulp) processes.

Q: What is the difference between CIL and CIP leaching tanks?

A: CIP involves leaching followed by activated carbon adsorption; CIL, on the other hand, performs leaching and adsorption simultaneously in the same tank, resulting in higher efficiency and an extraction rate of up to 96%.

Q: How to choose a suitable leaching tank?

A: The selection should be based on a comprehensive consideration of factors such as material characteristics, processing scale, energy consumption, the corrosiveness of the solution (whether a corrosion-resistant lining is required), and the stirring method.

Q: What materials are typically used for leaching tanks?

A: The tank body is usually made of steel plate or reinforced concrete, and the inner wall is lined with anti-corrosion materials such as rubber, fiberglass, acid-resistant ceramic tiles, or lead sheet to resist chemical corrosion.

Q: Which is better, an air-mixed tank or a mechanically mixed tank?

A: Air-mixed tanks have a simple structure, no transmission parts, and are easy to maintain, but consume more energy; mechanically mixed tanks have stronger agitation and lower energy consumption, but require higher wear resistance and corrosion resistance.

Q: What is the typical volume of a leaching tank?

A: Common industrial leaching tank volumes are 50-100 cubic meters, with large tanks reaching 120-400 cubic meters, showing a trend towards larger sizes.

Q: What are the key factors affecting leaching efficiency?

A: The main factors include material particle size, slurry concentration, temperature, pH value, dissolved oxygen content, agitation intensity, and leaching time.

Q: How to maintain a leaching tank to extend its service life?

A: Regularly check the integrity of the inner lining anti-corrosion layer, calibrate the pH and ORP sensors, clean scale from the agitator blades, and check for blockages in the air distribution pipes.

Q: What safety precautions should be taken when operating a leaching tank?

A: When handling hazardous reagents such as cyanide or strong acids, ensure the tank is well-sealed, equipped with ventilation and leak detection systems, and that operators wear protective equipment.