A heavy metal waste acid treatment process system

Abstract

This utility model relates to a heavy metal waste acid treatment process system, including a #1 neutralization tank. The outlet of the #1 neutralization tank is connected to the inlet of an acid leaching tank via a pipeline. A #1 filter press is installed at the outlet of the acid leaching tank. The filtrate outlet of the #1 filter press is connected to the inlet of a #2 neutralization tank via a pipeline. A #2 filter press is installed at the outlet of the #2 neutralization tank. The filtrate outlet of the #2 filter press is connected to a fluoride-chlorine removal system via a pipeline. The fluoride-chlorine removal system is sequentially connected to a cyclone arsenic removal system and a cyclone zinc removal system via pipelines. This utility model achieves efficient recovery of valuable metals from waste acid and white flue dust through technologies such as acid leaching neutralization, electrolytic fluoride-chlorine removal, and cyclone electrowinning arsenic and zinc removal. The treated solution meets the reuse requirements of the smelting acid purification process, truly achieving zero emissions, significantly improving resource utilization and reducing production costs.

Description

Technical Field

[0001] This utility model relates to the field of hydrometallurgical flue gas waste acid treatment technology, specifically to a heavy metal waste acid treatment process system. Background Technology

[0002] In the sulfuric acid production workshop of a non-ferrous metal smelter, during the purification process of washing and cleaning the smelting flue gas, impurities such as arsenic (As), fluorine (F), chlorine (Cl), and particulate matter in the flue gas dissolve into the circulating acid. As these impurities accumulate in the circulating acid, when their concentration reaches a certain threshold, a certain amount of waste acid needs to be discharged from the system to maintain normal operation. This waste acid typically has high acidity and contains various heavy metal ions and high concentrations of difficult-to-treat impurities such as arsenic, fluorine, and chlorine.

[0003] Currently, the main methods for treating this type of waste acid include the lime-gypsum process, chemical precipitation, and sulfidation. While these traditional methods can remove heavy metals and impurities from waste acid to some extent, they have significant shortcomings in achieving acid reuse and the recovery of valuable heavy metals. For example, the lime-gypsum process generates a large amount of gypsum slag, which not only increases the burden of solid waste treatment but may also lead to secondary pollution. Furthermore, existing processes often struggle to effectively remove arsenic and fluorine from waste acid, rendering the treated acid unsuitable for reuse and resulting in a waste of acid resources. Simultaneously, traditional methods have low efficiency in recovering valuable metals from waste acid, leading to poor economic returns.

[0004] Therefore, developing an efficient process system for treating waste acid containing heavy metals from non-ferrous metal smelting to achieve resource utilization of waste acid, reduce environmental pollution, and improve economic benefits has become an urgent technical challenge in this field. Utility Model Content

[0005] This invention provides a process system for treating heavy metal pollutants.

[0006] The specific technical solution is as follows: A heavy metal waste acid treatment process system includes a #1 neutralization tank, the outlet of which is connected to the inlet of an acid leaching tank via a pipeline. A #1 filter press is installed at the outlet of the acid leaching tank. The filtrate outlet of the #1 filter press is connected to the inlet of a #2 neutralization tank via a pipeline. A #2 filter press is installed at the outlet of the #2 neutralization tank. The filtrate outlet of the #2 filter press is connected to a fluoride-chlorine removal system via a pipeline. The fluoride-chlorine removal system is sequentially connected to a cyclone arsenic removal system and a cyclone zinc removal system via pipelines.

[0007] Furthermore, preferably, the waste heat steam from the No. 1 filter press is returned to the acid leaching tank for reuse via pipeline.

[0008] The beneficial effects of this invention are as follows: This invention achieves efficient recovery of valuable metals from waste acid and white flue dust through technologies such as acid leaching neutralization, electrolytic removal of fluorine and chlorine, and cyclone electrowinning for arsenic and zinc removal. The treated solution fully meets the reuse standards of the smelting acid purification process, truly achieving zero emissions, significantly improving resource utilization, and substantially reducing production costs. In the neutralization stage, this invention innovatively uses white flue dust as an acidity regulator. While adjusting the pH value, it effectively increases the concentration of valuable metals in the waste acid solution, creating extremely favorable conditions for subsequent separation and recovery of valuable metals. Furthermore, it successfully realizes the resource utilization of white flue dust, a solid waste, solving the problems of solid waste storage and subsequent treatment, reducing environmental pressure, and demonstrating significant economic and environmental benefits. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of a heavy metal waste acid treatment process system according to the present invention; In the diagram: 1-1# neutralization tank, 2-acid leaching tank, 3-1# filter press, 4-2# neutralization tank, 5-2# filter press, 6-fluorine and chlorine removal system, 7-cyclone arsenic removal system, 8-cyclone zinc removal system. Detailed Implementation

[0010] To make the technical problems and solutions solved by this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0011] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0012] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0013] like Figure 1As shown, a heavy metal waste acid treatment process system includes a neutralization tank 1#, the outlet of which is connected to the inlet of an acid leaching tank 2 via a pipeline. A filter press 3# is installed at the outlet of the acid leaching tank 2#, and the filtrate outlet of the filter press 3# is connected to the inlet of a neutralization tank 4# via a pipeline. A filter press 5# is installed at the outlet of the neutralization tank 4#, and the filtrate outlet of the filter press 5# is connected to a defluorination and chlorination system 6 via a pipeline. The defluorination and chlorination system 6# is connected in sequence to a cyclone arsenic removal system 7 and a cyclone zinc removal system 8 via pipelines.

[0014] The waste heat steam from filter press 3 is returned to acid leaching tank 2 via pipeline for reuse.

[0015] It should be noted that the above-mentioned equipment is all existing equipment. This application only involves the application of these existing equipment and does not involve the improvement of their structure. Moreover, the connection relationship of these equipment is not a direct structural connection, but a process connection relationship between process systems.

[0016] Working principle: (1) Acidity adjustment and acid leaching reaction The waste acid is transferred to neutralization tank 1 (No. 1) and a certain proportion of 98% sulfuric acid (H2SO4) is added to adjust its acidity, providing a stable and suitable acidic environment for the subsequent reaction with white flue dust. Subsequently, the adjusted waste acid is transferred to acid leaching tank 2, and white flue dust (a solid waste generated during metallurgical processes, containing various metal compounds) is added. In the acid leaching tank, the sulfuric acid reacts with the metal oxides in the white flue dust, as follows: Zinc oxide: ZnO + H2SO4→ ZnSO4+ H2O Copper oxide: CuO + H2SO4 → CuSO4 + H2O Through these reactions, the metal components enter the solution in the form of sulfates, thereby increasing the metal content (such as zinc) in the waste acid solution and creating conditions for subsequent metal recovery. After solid-liquid separation in filter press 3, filter residue (insoluble impurities in white soot) and filtrate are obtained. At the same time, the waste heat steam generated during the filtration process of filter press 3 can be connected to acid leaching tank 2 to provide the necessary temperature conditions for the acid leaching reaction.

[0017] (2) Secondary neutralization and metal leaching The filtrate is transferred to neutralization tank 4 (No. 2), where more white ash is added for neutralization. Sulfuric acid continues to leach metal oxides from the white ash, further increasing the metal content in the acidic solution. Simultaneously, if there is still excess acid in the solution, it will react with alkaline components (such as calcium carbonate, CaCO3) in the white ash. CaCO3+ H2SO4→ CaSO4+ H2O + CO2↑ This reaction neutralizes the acidity of the solution. After solid-liquid separation in filter press 5 (No. 2), neutralized residue and filtrate are obtained. The neutralized residue is sent to the lead-bismuth recovery system for further processing.

[0018] (3) Removal of fluoride and chlorine from the net capacitor The filtrate enters the fluoride and chlorine removal system 6, where the ion exchange technology of the Jingyuan capacitive deionization equipment is used to efficiently remove impurities such as fluoride and chlorine, thereby reducing the concentration of these harmful ions in the solution and creating conditions for subsequent treatment.

[0019] (4) Cyclone arsenic removal The solution after fluoride and chlorine removal enters the cyclone arsenic removal system 7. In the acidic solution, hydrogen sulfide (H2S) reacts with arsenic ions to form arsenic sulfide precipitate. The precipitate is obtained from trivalent arsenic ions (As...). 3+ For example, the reaction is as follows: 2H3AsO3+ 3H2S → As2S3↓ + 6H2O For pentavalent arsenic ions (As 5+ The reaction is as follows: 2H3AsO4 + 5H2S → As2S5↓ + 8H2O Subsequently, the centrifugal force field generated by the hydrocyclone is used to separate the solution and the precipitate during high-speed rotation, thereby obtaining arsenic slag and purified solution.

[0020] (5) Cyclone dezincification and zinc recovery The purified solution is transferred to the cyclone zinc removal system 8, where zinc is separated by extraction. Taking the commonly used acidic extractant HR as an example, zinc ions undergo an extraction reaction between the organic and aqueous phases: Zn 2+ + 2HR → ZnR2+ 2H⁺ In the subsequent back-extraction process, zinc is extracted from the organic phase and reintroduced into the aqueous phase using a suitable back-extraction agent (such as sulfuric acid solution). ZnR2 + H2SO4 → ZnSO4 + 2HR Finally, zinc is enriched by cyclone electrowinning to achieve efficient zinc recovery. The treated solution can be directly reused (returned to the smelting acid purification process) to achieve zero emissions.

[0021] Through the above process, the purification of waste acid, the enrichment and recovery of metals are achieved, while the harmful impurities are effectively treated, improving resource utilization and reducing environmental pollution.

[0022] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications or equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heavy metal waste acid treatment process system, characterized in that: The system includes a neutralization tank (1) with its outlet connected to the inlet of an acid leaching tank (2) via a pipeline. A filter press (3) is installed at the outlet of the acid leaching tank (2). The filtrate outlet of the filter press (3) is connected to the inlet of a neutralization tank (4) via a pipeline. A filter press (5) is installed at the outlet of the neutralization tank (4). The filtrate outlet of the filter press (5) is connected to a defluorination and chlorination system (6) via a pipeline. The defluorination and chlorination system (6) is connected to a cyclone arsenic removal system (7) and a cyclone zinc removal system (8) via pipelines.

2. The heavy metal waste acid treatment process system according to claim 1, characterized in that: The waste heat steam from the No. 1 filter press (3) is returned to the acid leaching tank (2) for reuse through pipelines.

Images