A method for solidifying arsenic in high-arsenic sludge using clay and copper slag

Abstract

The present invention relates to the field of sludge treatment technology, and more specifically, to a method for solidifying arsenic in high-arsenic sludge using clay and copper slag. The method involves drying the high-arsenic sludge at 105°C for 12 hours and grinding it to a particle size of less than 0.5 mm to obtain a dry material. The dry material is then mixed evenly with clay powder, copper slag, and coal powder. Water is then added, stirred at room temperature for a pre-reaction of 6 hours, and poured into a crucible to obtain a paste-like mixture A. The dry mixture A is then calcined at 850-900°C for 20-40 minutes under a protective atmosphere. The reaction product, after natural cooling, is then used as a roadbed material, for example. This method utilizes clay and copper slag calcination to treat high-arsenic sludge, resulting in low arsenic and other heavy metal leaching toxicity and excellent stability, while also fully utilizing metallurgical solid waste.

Description

Technical Field

[0001] The invention relates to the technical field of sludge treatment, and in particular to a method for solidifying arsenic in high-arsenic sludge by utilizing clay and copper slag. Background Art

[0002] With the continuous development of the economy and the increasing demand for non-ferrous metals, the large amount of high-arsenic sludge produced is in an unstable state. If left untreated and stored arbitrarily, the heavy metals leached from it will seriously pollute the ecological environment. Copper slag is a waste residue generated during the copper smelting process. While some of the slag is sold to cement plants, the remaining stockpile is also very large. Therefore, the harmless treatment and stabilization of high-arsenic sludge and the resource utilization of copper slag are of great significance to the sustainable development of the non-ferrous metal smelting industry.

[0003] Currently, calcium- and iron-containing substances are widely used to treat acidic arsenic-containing wastewater. While the water quality is qualified, a large amount of sludge containing arsenic and other heavy metals is also produced, which is then transported to a landfill for disposal. Although this method is simple, it has many shortcomings. It not only consumes a lot of manpower, material resources, and financial resources to build a landfill, but also occupies a large amount of land; the landfill is easily affected by natural disasters such as earthquakes, causing the leakage of hazardous waste leachate containing arsenic and other heavy metals in the landfill and polluting the environment; the use of cement or other processes has factors such as high cost and unstable leaching toxicity. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a method for solidifying arsenic in high-arsenic sludge using clay and copper slag. The method uses high-arsenic sludge, clay, and copper slag as main raw materials. The roasted product under a protective atmosphere can be safely stored or used as roadbed materials, etc.

[0005] In order to achieve the above technical objectives, the present invention is implemented through the following technical solutions:

[0006] A method for solidifying arsenic in high-arsenic sludge using clay and copper slag comprises the following steps:

[0007] S1: Pre-treating high-arsenic sludge, clay, and copper slag to obtain dry material, dry clay powder, and copper slag powder;

[0008] S2: uniformly mixing the dry material obtained in step S1, dry clay powder, copper slag powder, and coal powder, adding water and stirring at room temperature for a pre-reaction, and then pouring into a crucible to obtain a paste mixture A;

[0009] S3: After the mixture A obtained in step S2 is naturally dried, it is placed in a protective atmosphere for roasting.

[0010] Furthermore, the step S1 specifically includes the following sub-steps:

[0011] S1.1: Dry and grind the high-arsenic sludge to obtain dry material;

[0012] S1.2: drying and grinding the clay to obtain dry clay powder;

[0013] S1.3: Ball-mill the copper slag to obtain copper slag powder.

[0014] Furthermore, the drying operation of the high-arsenic sludge in step S1.1 is specifically drying at 105°C for 12 hours, and the grinding operation is specifically grinding the dried high-arsenic sludge to a particle size of less than 0.5 mm; the drying operation of the clay in step S1.2 is specifically air-drying, and the grinding operation is specifically crushing and grinding to pass through a 100-mesh sieve; the ball milling operation of the copper slag in step S1.3 is specifically ball milling to pass through a 200-mesh sieve.

[0015] Furthermore, the pre-reaction time in step S2 is 6 hours.

[0016] Furthermore, in step S2, the mass ratio of the dry material to the dry clay powder, copper slag powder, and coal powder is 6: (6-10): (3-5): (0.15-0.25).

[0017] Furthermore, the calcination environment temperature in step S3 is 850-900° C., and the calcination time is 20-40 minutes.

[0018] Furthermore, the arsenic content of the arsenic-containing gypsum slag in step S1 is 11.56-11.88 wt%.

[0019] Furthermore, the coal powder in step S2 is coking coal or anthracite.

[0020] Furthermore, the amount of water added in step S2 is 50% of the mass of mixture A.

[0021] Furthermore, the protective atmosphere in step S3 is nitrogen.

[0022] The beneficial effects of the present invention are:

[0023] The present invention relates to a method for solidifying arsenic in high-arsenic sludge using clay and copper slag. This method is applicable to heavy metal pollution control and comprehensive resource utilization. After natural cooling, the reaction product is used as roadbed material, etc. This method utilizes clay and copper slag for the treatment of high-arsenic sludge by roasting, resulting in low toxicity and excellent stability of arsenic and other heavy metal leaching, while also fully utilizing metallurgical solid waste.

[0024] The present invention adopts high-temperature calcination in a non-oxidizing atmosphere during the stabilization process, so that the internal structure of the solid product is more stable and the heavy metal toxicity is lower. Since the clay itself has solidification properties, the amount of cement used can be reduced, thereby reducing the consumption of natural resources.

[0025] The raw materials of the present invention are low in price, highly adaptable, and simple to operate. The roasted products can be used for roadbed materials and mine backfill, etc., greatly reducing the cost of high-arsenic sludge disposal and being relatively easy to promote and apply.

[0026] The method proposed in the present invention not only reduces the stockpiles of high-arsenic sludge and copper slag and the cost of building landfills, but also avoids the risk of environmental pollution, thereby achieving the purpose of protecting the environment and increasing the economic benefits of non-ferrous metal smelting enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a process flow chart of the present invention;

[0029] Figure 2 This is a schematic diagram of the process from raw materials to finished products of the present invention. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figure 1 shown

[0033] As described in this embodiment, a method for solidifying arsenic in high-arsenic sludge using clay and copper slag includes the following steps:

[0034] S1: Pre-treating high-arsenic sludge, clay, and copper slag to obtain dry material, dry clay powder, and copper slag powder;

[0035] S2: uniformly mixing the dry material obtained in step S1, dry clay powder, copper slag powder, and coal powder, adding water and stirring at room temperature for a pre-reaction, and then pouring into a crucible to obtain a paste mixture A;

[0036] S3: After the mixture A obtained in step S2 is naturally dried, it is placed in a protective atmosphere for roasting.

[0037] In this embodiment, step S1 specifically includes the following sub-steps:

[0038] S1.1: Dry and grind the high-arsenic sludge to obtain dry material;

[0039] S1.2: drying and grinding the clay to obtain dry clay powder;

[0040] S1.3: Ball-mill the copper slag to obtain copper slag powder.

[0041] In this embodiment, the drying operation of the high-arsenic sludge in step S1.1 is specifically drying at 105°C for 12 hours, and the grinding operation is specifically grinding the dried high-arsenic sludge to a particle size of less than 0.5 mm; the drying operation of the clay in step S1.2 is specifically air-drying, and the grinding operation is specifically crushing and grinding to pass through a 100-mesh sieve; the ball milling operation of the copper slag in step S1.3 is specifically ball milling to pass through a 200-mesh sieve.

[0042] In this embodiment, the pre-reaction time in step S2 is 6 hours.

[0043] In this embodiment, the mass ratio of the dry material to the dry clay powder, copper slag powder, and coal powder in step S2 is 6: (6-10): (3-5): (0.15-0.25).

[0044] In this embodiment, the ambient temperature for calcination in step S3 is 850-900° C., and the calcination time is 20-40 minutes.

[0045] In this embodiment, the arsenic content of the high-arsenic sludge in step S1 is 11.56-11.88 wt%.

[0046] In this embodiment, the pulverized coal in step S2 is coking coal or anthracite.

[0047] In this embodiment, the amount of water added in step S2 is 50% of the mass of mixture A.

[0048] In this embodiment, the protective atmosphere in step S3 is nitrogen.

[0049] Example 2

[0050] like Figure 1 As shown, the method for solidifying arsenic in high-arsenic sludge using clay and copper slag has the following specific steps:

[0051] (1) High arsenic sludge (the main element content of high arsenic sludge is shown in Table 1 and the leaching toxicity is shown in Table 4) was dried at 105 ° C for 12 hours and ground to a particle size of less than 0.5 mm to obtain a dry material

[0052] Table 1

[0053] element Ca S As Fe Zn Cu Cd Content wt% 27.36 14.32 11.88 1.52 0.45 0.14 0.1

[0054] (2) The clay (the main phases and elements of the clay are shown in Table 2) was naturally air-dried, crushed and ground through a 100-mesh sieve to obtain dry clay powder;

[0055] Table 2

[0056]

[0057] (3) The copper slag (the main element content of the copper slag is shown in Table 3) was ball-milled through a 200-mesh sieve to obtain copper slag powder;

[0058] Table 3

[0059] element Fe O Si AI Mg Zn Ca K S Content wt% 45.73 22.4 14.92 2.74 1.04 1.59 3.25 0.84 0.14

[0060] (4) Ingredients: The dry material obtained in step S1, dry clay powder, copper slag powder, and coal powder were mixed uniformly in a mass ratio of 6:10:5:0.15 to obtain a mixture A, 50% water was added, and the mixture was stirred at room temperature for a pre-reaction for 6 hours, and then poured into a crucible to obtain a paste-like mixture A;

[0061] (5) Calcination: After the mixture A obtained in step S2 is naturally dried, it is placed in a protective atmosphere and calcined at a temperature of 900°C for 20 minutes. The protective gas contained in the tail gas after deep purification treatment by gas washing can be recycled, and the reaction product is sent to the yard or used as road subgrade materials, etc.

[0062] The leaching toxicity test was conducted on the high-arsenic sludge and solidified product of this example. The results are shown in Table 4.

[0063] Table 4

[0064] element As Zn Pb Cd Cu High arsenic sludge / mg / L 3790 1.77 — 0.61 — After curing / mg / L 0.5 — — — — GB5085.3-2007 / mg / L 5 100 5 1 100 GB18598-2019 / mg / L 1.2 120 1.2 0.6 120

[0065] Note: “-” indicates not detected.

[0066] The leaching concentration of heavy metal elements in the reaction product obtained by the solidification treatment of this embodiment meets the requirements of the "Hazardous Waste Identification Standard Leaching Toxicity Identification" (GB5085.3-2007) and the "Hazardous Waste Landfill Pollution Control Standard" (GB18598-2019), and the finished product can be safely stored or used.

[0067] Example 3

[0068] like Figure 1 As shown, the method for solidifying arsenic in high-arsenic sludge using clay and copper slag has the following specific steps:

[0069] (1) High arsenic sludge (the main element content of high arsenic sludge is shown in Table 5 and the leaching toxicity is shown in Table 8) was dried at 105°C for 12 hours and ground to a particle size of less than 0.5 mm to obtain a dry material.

[0070] Table 5

[0071] element Ca S As Fe Zn Cu Cd Content wt% 28.56 14.95 11.56 1.54 0.43 0.13 0.09

[0072] (2) The clay (the main phases and elements of the clay are shown in Table 6) was naturally air-dried, crushed and ground through a 100-mesh sieve to obtain dry clay powder;

[0073] Table 6

[0074]

[0075]

[0076] (3) The copper slag (the main element content of the copper slag is shown in Table 7) was ball-milled through a 200-mesh sieve to obtain copper slag powder;

[0077] Table 7

[0078] element Fe O Si AI Mg Zn Ca K S Content wt% 45.65 2153 14.22 2.85 0.96 1.45 2.98 0.73 0.23

[0079] (4) Ingredients: The dry material obtained in step S1, dry clay powder, copper slag powder, and coal powder were mixed uniformly in a mass ratio of 6:8:4:0.2 to obtain a mixture A, 50% water was added, and the mixture was stirred at room temperature for a pre-reaction for 6 hours, and then poured into a crucible to obtain a paste-like mixture A;

[0080] (5) Calcination: After the mixture A obtained in step S2 is naturally dried, it is placed in a protective atmosphere and calcined at a temperature of 875°C for 30 minutes. The protective gas contained in the tail gas after deep purification treatment by gas washing can be recycled, and the reaction product is sent to the yard or used as road subgrade materials, etc.

[0081] The leaching toxicity test was conducted on the high-arsenic sludge and solidified product of this example. The results are shown in Table 8.

[0082] Table 8

[0083] element As Zn Pb Cd Cu High arsenic sludge / mg / L 3900 1.78 — 0.65 — After curing / mg / L 0.79 — — — — GB5085.3-2007 / mg / L 5 100 5 1 100 GB18598-2019 / mg / L 1.2 120 1.2 0.6 120

[0084] Note: “-” indicates not detected.

[0085] The leaching concentration of heavy metal elements in the reaction product obtained by the solidification treatment of this embodiment meets the requirements of the "Hazardous Waste Identification Standard Leaching Toxicity Identification" (GB5085.3-2007) and the "Hazardous Waste Landfill Pollution Control Standard" (GB18598-2019), and the finished product can be safely stored or used.

[0086] Example 4

[0087] like Figure 1 As shown, the method for solidifying arsenic in high-arsenic sludge using clay and copper slag has the following specific steps:

[0088] (1) High arsenic sludge (the main element content of high arsenic sludge is shown in Table 9 and the leaching toxicity is shown in Table 12) was dried at 105 ° C for 12 hours and ground to a particle size of less than 0.5 mm to obtain a dry material

[0089] Table 9

[0090] element Ca S As Fe Zn Cu Cd Content wt% 27.94 14.64 11.72 1.53 0.44 0.14 0.1

[0091] (2) The clay (the main phases and elements of the clay are shown in Table 10) was naturally air-dried, crushed and ground through a 100-mesh sieve to obtain dry clay powder;

[0092] Table 10

[0093]

[0094] (3) The copper slag (the main element content of the copper slag is shown in Table 11) was ball-milled through a 200-mesh sieve to obtain copper slag powder;

[0095] Table 11

[0096] element Fe O Si AI Mg Zn Ca K S Content wt% 45.69 21.96 14.56 2.8 0.99 1.52 3.11 0.79 0.19

[0097] (4) Ingredients: The dry material obtained in step S1, dry clay powder, copper slag powder, and coal powder were mixed uniformly in a mass ratio of 6:6:3:0.25 to obtain a mixture A, 50% water was added, and the mixture was stirred at room temperature for a pre-reaction for 6 hours, and then poured into a crucible to obtain a paste-like mixture A;

[0098] (5) Calcination: After the mixture A obtained in step S2 is naturally dried, it is placed in a protective atmosphere and calcined at a temperature of 850°C for 40 minutes. The protective gas contained in the tail gas after deep purification by gas washing can be recycled, and the reaction product is sent to the yard or used as road subgrade materials, etc.

[0099] The leaching toxicity test was conducted on the high-arsenic sludge and solidified product of this example. The results are shown in Table 12.

[0100] Table 12

[0101] element As Zn Pb Cd Cu High arsenic sludge / mg / L 4033 1.79 — 0.7 — After curing / mg / L 0.63 — — — — GB5085.3-2007 / mg / L 5 100 5 1 100 GB18598-2019 / mg / L 1.2 120 1.2 0.6 120

[0102] Note: “-” indicates not detected.

[0103] The leaching concentration of heavy metal elements in the reaction product obtained by the solidification treatment of this embodiment meets the requirements of the "Hazardous Waste Identification Standard Leaching Toxicity Identification" (GB5085.3-2007) and the "Hazardous Waste Landfill Pollution Control Standard" (GB18598-2019), and the finished product can be safely stored or used.

[0104] Example 5

[0105] like Figure 2As shown, high-arsenic sludge, clay, copper slag, and coal powder are mixed in proportion and 50% water is added. The mixture is stirred at room temperature for a pre-reaction of 6 hours. The mixture is poured into a crucible for shaping. After natural drying, it is sent into a protective atmosphere for roasting to obtain a solidified product.

[0106] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0107] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for solidifying arsenic in high-arsenic sludge using clay and copper slag, characterized by: The following steps are involved: S1: Pre-treating high-arsenic sludge, clay, and copper slag to obtain dry material, dry clay powder, and copper slag powder; S2: uniformly mixing the dry material obtained in step S1, dry clay powder, copper slag powder, and coal powder, adding water and stirring at room temperature for a pre-reaction, and then pouring into a crucible to obtain a paste mixture A; S3: After the mixture A obtained in step S2 is naturally dried, it is placed in a protective atmosphere for roasting; The step S1 specifically comprises the following sub-steps: S1.1: Dry and grind the high-arsenic sludge to obtain dry material; S1.2: drying and grinding the clay to obtain dry clay powder; S1.3: ball milling the copper slag to obtain copper slag powder; In step S1.1, the drying operation of the high-arsenic sludge is specifically drying at 105° C. for 12 hours, and the grinding operation is specifically grinding the dried high-arsenic sludge to a particle size of less than 0.5 mm; in step S1.2, the drying operation of the clay is specifically air-drying, and the grinding operation is specifically crushing and grinding to pass through a 100-mesh sieve; in step S1.3, the ball milling operation of the copper slag is specifically ball milling to pass through a 200-mesh sieve; The pre-reaction time in step S2 is 6 hours; the mass ratio of the dry material to the dry clay powder, copper slag powder, and coal powder in step S2 is 6: (6-10): (3-5): (0.15-0.25); The ambient temperature for calcination in step S3 is 850-900° C., and the calcination time is 20-40 minutes.

2. The method for solidifying arsenic in high-arsenic sludge using clay and copper slag according to claim 1, characterized in that: The arsenic content of the high-arsenic sludge in step S1 is 11.56-11.88 wt %.

3. The method for solidifying arsenic in high-arsenic sludge using clay and copper slag according to claim 1, characterized in that: The pulverized coal is coking coal or anthracite.

4. The method for solidifying arsenic in high-arsenic sludge using clay and copper slag according to claim 1, characterized in that: The amount of water added in step S2 is 50% of the mass of mixture A.

5. The method for solidifying arsenic in high-arsenic sludge using clay and copper slag according to claim 1, characterized in that: The protective atmosphere in step S3 is nitrogen.

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