A pre-acidification displacement dehydration system before immersion

Abstract

The present invention provides a pre-leaching pre-acidification displacement dehydration system, the system comprises a high-efficiency thickener, a discharge channel is provided at the bottom of the high-efficiency thickener, a filter is provided directly below the discharge channel, and a pulping tank is provided directly below the end of the filter; the filter comprises two operating areas, a neutral liquid dehydration area and an acid solution washing area; the acid in the acid solution washing area and the pulping tank comes from the overflow of the CCD thickener after the leaching operation, and the filtrate generated in the acid solution washing area is returned to the CCD thickener; a feeding device and an overflow tank are respectively provided on the top of the pool wall of the high-efficiency thickener, the overflow in the overflow tank is recycled as process water, the filtrate generated in the neutral liquid dehydration area is returned to the feeding device, and the filter cake generated in the acid solution washing area is transmitted to the pulping tank, and the filter cake enters the leaching operation after being pre-acidified in the pulping tank.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a pre-leaching pre-acidification displacement dehydration system. Background Art

[0002] The wet process of leaching-extraction-electrodeposition-impurity removal-cobalt precipitation is a conventional process for treating copper-cobalt oxide ores. Copper-cobalt leaching requires the use of sulfuric acid as a leaching agent, and then the sulfuric acid in the leaching residue needs to be neutralized by adding lime. Therefore, reducing acid consumption can not only reduce the cost of sulfuric acid, but also reduce the cost of lime required for neutralization of leaching residue. It is of great significance to study the process and technology to reduce acid consumption in the wet process.

[0003] Water is the carrier in wet mining production. There is a water balance relationship in each system of the wet process. A reasonable and effective pre-slurry dehydration process is one of the effective ways to control the water balance of the system.

[0004] In order to recycle the sulfuric acid in the raffinate and ensure the concentration of the leaching operation, the current wet copper and cobalt extraction process will process the pre-leaching materials. Usually, a two-stage dehydration process is used, which is a high-efficiency thickener plus a rubber horizontal belt vacuum filter. The filter cake is re-pulped with the raffinate and then fed into the leaching operation. This process can recycle the sulfuric acid in the raffinate and reduce the acid consumption of the process to a certain extent, but there are the following problems:

[0005] (1) The water content of the filter cake in the conventional two-stage dehydration process is about 20%, which is neutral water. When the filter cake is re-pulped, raffinate is added to dilute it to the leaching operation concentration. Since there is already 20% neutral water in the filter cake, only a limited amount of raffinate can be added, resulting in a low recycling rate of sulfuric acid in the raffinate, which cannot minimize acid consumption;

[0006] (2) The approximately 20% neutral water contained in the filter cake can easily affect the water balance of the system after entering the leaching system.

[0007] Therefore, it is of great significance to study a technology that can maximize the recycling of acidic solution to reduce process acid consumption and improve water return rate. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a pre-leaching pre-acidification displacement dehydration system, the system includes a high-efficiency thickener, a discharge channel is provided at the bottom of the high-efficiency thickener, a filter is provided directly below the discharge channel, and a slurry making tank is provided directly below the end of the filter; the filter includes two operating areas, a neutral liquid dehydration area and an acid solution washing area; the acid in the acid solution washing area and the slurry making tank comes from the overflow of the CCD thickener after the leaching operation, and the filtrate generated in the acid solution washing area is returned to the CCD thickener.

[0009] Wherein, the filter is a horizontal belt vacuum filter.

[0010] Wherein, a feeding device and an overflow trough are respectively provided on the top of the high-efficiency thickener pool wall.

[0011] Wherein, the overflow liquid in the overflow tank is recycled as process water.

[0012] Wherein, the filtrate produced in the neutral liquid dehydration zone is returned to the feeding device.

[0013] Wherein, the filter cake produced in the acid solution washing zone is transferred to the pulping tank.

[0014] The filter cake is pre-acidified in the pulping tank and then enters the leaching operation.

[0015] Beneficial effects of the present invention:

[0016] The pre-leaching pre-acidification displacement dehydration system provided by the present invention can replace the neutral water in the feed with an acidic solution before the leaching operation, and has the following advantages:

[0017] (1) It effectively reduces the amount of sulfuric acid added during the leaching process, which can minimize acid consumption and make the pH value of the leaching slurry and the copper-cobalt leaching process more stable. On the other hand, pre-acidification before leaching actually increases the leaching time and can effectively improve the copper-cobalt leaching rate.

[0018] (2) The neutral water from the horizontal belt vacuum filter and high-efficiency thickener can be recycled as process water, which not only improves the water return rate, but also reduces the water entering the leaching operation, avoiding excessive water affecting the water balance of the leaching system;

[0019] (3) After cobalt leaching, the overflow product generated by the CCC countercurrent washing of the material is partially diverted to the dehydration process. The pre-acidification displacement dehydration technology before leaching also effectively reduces the amount of solution in the subsequent cobalt precipitation process. Under the premise of the same cobalt production capacity, the investment in cobalt precipitation equipment such as cobalt precipitation tanks and thickeners can be reduced by more than 20%.

[0020] The pre-leaching pre-acidification displacement dehydration system provided by the present invention achieves three goals at one stroke, not only stabilizing the leaching process operation and improving the copper-cobalt leaching rate; it also reduces the acid consumption of the leaching process and improves the water return rate, thereby reducing the operating cost and the equipment investment of the cobalt precipitation process, and has the advantages of high efficiency, economy, and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 Schematic diagram of a pre-acidification displacement dehydration system provided by an embodiment of the present invention;

[0023] In the figure: 1-high efficiency thickener, 101-feeding device, 102-overflow trough, 2-ore discharge channel, 3-horizontal belt vacuum filter, 301-neutral liquid dehydration area, 302-acid solution washing area, 4-slurry making tank, 5-CCD thickener. DETAILED DESCRIPTION

[0024] The following are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications may be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

[0025] The present invention provides a pre-acidification displacement dehydration system before immersion, such as Figure 1 As shown, the system includes a high-efficiency thickener 1, a discharge channel 2 is provided at the bottom of the high-efficiency thickener 1, a filter 3 is provided directly below the discharge channel 2, the filter 3 is a horizontal belt vacuum filter 3, and a pulping tank 4 is provided directly below the end of the horizontal belt vacuum filter 3; the horizontal belt vacuum filter 3 includes two operating areas, the front half is a neutral liquid dehydration area 301, and the rear half is an acid solution washing area 302; the acid in the acid solution washing area 302 and the pulping tank 4 comes from the acid after the leaching operation The CCD thickener 5 overflows, and the filtrate produced in the acid solution washing zone 302 is returned to the CCD thickener 5; a feeding device 101 and an overflow trough 102 are respectively provided on the top of the pool wall of the high-efficiency thickener 1, and the overflow liquid in the overflow trough 102 is recycled as process water, and the filtrate produced in the neutral liquid dehydration zone 301 is returned to the feeding device 101; the filter cake produced in the acid solution washing zone 302 is transferred to the pulping tank 4, and the filter cake enters the leaching operation after being pre-acidified in the pulping tank 4.

[0026] The pre-acidification displacement dehydration system provided by the present invention includes a filter cake pre-acidification displacement dehydration process as follows:

[0027] After the copper-cobalt ore pulp is dehydrated by the high-efficiency thickener 1, the bottom flow liquid flows to the horizontal belt vacuum filter 3 through the ore discharge channel 2, and the overflow liquid is recycled as process water to improve the water return rate; the bottom flow liquid first passes through the neutral liquid dehydration zone 301 for dehydration, the pH value of the neutral liquid dehydration zone 301 is 7, and the water content of the filter cake after dehydration is 20%. While dehydrating in the acid solution washing zone 302, the filter cake is sprayed with acidic water with a pH value of 2 to replace all the neutral water in the filter cake with acidic water; the acid in the acid solution washing zone 302 comes from the overflow of the CCD thickener 5 after the leaching operation, and the generated acidic filtrate is returned to the CCD thickener 5. The filter cake after dehydration and pickling enters the pulping tank 4, and the pickling solution is sprayed into the pulping tank 4. The pickling solution comes from the overflow of the CCD thickener 5 after the leaching operation. The filter cake enters the leaching operation after being pre-acidified in the pulping tank 4.

[0028] The above embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A pre-acidification displacement dehydration system before immersion, characterized by: The system comprises a high-efficiency thickener (1), a discharge channel (2) is provided at the bottom of the high-efficiency thickener (1), a filter (3) is provided directly below the discharge channel (2), and a pulping tank (4) is provided directly below the end of the filter (3); the filter (3) comprises two operating areas, a neutral liquid dehydration area (301) and an acid solution washing area (302); the acid in the acid solution washing area (302) and the pulping tank (4) comes from the overflow of a CCD thickener (5) after a leaching operation, and the filtrate generated in the acid solution washing area (302) is returned to the CCD thickener (5).

2. A pre-immersion pre-acidification displacement dehydration system according to claim 1, characterized in that: The filter (3) is a horizontal belt vacuum filter.

3. A pre-immersion pre-acidification displacement dehydration system according to claim 2, characterized in that: A feeding device (101) and an overflow trough (102) are respectively provided on the top of the pool wall of the high-efficiency thickener (1).

4. A pre-immersion pre-acidification displacement dehydration system according to claim 3, characterized in that: The overflow liquid in the overflow tank (102) is recycled as process water.

5. A pre-immersion pre-acidification displacement dehydration system according to claim 3, characterized in that: The filtrate produced in the neutral liquid dehydration zone (301) is returned to the feeding device (101).

6. A pre-immersion pre-acidification displacement dehydration system according to any one of claims 1 to 5, characterized in that: The filter cake produced in the acid solution washing zone (302) is transferred to the pulping tank (4).

7. A pre-immersion pre-acidification displacement dehydration system according to claim 6, characterized in that: The filter cake is pre-acidified in the slurry making tank (4) and then enters the leaching operation.

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