Sulfur-resistant and high-temperature-resistant gaseous arsenic adsorption material, and preparation method and application thereof

Abstract

The application relates to a sulfur-resistant and high-temperature-resistant gaseous arsenic adsorption material and a preparation method and application thereof, and belongs to the gaseous arsenic adsorption field. The adsorption material is prepared by activating lithium slag through mechanical ball milling. The material has a large adsorption capacity and low cost, application of the material can reduce the emission of gaseous arsenic of non-ferrous smelting enterprises, meanwhile, the storage of lithium slag in the lithium carbonate industry is reduced, and resource utilization is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gaseous arsenic adsorption, in particular to a sulfur-tolerant and high-temperature-resistant gaseous arsenic adsorption material and its preparation method and application. BACKGROUND

[0002] Non-ferrous smelting is the main human source of atmospheric arsenic emissions. During non-ferrous smelting, most of the arsenic is volatilized into flue gas. The arsenic in the flue gas entering the subsequent section not only reduces the grade of by-product sulfuric acid, but also part of the arsenic is released into the environment with the flue gas, bringing huge environmental risks. Existing studies have shown that using adsorbents to capture gaseous arsenic in flue gas is an effective means to control atmospheric arsenic pollution. Compared with wet scrubbing process, solid-phase adsorption has the advantages of simple process and no impact on the quality of subsequent by-products. In addition, arsenic resources can be effectively recovered from used adsorbents. At present, many metal oxides, such as manganese oxide, iron oxide, calcium oxide, etc. are used for gaseous arsenic adsorption. However, these adsorbents have problems such as high price, low adsorption capacity, poor SO2 tolerance, etc.

[0003] The process of lithium carbonate production has traditional limestone calcination method and widely used sulfuric acid method, sulfate method and chlorination calcination method, in addition, new technologies such as alkali dissolution method, pressure cooking method and composite salt calcination have also been developed. Lithium ore is prepared by batching, high-temperature calcination and leaching, and lithium is extracted into the solution. The lithium extraction leaching residue (hereinafter referred to as lithium residue) is stacked in the plant. Lithium residue is an industrial silicon-aluminum waste residue. 8-10 tons of lithium residue are discharged for every ton of Li2CO3 produced. Lithium residue is a large amount of solid waste inevitably produced in the lithium extraction process, and faces problems such as large stacking amount and difficult resource utilization.

[0004] Lithium residue, as an aluminosilicate rich in alkali metal elements, has excellent potential for adsorbing gaseous arsenic. If lithium residue is used as raw material to develop an adsorption material to adsorb gaseous arsenic in flue gas, it can not only solve the problem of lithium residue resource utilization, but also provide an easy-to-operate and low-cost method for efficient treatment of gaseous arsenic. SUMMARY

[0005] In view of the existing problems of difficult lithium residue resource utilization and difficult removal of gaseous arsenic, the present application uses lithium residue to prepare a sulfur-tolerant and high-temperature-resistant gaseous arsenic adsorption material and realizes its application. The preparation method is simple and the cost is low. At the same time, the lithium residue can be resourceized, providing a feasible way for lithium residue disposal.

[0006] To achieve the above purpose, the present application provides a sulfur-tolerant and high-temperature-resistant gaseous arsenic adsorption material, which is prepared by mechanical ball milling and activation of lithium residue. Preferably, the arsenic adsorption capacity is greater than 13 mg / g. More preferably, in the process of mechanical ball milling and activation, the phase of lithium residue is changed from smoky quartz to nepheline and hauyne; the degree of amorphization increases.

[0007] Preferably, the ball milling time is 75-175 min; the ball milling rotation speed is 300-600 r / min; and the ball-to-material mass ratio is 4:1-10:1.

[0008] Preferably, the method further comprises adding an auxiliary material during the ball milling; the auxiliary material is one or more of hydroxides, carbonates or bicarbonates of lithium, sodium or potassium.

[0009] Preferably, the mass ratio of the auxiliary material to the lithium residue is 1:10-1:6.

[0010] The application also provides a preparation method of the gaseous arsenic adsorption material as described above, which comprises: mechanically ball-milling and activating the lithium residue.

[0011] Preferably, the ball milling time is 75-175 min; the ball milling rotation speed is 300-600 r / min; and the ball-to-material mass ratio is 4:1-10:1.

[0012] Preferably, the method further comprises adding an auxiliary material during the ball milling; the auxiliary material is one or more of hydroxides, carbonates or bicarbonates of lithium, sodium or potassium.

[0013] Preferably, the mass ratio of the auxiliary material to the lithium residue is 1:10-1:6.

[0014] The application also provides an application of the gaseous arsenic adsorption material as described above as an adsorbent in the treatment of arsenic-containing flue gas.

[0015] Preferably, the temperature of the adsorption process is 400-600 DEG C.

[0016] Preferably, the sulfur dioxide content in the arsenic-containing flue gas is 0-10%.

[0017] Preferably, the adsorption time is 30-90 min.

[0018] The technical key of the application is to mechanically ball-mill and activate the lithium residue, thereby enhancing the adsorption performance thereof. The mechanical ball-milling is to make the grinding balls and the materials collide, shear and rub in the tank body by rotating the drum, so as to achieve the effects of material crushing, mixing and surface activity enhancement. In this process, the hydroxyl ions in the auxiliary material attack the aluminum silicate skeleton during the ball milling, thereby promoting the phase transformation and increasing the reactivity of the lithium residue; and the auxiliary material can also act as a grinding aid during the ball milling.

[0019] The application dries the lithium residue, then mechanically ball-mills and activates the same, and uses the obtained sample as an adsorbent to adsorb gaseous arsenic, thereby effectively controlling the emission of gaseous arsenic in non-ferrous smelting enterprises, and providing a new resource utilization approach for the disposal of lithium residue in the lithium carbonate industry.

[0020] Compared with the prior art, the application has the following advantages:

[0021] The mechanical ball milling activated lithium residue can increase the specific surface area, amorphous degree and reaction activity of the lithium residue, is simple in operation, and has high temperature resistance, sulfur resistance and large gaseous arsenic adsorption capacity.

[0022] The present application provides a new way for lithium residue disposal by recycling lithium extraction leaching residue.

[0023] The preparation method of the gaseous arsenic adsorption material is suitable for large-scale preparation of enterprises and conforms to the actual production. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is the adsorption effect of gaseous arsenic of the adsorbent prepared in Example 1 under different ball milling times;

[0025] Figure 2 The figure is the adsorption effect of gaseous arsenic of the adsorbent prepared in Example 2 under different ball milling speeds;

[0026] Figure 3 The figure is the adsorption effect of gaseous arsenic of the adsorbent prepared in Example 3 under different ball milling ratios;

[0027] Figure 4 The figure is the adsorption effect of gaseous arsenic of the adsorbent prepared in Example 4 under different auxiliary material ratios;

[0028] Figure 5 The figure is the adsorption effect of gaseous arsenic of the adsorbent prepared in Example 5 under different sulfur dioxide concentrations;

[0029] Figure 6 The figure is the adsorption effect of gaseous arsenic under different adsorption temperatures in Example 6;

[0030] Figure 7 The figure is the comparison of the adsorption effect of gaseous arsenic of different adsorption materials under the same adsorption temperature and atmosphere;

[0031] Figure 8 The figure is the XRD pattern of the lithium residue without ball milling, the lithium residue after ball milling without auxiliary material and the lithium residue after ball milling with auxiliary material in Example 8. DETAILED DESCRIPTION

[0032] The technical solutions of the present application are further described below by specific examples in combination with the drawings. It should be noted that the reagents, raw materials, instruments and equipment involved in the present application are all ordinary commercially available products, and the lithium residue used in the present application is the lithium residue stored by a lithium carbonate production company in Jiangxi. The elemental composition of the lithium residue is shown in Table 1. In the examples of the present application, NaOH is used as an example for the auxiliary material, and it can be understood that other auxiliary materials can also achieve the same or similar technical effects.

[0033] Table 1 Elemental composition of lithium residue

[0034] ,

[0035] *Rb, Cs were tested by digestion-ICP

[0036] Example 1: Set the ball milling speed to 450 rpm, ball-to-material ratio to 6:1, without auxiliary material, and ball milling time to 25, 75, 125, and 175 min, respectively. 10 g of lithium slag was added and ball milled. The obtained sample was dried and 0.1 g of the sample was placed in the gaseous arsenic adsorption system. The adsorption conditions were as follows: adsorption temperature 400 ℃, atmosphere (O2 25%, Ar 87%, SO2 25%, CO2 23%), and adsorption time 30 min.

[0037] The gaseous arsenic adsorption system is described as follows: The system consists of a hydrogen arsenide generator, an adsorption reactor, and a tail gas treatment system. The hydrogen arsenide generator generates hydrogen arsenide, which enters the two-stage reaction furnace. The hydrogen arsenide is oxidized to diarsenic trioxide in the first-stage reaction furnace, and the diarsenic trioxide enters the second-stage reaction furnace for adsorption reaction. The tail gas is discharged after passing through two tail gas absorption bottles. The simulated flue gas components are O2 25%, Ar 87%, SO2 25%, and CO2 23%, the flue gas flow rate is 400 ml / min, and the As2O3 concentration in the simulated flue gas is 0.6 mg / L.

[0038] As shown in Table 1, when the ball milling time is 125 min, the gaseous arsenic adsorption capacity reaches 5.4 mg / g. When the ball milling time exceeds 125 min, the particles will agglomerate, and the adsorption capacity will decrease. Figure 1

[0039] Example 2: Set the ball milling time to 25 min, ball-to-material ratio to 6:1, without auxiliary material, and ball milling speed to 0, 300, 400, 500, 600, and 700 rpm, respectively. The obtained sample was dried and 0.1 g of the sample was placed in the gaseous arsenic adsorption system for experiment. The adsorption conditions were as follows: adsorption temperature 400 ℃, atmosphere (O2 25%, Ar 87%, SO2 25%, CO2 23%), and adsorption time 30 min.

[0040] As shown in Table 2, when the ball milling speed reaches 600 rpm, the gaseous arsenic adsorption capacity is the largest, which is 6.80 mg / g. When the ball milling speed continues to increase, the arsenic adsorption capacity decreases, which is due to the agglomeration of particles caused by excessive ball milling speed. Figure 2

[0041] Example 3: Set the ball milling time to 125 min, ball milling speed to 600 rpm, and ball-to-material ratio to 4:1, 6:1, 8:1, and 10:1, respectively. The obtained sample was dried and 0.1 g of the sample was placed in the gaseous arsenic adsorption system for experiment. The adsorption conditions were as follows: adsorption temperature 400 ℃, atmosphere (O2 25%, Ar 87%, SO2 25%, CO2 23%), and adsorption time 30 min.

[0042] As shown in Table 3, when the ball-to-material ratio is 6:1, the gaseous arsenic adsorption capacity is the largest, which is 6.80 mg / g. When the ball-to-material ratio continues to increase, the arsenic adsorption capacity decreases, which is due to the agglomeration of particles caused by excessive ball milling speed. Figure 3 ​​When the ball-to-material ratio is 10:1, the adsorption capacity of gaseous arsenic reaches 13.68 mg / g.

[0043] Example 4: The ball milling time was set to 125 min, the ball-to-material ratio to be 10:1, and the ball milling speed to be 600 rpm. NaOH was selected as the auxiliary material, with auxiliary material to main material ratios of 0, 1:6, 2:6, 3:6, and 5:6. After drying, 0.1 g of the obtained sample was weighed and placed in a gaseous arsenic adsorption system for the experiment. Adsorption conditions: adsorption temperature 400℃, atmosphere (O2 5%, Ar 87%, SO2 5%, CO2 3%), adsorption time 30 min.

[0044] like Figure 4 The adsorption capacity of gaseous arsenic reached its maximum of 19.26 mg / g when the excipient ratio was 1:6. As the excipient ratio continued to increase, the adsorption capacity decreased rapidly because the excessive amount of NaOH added caused the particles to clump together.

[0045] Example 5: The ball milling speed was set to 600 rpm, the ball-to-material ratio to be 10:1, no auxiliary materials were used, and the ball milling time was 125 min. The SO2 concentrations were 0%, 5%, and 10% respectively. After drying, 0.1 g of the obtained sample was weighed and placed in a gaseous arsenic adsorption system for the experiment. Adsorption conditions: adsorption temperature 400℃, atmosphere (O2 5%, Ar 82%-92%, SO2 0%-10%, CO2 3%), adsorption time 30 min.

[0046] Depend on Figure 5 It can be seen that low concentrations of SO2 promote arsenic adsorption. When the SO2 concentration is 5%, the adsorption capacity of gaseous arsenic reaches 13.68 mg / g.

[0047] Example 6: The ball milling time was set to 125 min, the ball-to-material ratio to be 10:1, the ball milling speed to be 600 rpm, and no auxiliary materials were used. The adsorption temperatures were 400, 500, and 600 °C. After drying, 0.1 g of the obtained sample was weighed and placed in a gaseous arsenic adsorption system for the experiment. Adsorption conditions: adsorption temperature 400-800 °C, atmosphere (O2 5%, Ar 87%, SO2 5%, CO2 3%), adsorption time 30 min.

[0048] Depend on Figure 6 As can be seen, the adsorption capacity of gaseous arsenic gradually increases with increasing temperature, reaching a maximum of 15.85 mg / g at 600℃.

[0049] Example 7: The ball milling time was set to 125 min, the ball-to-material ratio to be 10:1, the ball milling speed to be 600 rpm, and NaOH was selected as the excipient with an excipient ratio of 1:6. After drying, 0.1 g of the obtained sample was weighed and placed in a gaseous arsenic adsorption system for the experiment. Adsorption conditions: adsorption temperature 600℃, atmosphere (O2 5%, Ar 87%, SO2 5%, CO2 3%), adsorption time 30 min.

[0050] As Figure 7 , the gaseous arsenic adsorption capacity of the ball-milled lithium slag can reach 21.64 mg / g, which has excellent gaseous arsenic adsorption capacity.

[0051] Example 8: XRD analysis was performed on untreated lithium slag, ball-milled lithium slag without additives (ball milling time 125 min, ball-to-material ratio 10:1, ball milling speed 600 rpm), and ball-milled lithium slag with additives (ball milling time 125 min, ball-to-material ratio 10:1, ball milling speed 600 rpm, additive selected as NaOH, additive ratio 1:6).

[0052] As Figure 8 , after ball milling, the main phase of the lithium slag changes from lapis lazuli to nepheline, and various minerals such as kyanite, and the mineral diversity increases, and the amorphous degree increases from 28% to nearly 40%.

[0053] Comparative Example 1: 0.1 g of untreated lithium slag was weighed into the gaseous arsenic adsorption system. Adsorption conditions: adsorption temperature 600℃, atmosphere (O25%, Ar 87%, SO25%, CO23%), adsorption time 30 min.

[0054] As Figure 7 , the gaseous arsenic adsorption capacity of the untreated lithium slag is 1.85 mg / g, which is only 1 / 12 of that of the ball-milled and optimized lithium slag.

[0055] Comparative Example 2: 0.1 g of CaO was weighed into the gaseous arsenic adsorption system. Adsorption conditions: adsorption temperature 600℃, atmosphere (O25%, Ar 87%, SO25%, CO23%), adsorption time 30 min.

[0056] As Figure 7 , the gaseous arsenic adsorption capacity of calcium oxide is 5.3 mg / g, which is only 1 / 4 of that of the ball-milled and optimized lithium slag.

[0057] The present application prepares a high-temperature-resistant and sulfur-resistant gaseous arsenic adsorbent by mechanically activating lithium leaching residue, which has the advantages of simple method, low cost, and resource utilization of lithium slag which is difficult to handle for lithium carbonate enterprises.

[0058] The above examples are only preferred embodiments of the present application, and the protection scope of the present application is not limited to the above examples. Any technical solutions falling within the concept of the present application shall fall within the protection scope of the present application. It should be noted that improvements and refinements made by ordinary skilled persons in the art without departing from the principles of the present application shall also be considered within the protection scope of the present application.

Claims

1. Use of a sulfur and high temperature resistant gaseous arsenic adsorbent material as an adsorbent in the treatment of arsenic containing flue gases, characterized in that, The temperature of the adsorption process is 400-600℃; the content of sulfur dioxide in the arsenic-containing flue gas is 0-10%, not 0; the adsorption time is 30-90 min; the sulfur-tolerant and high-temperature-resistant gaseous arsenic adsorption material is prepared from lithium residue by mechanical ball milling activation, in the mechanical ball milling activation process, the phase of the lithium residue is changed from smoky quartz to nepheline and hauyne; the ball milling time is 75-175 min; the ball milling rotation speed is 300-600 r / min; the mass ratio of ball to material is 4:1-10:1; an auxiliary material is added in the ball milling process; the auxiliary material is one or more of lithium, sodium or potassium hydroxide, carbonate or bicarbonate; the mass ratio of the auxiliary material to the lithium residue is 1:10-1:6.

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