Method for co-processing heavy non-ferrous metallurgy solid waste

Abstract

The invention discloses a heavy non-ferrous metallurgy solid waste co-processing method, which fully considers compatibility and synergistic effect of types and properties of metals contained in various solid wastes, and reasonably combines a low-temperature arsenic and mercury removal technology and a mature technology for treating various solid wastes to form a set of systematic solid waste comprehensive treatment technology. Therefore, all-directional ordered control of solid waste from generation, collection, transportation, storage, treatment and disposal is achieved. According to the method, a technical solution is provided for centralized treatment of single-metal or multi-metal hazardous waste with a small amount, scale benefits are formed, the treatment cost is reduced, the metal recovery rate is improved, and meanwhile pollution factors are relatively centralized and convenient to treat. The problems that the cost is high and pollutants are dispersed due to the fact that a small amount of solid hazardous waste such as smoke dust, cobalt slag, copper slag, copper-cadmium slag, anode mud and acid mud is independently treated are fundamentally solved.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection treatment, and in particular to a method for coordinated disposal of heavy nonferrous metallurgical solid waste. Background Art

[0002] Various solid hazardous wastes generated during the heavy nonferrous smelting process include smelting smoke collected by dust collectors, neutralized slag produced by wastewater treatment systems, anode mud, acid mud, copper-cadmium slag and other purified slags. In addition to containing a large amount of heavy metals such as copper, lead and zinc, they also contain rare and precious metals such as germanium, indium and silver. They are a serious pollutant and a resource with high utilization value. After years of research, their classification and treatment technology has become mature. The best practical method selected by enterprises for different solid hazardous wastes depends on many factors such as the effectiveness, applicability, safety standards and cost of treatment or disposal. Due to the wide variety and complex market segments, it is easy to have irregular and incomplete treatment, which will cause secondary pollution to the environment. With the gradual increase in the production capacity of copper, lead and zinc, the amount of solid hazardous waste will gradually increase, and environmental protection requirements are becoming increasingly stringent. The original dispersion and classification treatment technology can no longer fully meet environmental protection requirements, and the treatment of hazardous waste is becoming increasingly difficult. Summary of the invention

[0003] In view of the above problems, the synergistic extraction technology proposed in the present invention adopts a combined process flow of pyrometallurgy and hydrometallurgy, fully utilizes the compatibility and synergistic effect of resources, and forms a systematic comprehensive hazardous waste treatment technology - multi-metal synchronous separation and extraction technology, which provides a technical solution for the centralized disposal of small amounts of single metal or multi-metal hazardous wastes. It fundamentally solves the problems of high cost and scattered pollutants in the separate treatment of small amounts of solid hazardous wastes such as smoke, cobalt slag, copper slag, copper-cadmium slag, anode mud, and acid mud, and also makes up for the shortcomings that low-content metals are difficult to recover or the recovery rate is low, and the generated waste slag needs to be treated separately.

[0004] Specifically, the present invention provides a method for the coordinated disposal of heavy nonferrous metallurgical solid waste, comprising the following steps:

[0005] S1. Analyze and classify solid waste;

[0006] S2. Different types of solid waste enter the corresponding primary treatment process for treatment, and then the products are sent to the lower-level treatment process for treatment.

[0007] Optionally, in step S1, the solid waste is divided into arsenic-mercury-containing solid waste and arsenic-free solid waste.

[0008] Optionally, in step S1, the solid waste not containing arsenic and mercury includes solid waste suitable for wet treatment and solid waste suitable for pyrolysis treatment.

[0009] Optionally, in step S2, the solid waste treatment process includes the following steps:

[0010] S21, low temperature and high efficiency arsenic and mercury removal process;

[0011] S22, rotary kiln volatilization process;

[0012] S23. Hydrometallurgical treatment or pyrometallurgical treatment.

[0013] Optionally, in step S2, the first treatment process of arsenic-containing solid waste and mercury-containing solid waste is step S21, and the products of the low-temperature and high-efficiency arsenic and mercury removal process, arsenic trioxide and metallic mercury, are stored or sold, and the product arsenic-removed mercury roasting material enters step S22.

[0014] Optionally, in step S21, the arsenic removal treatment adopts sulfuric acid aging pretreatment, followed by roasting.

[0015] Optionally, in step S21, the mercury removal treatment adopts mixed alkali method slurry pretreatment, aging and then distillation.

[0016] Optionally, the first treatment process suitable for pyrometallurgical treatment of solid waste is step S22, solid waste materials with similar volatile components are fully mixed in proportion, and various easily volatile valuable metals including zinc, lead, germanium, indium, antimony and bismuth are enriched in the crude zinc oxide fume by controlling the volatilization conditions, and non-volatile metals including copper, cobalt, nickel, etc. enter the slag; the crude zinc oxide fume enters the hydrometallurgical treatment process of step S23, and the slag enters the pyrometallurgical treatment process of step S23.

[0017] Optionally, in step S22, by studying the properties of various solid wastes including copper-cadmium slag, cobalt slag, acid mud, copper fume, arsenic-removed roasting material and mercury-removed material of step S21, according to the chemical properties, occurrence state and content of valuable elements, taking into full consideration the treatment process and distribution of harmful impurities, and combining with influencing factors including physical properties and moisture, various solid wastes are mixed evenly.

[0018] Optionally, in the step S23, the first treatment process suitable for wet treatment of solid waste is step S23, and the hydrometallurgical treatment process is: the crude zinc oxide smoke suitable for wet treatment of solid waste and the product of step S22 is leached with dilute sulfuric acid, and then according to the characteristics of various metals, chemical purification separation or extraction methods including replacement and precipitation are adopted to separate and purify them one by one, and finally a series of products with zinc sulfate heptahydrate as the main component and various concentrates or metal compounds such as lead, germanium, antimony, tin and bismuth as the auxiliary components are produced.

[0019] Optionally, in step S23, the pyrometallurgical treatment process includes the following steps:

[0020] S231, slag smelting;

[0021] S232, multi-element alloy electrometallurgy;

[0022] S233, multi-metal extraction and separation process.

[0023] Optionally, in step S231, alkaline flux limestone is added to the slag according to the CaO-MgO-SiO2 ternary phase diagram, and the weakly acidic slag is controlled to undergo reduction smelting to obtain a multi-element alloy and smelting slag.

[0024] Optionally, in step S232, the multi-element alloy is melt-cast into a soluble anode plate, a copper sulfate electrolyte is prepared, and the electrolysis conditions are controlled to obtain cathode copper, cobalt, and nickel dissolved into the electrolyte; iron, gold, and silver enter the anode mud to achieve effective separation of multiple metals; and part of the circulating electrolyte is opened to the multi-metal extraction process for extraction, purification, and separation of cobalt and nickel.

[0025] Optionally, in step S233, the cobalt-nickel electrolyte is extracted, purified and separated using a P204 extractant.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides a method for the coordinated disposal of heavy nonferrous metallurgical solid waste, which fully considers the compatibility and synergistic effect of the types and properties of metals contained in various solid wastes, and rationally combines low-temperature arsenic and mercury removal technology with mature technologies for the treatment of various solid wastes to form a set of systematic comprehensive solid waste treatment technologies, so as to achieve all-round and orderly control of solid waste from generation-collection-transportation-storage-treatment and disposal. The present invention provides a technical solution for the centralized disposal of small amounts of single metal or multi-metal hazardous wastes, forms economies of scale, reduces treatment costs, and improves metal recovery rates. At the same time, the pollution factors are relatively concentrated and easy to handle. It fundamentally solves the problem of high cost and dispersed pollutants in the separate treatment of small amounts of solid hazardous wastes such as smoke, cobalt slag, copper slag, copper-cadmium slag, anode mud, and acid mud.

[0028] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of the method for coordinated disposal of heavy nonferrous metallurgical solid waste according to the present invention. DETAILED DESCRIPTION

[0030] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Figure 1The present invention is a flow diagram of the method for the coordinated disposal of heavy non-ferrous metallurgical solid wastes. First, various solid wastes are classified and analyzed, and those that need to be de-arsenicized and de-mercured are de-arsenicized and de-mercured; those suitable for wet treatment are directly introduced into the wet treatment system for treatment, and those suitable for pyrometallurgical treatment are fully mixed in proportion with hazardous waste materials with similar volatile components. By controlling the volatilization conditions, various valuable metals that are easy to volatilize, such as zinc, lead, germanium, indium, antimony and bismuth, are enriched in the crude zinc oxide smoke, and metals that are not easy to volatilize, such as copper, cobalt, nickel, etc., enter the slag;

[0032] Secondly, the crude zinc oxide dust rich in various valuable metals is leached with dilute sulfuric acid, and then separated and purified one by one by chemical purification separation or extraction methods such as replacement and precipitation according to the characteristics of various metals, and finally a series of products are produced, mainly zinc sulfate heptahydrate, supplemented by various concentrates or metal compounds such as lead, germanium, antimony, tin and bismuth; the pyrometallurgical slag containing copper, cobalt, nickel and other non-volatile substances is pyrometallurgically smelted into alloys and recycled through methods such as electrochemical dissolution. The waste slag produced finally meets the requirements of general solid waste after pyrometallurgical treatment, and can be used as building materials or landfilled. The wastewater generated during the treatment process is treated and returned to leaching or pyrometallurgical slag quenching, truly achieving zero wastewater discharge.

[0033] Specifically, an embodiment of the present invention provides a method for the coordinated disposal of heavy nonferrous metallurgical solid waste, comprising the following steps:

[0034] S1. Analyze and classify solid waste;

[0035] S2. Different types of solid waste enter the corresponding primary treatment process for treatment, and then the products are sent to the lower-level treatment process for treatment.

[0036] The solid waste treated by the embodiment of the present invention and its composition are as follows:

[0037] (1) Copper-cadmium slag

[0038] Various valuable metals exist mostly in the form of metal elements, oxides, and salts.

[0039] Table 1 Analysis results of copper-cadmium slag of a certain enterprise

[0040]

[0041] (2) Cobalt slag

[0042] Among them, copper, cadmium and cobalt mostly exist as metal elements, lead exists in the form of sulfate, and iron exists in the form of hydroxide.

[0043] Table 2 Composition of cobalt slag of a certain enterprise

[0044]

[0045] (3) Iron alum slag

[0046] The high zinc content in iron alum slag mainly exists in the form of zinc ferrite, which is insoluble zinc. This part of zinc will crack under high temperature and high acid conditions. When zinc is dissolved, iron will also be dissolved into the solution, which will cause the cost to increase.

[0047] Table 3 Composition of iron alum slag of a certain enterprise

[0048]

[0049] (4) Copper fume

[0050] Copper dust is obtained by treating the flue gas produced by the roasting process of copper concentrate through a flue gas purification system. In addition to a high content of arsenic, it also contains a certain amount of valuable metals and rare metals, such as Pb, Zn, Cu, Sb, Sn and In. The dust phase is mainly composed of lead sulfate (PbSO4), zinc sulfate (ZnSO4·H2O), tin oxide (SnO2), lead arsenate (PbAs2O6, Pb2As2O7, arsenic trioxide (As2O3) and arsenic acid zinc-rich compound (FeZn)3(AsO4)2·8H2O) mineral phases. Due to the low content of Cu, Sb and In, the corresponding mineral phases were not detected in the XRD spectrum.

[0051] Table 4 Composition of copper smoke from a certain enterprise (wt%, *mg / kg)

[0052]

[0053] (5) Tin fume

[0054] Table 5 Composition of copper and tin smoke from a certain enterprise

[0055]

[0056] (6) Lead and antimony dust

[0057] The metals in the smoke are basically oxides, but due to the high arsenic content, it is difficult to avoid the dispersion of arsenic during the extraction process of traditional smelting technology, which makes it more difficult to extract other metals.

[0058] Table 6 Composition of lead and antimony dust from a certain enterprise

[0059]

[0060] (7) Lead anode mud

[0061] The physical phases are relatively complex and the crystallization is poor. The main physical phases of As, Sb, and Pb include: Pb3Sb2O7, Pb8OCl6(As2O5)2, PbHAsO4, Sb2O4, As2O3, PbSb2O6, etc. Most of them exist in complex physical phases, with only a small amount of simple oxides Sb2O4 and As2O3, and basically no metal elements. Arsenic mainly exists in the form of complex arsenides such as Pb8OCl6(As2O5)2 and PbHAsO4, which are difficult to volatilize, with only a small amount of As2O3.

[0062] Table 7 Material composition of lead anode mud of a certain enterprise (%)

[0063]

[0064] (8) Acid mud

[0065] Table 8 Acid sludge material composition of a certain enterprise

[0066]

[0067] In the step S1, the solid waste is divided into arsenic-mercury-containing solid waste (copper fume, tin fume, lead-antimony fume, acid mud, lead anode mud) and arsenic-free solid waste; arsenic-free solid waste includes solid waste suitable for wet treatment (copper-cadmium slag) and solid waste suitable for pyrometallurgical treatment (iron-vanadium slag, cobalt slag).

[0068] In step S2, the solid waste treatment process includes the following steps:

[0069] S21, low temperature and high efficiency arsenic and mercury removal process;

[0070] S22, rotary kiln volatilization process;

[0071] S23. Hydrometallurgical treatment or pyrometallurgical treatment.

[0072] In step S2, the first treatment process of arsenic-mercury-containing solid waste is step S21, and the products of the low-temperature and high-efficiency arsenic and mercury removal process, arsenic trioxide and metallic mercury, are stored or sold, and the product arsenic-removed mercury roasting material enters step S22.

[0073] In the step S21, the arsenic removal treatment adopts sulfuric acid aging pretreatment and is calcined at 450° C. for 2 hours. The As volatilization rate reaches 90.15%. The arsenic removal calcined material after arsenic removal contains 1-1.5wt% arsenic, and the arsenic removal efficiency is stable.

[0074] In step S21, the mercury removal treatment adopts mixed alkali method (5wt% sodium hydroxide + 10wt% sodium carbonate) slurry pretreatment, aging for 7 days, distillation at 650°C for 6-7h, the mercury distillation rate is greater than 99%, the direct recovery rate reaches more than 90%, and meets the requirements of industrial crude mercury products (purity above 99.9%).

[0075] For solid waste containing both arsenic and mercury, the process of removing arsenic first and then mercury is adopted.

[0076] The first treatment process suitable for pyrometallurgical treatment of solid waste is step S22, which is to study the batching method and proportion of solid waste materials with similar volatile components according to the chemical properties, occurrence state and content of valuable elements, and fully consider the treatment process and distribution of harmful impurities, and then combine the influencing factors such as physical properties and moisture to obtain a mixed material suitable for process treatment as shown in Table 9.

[0077] Table 9 Chemical composition of main elements of mixed materials

[0078]

[0079] By controlling the volatilization conditions, various volatile valuable metals including zinc, lead, germanium, indium, antimony and bismuth are enriched in the crude zinc oxide fume, and non-volatile metals including copper, cobalt, nickel, etc. enter the slag; the crude zinc oxide fume enters the hydrometallurgical treatment process of step S23, and the slag containing non-volatile metals including copper, cobalt, nickel, etc. is quenched with water to obtain high-boiling-point water-quenched slag, which enters the pyrometallurgical treatment process of step S23.

[0080] In the step S22, by studying the properties of various solid wastes including copper-cadmium slag, cobalt slag, acid mud, copper smoke, arsenic-removed roasting material and mercury-removed material of the step S21 product, according to the chemical properties, occurrence state and content of valuable elements, the harmful impurity treatment process and distribution are fully considered, and combined with influencing factors including physical properties and moisture, various solid wastes are mixed evenly. The mixed solid waste contains more than 10wt% zinc and more than 1wt% copper. It volatilizes at a high temperature of 1250°C, the volatilization rates of zinc and lead are ≥95%, the volatilization rates of germanium and indium are ≥90%, and the recovery rates of copper and cobalt are ≥95%.

[0081] In the step S23, the first treatment process suitable for wet treatment of solid waste is step S23, and the wet metallurgical treatment process is: the solid waste suitable for wet treatment and the product of step S22, crude zinc oxide smoke, are leached with dilute sulfuric acid, and then according to the characteristics of various metals, chemical purification separation or extraction methods including replacement and precipitation are adopted to separate and purify them one by one, and finally a series of products mainly composed of zinc sulfate heptahydrate and various concentrates or metal compounds such as lead, germanium, antimony, tin and bismuth are output for sale.

[0082] In step S23, the pyrometallurgical treatment process includes the following steps:

[0083] S231, slag smelting;

[0084] S232, multi-element alloy electrometallurgy;

[0085] S233, multi-metal extraction and separation process.

[0086] In the step S231, the slag of non-volatile metals including copper, cobalt, nickel, etc. is added with 5-20wt% alkaline flux limestone according to the CaO-MgO-SiO2 ternary phase diagram, and the weakly acidic slag is controlled to reduce the reduction smelting temperature and the slag viscosity. The reduction smelting is carried out at 1550°C for 8h to obtain a multi-element alloy containing 21wt% iron, 11.36wt% copper, 5.74wt% cobalt, 4.32wt% nickel, 216g / t silver, and 6.1g / t gold; the smelting slag is a general solid waste and is used as a raw material for cement production after water quenching.

[0087] In step S232, the multi-element alloy is melted into a soluble anode plate, and a copper sulfate electrolyte containing 40 g / L copper and 120 g / L sulfuric acid is prepared. The electrolyte is heated at a cell voltage of 1.2-2.4 V, a DC current of 110 A, and a current density of 160-200 A / m 2 Under the conditions of , the cathode copper obtained meets the national standard 1# copper and is sold; cobalt and nickel dissolve into the electrolyte; iron, gold and silver enter the anode mud for gold and silver extraction; and multiple metals are effectively separated. When cobalt and nickel in the circulating electrolyte are enriched to 10-25g / L, impurities such as iron, aluminum, magnesium, manganese, silicon and zinc in the solution are also enriched to 0.2-5g / L. Part of the circulating electrolyte is opened to the multi-metal extraction process for extraction, purification and separation of cobalt and nickel.

[0088] In step S233, the cobalt-nickel electrolyte is extracted, purified and separated using a P204 extractant, and the extraction conditions are as follows:

[0089] Extraction level: 10 levels of extraction, 5 levels of cobalt washing, 4 levels of copper washing, 3 levels of iron washing, 2 levels of stilling;

[0090] Extraction conditions: feed liquid flow rate is 150L / h, organic phase flow rate is 180L / h, organic phase saponification rate is 55%, cobalt washing flow rate is 30L / h, copper washing flow rate is 7.5L / h. The cobalt washing acid is 1.5mol / L hydrochloric acid, the copper washing acid is 2.8mol / L hydrochloric acid, and the iron washing acid is 8mol / L hydrochloric acid. When the iron washing acid is lower than 4.5mol / L, it is replaced. The products are cobalt oxide or cobalt sulfate, nickel oxide or nickel sulfate for sale.

[0091] After processing, the technical indicators of the main products of the present invention are shown in Table 10.

[0092] Table 10 Technical indicators of main products

[0093]

[0094] So far, the technical solution of the present invention has been described in combination with the above multiple embodiments, but it is easy for those skilled in the art to understand that the protection scope of the present invention is not limited to these specific embodiments. Without departing from the technical principles of the present invention, those skilled in the art can split and combine the technical solutions in the above embodiments, and can also make equivalent changes or replacements to the relevant technical features. Any changes, equivalent replacements, improvements, etc. made within the technical concept and / or technical principles of the present invention will fall within the protection scope of the present invention.

Claims

1. A method for the coordinated disposal of heavy nonferrous metallurgical solid waste, characterized in that: The steps include: S1. Analyze and classify solid waste; S2. Different types of solid waste enter the corresponding primary treatment process for treatment, and then the products are sent to the lower-level treatment process for treatment.

2. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 1, characterized in that: In the step S1, the solid waste is divided into arsenic-mercury-containing solid waste and arsenic-mercury-free solid waste; the arsenic-mercury-free solid waste includes solid waste suitable for wet treatment and solid waste suitable for pyrolysis.

3. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 2, characterized in that: In step S2, the solid waste treatment process includes the following steps: S21, low temperature and high efficiency arsenic and mercury removal process; S22, rotary kiln volatilization process; S23. Hydrometallurgical treatment or pyrometallurgical treatment.

4. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 3, characterized in that: In step S2, the first treatment process of arsenic-mercury-containing solid waste is step S21, and the products of the low-temperature and high-efficiency arsenic and mercury removal process, arsenic trioxide and metallic mercury, are stored or sold, and the product arsenic-removed mercury roasting material enters step S22.

5. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 3, characterized in that: In the step S21, the arsenic removal treatment adopts sulfuric acid aging pretreatment, followed by roasting; the mercury removal treatment adopts mixed alkali method slurry pretreatment, followed by aging and distillation.

6. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 3, characterized in that: The first treatment process suitable for pyrometallurgical treatment of solid waste is step S22, in which solid waste materials with similar volatile components are fully mixed in proportion, and various easily volatile valuable metals including zinc, lead, germanium, indium, antimony and bismuth are enriched in the crude zinc oxide fume by controlling the volatilization conditions, and non-volatile metals including copper, cobalt and nickel enter the slag; the crude zinc oxide fume enters the hydrometallurgical treatment process of step S23, and the slag enters the pyrometallurgical treatment process of step S23.

7. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 3, characterized in that: In the step S22, by studying the properties of various solid wastes including copper-cadmium slag, cobalt slag, acid mud, copper fume, arsenic-removed roasting material and mercury-removed material of the step S21 product, according to the chemical properties, occurrence state and content of valuable elements, the treatment process and distribution of harmful impurities are fully considered, and combined with the influencing factors including physical properties and moisture, various solid wastes are mixed evenly in proportion.

8. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 3, characterized in that: In the step S23, the first treatment process suitable for wet treatment of solid waste is step S23, and the hydrometallurgical treatment process is: the solid waste suitable for wet treatment and the product of step S22, crude zinc oxide smoke, are leached with dilute sulfuric acid, and then according to the characteristics of various metals, chemical purification separation or extraction methods including replacement and precipitation are adopted to separate and purify them one by one, and finally a series of products with zinc sulfate heptahydrate as the main component and various concentrates or metal compounds of lead, germanium, antimony, tin and bismuth as the auxiliary components are produced.

9. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 3, characterized in that: In step S23, the pyrometallurgical treatment process includes the following steps: S231, slag smelting; S232, multi-element alloy electrometallurgy; S233, multi-metal extraction and separation process.

10. The method for coordinated disposal of heavy nonferrous metallurgical solid waste according to claim 9, characterized in that: In the step S231, the slag is mixed with alkaline flux limestone according to the CaO-MgO-SiO2 ternary phase diagram, and the weakly acidic slag is controlled to perform reduction smelting to obtain a multi-element alloy and smelting slag; In step S232, the multi-element alloy is melted and cast into a soluble anode plate, a copper sulfate electrolyte is prepared, and the electrolysis conditions are controlled to obtain cathode copper, cobalt, and nickel dissolved into the electrolyte; iron, gold, and silver enter the anode mud, thereby achieving effective separation of multiple metals; a portion of the circulating electrolyte is opened to the multi-metal extraction process for extraction, purification, and separation of cobalt and nickel; In step S233, the cobalt-nickel electrolyte is extracted, purified and separated using an extractant.

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