Mine pit repairing material as well as preparation method and application thereof

Abstract

The invention discloses a pit repairing material as well as a preparation method and application thereof, and belongs to the technical field of environment repairing materials. The mine pit repairing material is prepared from the fresh phosphogypsum, the storage yard phosphogypsum, the phosphorite tailings and the like, the purpose of recycling the phosphogypsum can be achieved, the stockpiling amount of the phosphogypsum can be effectively reduced, and therefore the problems of land waste and environmental pollution occurring in the stockpiling process are avoided. The mine pit repairing material prepared by adopting the preparation method disclosed by the invention is relatively low in pollutant content, and can effectively avoid adverse effects on the environment. The mine pit repairing material prepared by the preparation method has excellent mechanical properties, and can effectively ensure the stability of a repaired mine pit.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental restoration materials, and in particular relates to a mine restoration material and a preparation method and application thereof. Background Art

[0002] Mining is an important part of human economic development, however, it also causes serious damage to the environment. During the mining process, the soil is excavated and disturbed, leading to environmental problems such as soil erosion, soil erosion and loss of biodiversity. Traditional mine remediation methods mainly include soil improvement and vegetation restoration. However, these methods cannot restore the mine to its original landform, are prone to water accumulation, and geological disasters such as collapse occur. There are also some limitations in restoring the ecosystem function of the mining area.

[0003] Phosphogypsum is a byproduct of wet phosphoric acid production. Every ton of phosphoric acid (100% P2O5) produced will produce 3 to 5 tons of phosphogypsum. According to the requirements of relevant national standards for environmental pollution control, the components in phosphogypsum that may cause environmental pollution risks mainly include: acidic (low pH, generally 2.3 to 5.5) substances, soluble phosphorus, fluorine and heavy metals. At present, there are two main ways to dispose of phosphogypsum: storage and comprehensive utilization. When phosphogypsum is stored, its soluble phosphorus, fluorine and heavy metals will leach into related water bodies with natural rainfall, bringing environmental pollution risks. Therefore, harmless treatment of phosphogypsum, optimization of formula, improvement of material performance, reduction of environmental pollution risks, and large-scale utilization of phosphogypsum for the preparation of surface mine filling and ecological restoration materials are of great significance for filling, repairing and managing a large number of existing surface mines in China, protecting the environment, and achieving sustainable and healthy development of the phosphorus chemical industry.

[0004] At present, the harmless treatment of phosphogypsum is mainly based on chemical treatment and water washing methods. Chemical treatment is to add specific substances to react with soluble phosphorus, fluorine and heavy metals in phosphogypsum to form insoluble or insoluble compounds to achieve passivation and fixation. This method has good treatment effect, but the cost is high. The water washing method has a low cost, but the removal effect of certain harmful impurities is limited, and the washing liquid generated needs to be optimized. Summary of the invention

[0005] In view of the above-mentioned prior art, the present invention provides a mine repair material and a preparation method and application thereof, so as to solve the technical problems of difficulty in mine repair and difficulty in recycling phosphogypsum.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is to provide a method for preparing a mine repair material, comprising the following steps: S1: Mix fresh phosphogypsum with water at a material-liquid ratio of 1kg:3~5L, add a flotation agent to the mixture, then stir and aerate for 8~15min, then let it stand for 5~15min, remove the upper water layer, collect the bottom phosphogypsum, add quicklime and polyaluminium chloride after dehydration by filter pressing, mix well and store for aging for 15~30 days to obtain harmless fresh phosphogypsum; S2: crushing the phosphogypsum in the stockpile into powder with a particle size not exceeding 10 μm, then mixing the obtained phosphogypsum powder in the stockpile with quicklime, polyaluminium chloride and a heavy metal chelating agent, and then stockpiling and aging the mixture for 30 to 90 days to obtain harmless stockpiled phosphogypsum; S3: crushing the phosphate tailings with a phosphorus pentoxide content of less than 5% into particles with a particle size of 20-100 μm to obtain aggregate; S4: uniformly mixing harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cementitious material in a mass ratio of 0-90:0-90:0-10:0-5 to obtain a mixture; the cementitious material is cement or gypsum powder; S5: Load the mixture into a mold, press at a pressure of 30-40 MPa for 0.5-20 min, then demold and cure outdoors for 2-15 days.

[0007] Based on the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, the amount of flotation agent added is 0-0.01‰ of the mass of fresh phosphogypsum; the flotation agent is sodium dodecylbenzene sulfonate.

[0009] Furthermore, the amounts of quicklime and polyaluminium chloride added in S1 are 1-5% and 0-1‰ of the mass of the phosphogypsum after filter pressing and dehydration, respectively.

[0010] Furthermore, the mass ratio of the phosphogypsum powder, quicklime, polyaluminium chloride and heavy metal chelating agent in the yard is 100:3~5:0.1:0.1~0.5.

[0011] Furthermore, the heavy metal chelating agent is a dithiocarbamate.

[0012] Furthermore, the stockpiling aging time in S2 is 60 days.

[0013] Furthermore, the mass ratio of harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cementitious material is 45:45:5:5.

[0014] Furthermore, in S5, the pressing pressure is 40 MPa, the pressing time is 20 min, and the curing time is 10 days.

[0015] The invention also discloses a mine repair material, which is prepared by adopting the preparation method.

[0016] The invention also discloses the application of the mine pit repair material in mine pit repair.

[0017] The beneficial effects of the present invention are: 1. The mine repair material in the present invention is prepared with fresh phosphogypsum, stockpile phosphogypsum and phosphate ore tailings as raw materials, which can achieve the purpose of recycling phosphogypsum and effectively reduce the stockpile of phosphogypsum, thereby avoiding land waste and environmental pollution problems caused by the stockpile process.

[0018] 2. The mine repair material prepared by the preparation method of the present invention has a low pollutant content and can effectively avoid adverse effects on the environment.

[0019] 3. The mine repair material prepared by the preparation method of the present invention has excellent mechanical properties and can effectively ensure the stability of the mine after repair. DETAILED DESCRIPTION

[0020] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0021] Example 1 A mine repair material is prepared by the following steps: S1: Mix fresh phosphogypsum and water at a material-liquid ratio of 1kg:4L, add sodium dodecylbenzene sulfonate to the mixture as a flotation agent, and the amount of sodium dodecylbenzene sulfonate added is 0.01‰ of the mass of the fresh phosphogypsum; then stir at a stirring rate of 60rpm, and blow air in during the stirring process for 10min, then let it stand for 10min, the phosphogypsum precipitates to the lower layer, the upper layer is washing water, the surface of the washing water is organic matter and other impurities, the organic matter on the surface of the upper layer is scraped off, and then the upper washing water is collected for recycling; collect the bottom phosphogypsum, filter press dehydration (water content is less than 5%), add quicklime and polyaluminium chloride, mix well, store and age for 20 days, and obtain harmless fresh phosphogypsum; the amount of quicklime and polyaluminium chloride (PAC) added is 3% and 0.5‰ of the mass of the phosphogypsum after filter press dehydration, respectively; S2: crush the phosphogypsum in the stockpile (phosphogypsum stored outdoors for more than 3 months) into a powder with a particle size not exceeding 10 μm, then mix the obtained phosphogypsum powder in the stockpile with quicklime, polyaluminium chloride and ammonium dithiocarbamate (heavy metal chelating agent) in a mass ratio of 100:4:0.1:0.3, and then store and age the mixture for 60 days to obtain harmless stockpile phosphogypsum; S3: crushing the phosphate tailings with a phosphorus pentoxide content of less than 5% into particles with a particle size of about 50 μm to obtain aggregate; S4: uniformly mixing harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cement in a mass ratio of 45:45:5:5 to obtain a mixture; S5: Load the mixture into a mold (240mm×115mm×53mm), press at a pressure of 40MPa for 20min, then demold and cure outdoors for 10 days.

[0022] Example 2 A mine repair material is prepared by the following steps: S1: Mix fresh phosphogypsum and water at a material-liquid ratio of 1kg:3L, add sodium dodecylbenzene sulfonate as a flotation agent to the mixture, and the amount of sodium dodecylbenzene sulfonate added is 0.01‰ of the mass of the fresh phosphogypsum; then stir at a stirring rate of 60rpm, and blow air in during the stirring process for 8 minutes, then let it stand for 15 minutes, the phosphogypsum precipitates to the lower layer, the upper layer is washing water, the surface of the washing water is organic matter and other impurities, the organic matter on the surface of the upper layer is scraped off, and then the upper washing water is collected for recycling; collect the bottom phosphogypsum, filter press dehydration (water content is less than 5%), add quicklime and polyaluminium chloride, mix well, store and age for 15 days, and obtain harmless fresh phosphogypsum; the amount of quicklime and polyaluminium chloride (PAC) added is 1% and 1‰ of the mass of the phosphogypsum after filter press dehydration, respectively; S2: crush the phosphogypsum in the stockpile (phosphogypsum stored outdoors for more than 3 months) into a powder with a particle size not exceeding 10 μm, then mix the obtained phosphogypsum powder in the stockpile with quicklime, polyaluminium chloride and ammonium dithiocarbamate (heavy metal chelating agent) in a mass ratio of 100:3:0.1:0.5, and then store and age the mixture for 30 days to obtain harmless stockpile phosphogypsum; S3: crushing the phosphate tailings with a phosphorus pentoxide content of less than 5% into particles with a particle size of about 20 μm to obtain aggregate; S4: uniformly mixing harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and building gypsum powder in a mass ratio of 45:45:5:5 to obtain a mixture; S5: Load the mixture into a mold (240mm×115mm×53mm), press at a pressure of 40MPa for 20min, then demold and cure outdoors for 10 days.

[0023] Example 3 A mine repair material is prepared by the following steps: S1: Mix fresh phosphogypsum and water at a solid-liquid ratio of 1kg:5L, then stir at a stirring rate of 60rpm, and introduce air during the stirring process for 15min, then let it stand for 5min, the phosphogypsum settles to the lower layer, the upper layer is washing water, the surface of the washing water is organic matter and other impurities, the organic matter on the surface of the upper layer is scraped off, and then the upper washing water is collected for recycling; collect the bottom phosphogypsum, filter press dehydration (water content is less than 5%), add quicklime, mix well, store and age for 30 days, and obtain harmless fresh phosphogypsum; the amount of quicklime added is 5% of the mass of the phosphogypsum after filter press dehydration; S2: crush the phosphogypsum in the stockpile (phosphogypsum stored outdoors for more than 3 months) into a powder with a particle size not exceeding 10 μm, then mix the obtained phosphogypsum powder in the stockpile with quicklime, polyaluminium chloride and ammonium dithiocarbamate (heavy metal chelating agent) in a mass ratio of 100:5:0.1:0.1, and then store and age the mixture for 90 days to obtain harmless stockpile phosphogypsum; S3: crushing the phosphate tailings with a phosphorus pentoxide content of less than 5% into particles with a particle size of about 100 μm to obtain aggregate; S4: uniformly mixing harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cement in a mass ratio of 45:45:5:5 to obtain a mixture; S5: Load the mixture into a mold (240mm×115mm×53mm), press at a pressure of 40MPa for 20min, then demold and cure outdoors for 10 days.

[0024] Example 4 A mine repair material, whose preparation process is compared with that of Example 1, wherein the mass ratio of harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cement in S4 is adjusted to 90:0:5:5, and the other conditions are the same as those of Example 1.

[0025] Example 5 A mine repair material, whose preparation process is compared with that of Example 1, wherein the mass ratio of harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cement in S4 is adjusted to 0:90:5:5, and the other conditions are the same as those of Example 1.

[0026] Example 6 A mine repair material, whose preparation process is compared with that of Example 1, wherein the mass ratio of harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cement in S4 is adjusted to 45:45:10:0, and the other conditions are the same as those of Example 1.

[0027] Example 7 A mine repair material, whose preparation process is compared with that of Example 1, wherein the mass ratio of harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cement in S4 is adjusted to 50:45:0:5, and the other conditions are the same as those of Example 1.

[0028] Example 8 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing time in S5 is adjusted to 0.5 min, and the other conditions are the same as those of Example 1.

[0029] Example 9 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing time in S5 is adjusted to 1 min, and the other conditions are the same as those of Example 1.

[0030] Example 10 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing time in S5 is adjusted to 2 minutes, and the other conditions are the same as those of Example 1.

[0031] Embodiment 11 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing time in S5 is adjusted to 5 minutes, and the other conditions are the same as those of Example 1.

[0032] Example 12 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing time in S5 is adjusted to 10 minutes, and the other conditions are the same as those of Example 1.

[0033] Example 13 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 30 MPa, the pressing time is adjusted to 0.5 min, and the other conditions are the same as those of Example 1.

[0034] Embodiment 14 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 30 MPa, the pressing time is adjusted to 1 min, and the other conditions are the same as those of Example 1.

[0035] Embodiment 15 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 30 MPa, the pressing time is adjusted to 2 min, and the other conditions are the same as those of Example 1.

[0036] Example 16 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 30 MPa, the pressing time is adjusted to 5 min, and the other conditions are the same as those of Example 1.

[0037] Embodiment 17 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 30 MPa, the pressing time is adjusted to 10 min, and the other conditions are the same as those of Example 1.

[0038] Embodiment 18 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 30 MPa, and the other conditions are the same as those of Example 1.

[0039] Comparative Example 1 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 10 MPa, the pressing time is adjusted to 0.5 min, and the other conditions are the same as those of Example 1.

[0040] Comparative Example 2 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 10 MPa, the pressing time is adjusted to 1 min, and the other conditions are the same as those of Example 1.

[0041] Comparative Example 3 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 10 MPa, the pressing time is adjusted to 2 min, and the other conditions are the same as those of Example 1.

[0042] Comparative Example 4 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 10 MPa, the pressing time is adjusted to 5 min, and the other conditions are the same as those of Example 1.

[0043] Comparative Example 5 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 10 MPa, the pressing time is adjusted to 10 min, and the other conditions are the same as those of Example 1.

[0044] Comparative Example 6 A mine repair material, whose preparation process is compared with that of Example 1, wherein the pressing pressure in S5 is adjusted to 10 MPa, and the other conditions are the same as those of Example 1.

[0045] Comparative Example 7 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 20 MPa, the pressing time is adjusted to 0.5 min, and the other conditions are the same as those of Example 1.

[0046] Comparative Example 8 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 20 MPa, the pressing time is adjusted to 1 min, and the other conditions are the same as those of Example 1.

[0047] Comparative Example 9 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 20 MPa, the pressing time is adjusted to 2 min, and the other conditions are the same as those of Example 1.

[0048] Comparative Example 10 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 20 MPa, the pressing time is adjusted to 5 min, and the other conditions are the same as those of Example 1.

[0049] Comparative Example 11 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 20 MPa, the pressing time is adjusted to 10 min, and the other conditions are the same as those of Example 1.

[0050] Comparative Example 12 A mine repair material, whose preparation process is compared with that of Example 1, in which the pressing pressure in S5 is adjusted to 20 MPa, and the other conditions are the same as those of Example 1.

[0051] Results Analysis The fluoride, total phosphorus and sulfate contents and pH values ​​of the fresh phosphogypsum, stockpile phosphogypsum and phosphate tailings used as raw materials in the present invention, as well as the harmless fresh phosphogypsum and harmless stockpiled phosphogypsum prepared in Examples 1 to 3 were tested by HJ 557 leaching method, and the free water content of the mine repair material was determined with reference to GB / T 23451-2009. The results are shown in Table 1.

[0052] Table 1 Characteristic pollutant content of raw materials and intermediate products

[0053] It can be seen from Table 1 that after treatment by the method of the present invention, the content of characteristic pollutants in fresh phosphogypsum and stockpile phosphogypsum decreased significantly, and the harmless fresh phosphogypsum and harmless stockpiled phosphogypsum obtained after treatment met the requirements of Class I general industrial solid waste in GB18599-2020 (fluoride ≤10 mg / L, phosphorus ≤0.5 mg / L, free water content ≤12%, pH 6~9).

[0054] The HJ 557 leaching method was also used to test the fluoride, total phosphorus and sulfate contents and pH values ​​of the mine repair materials obtained in the above Examples 1 to 7 (the compositions of the mine repair materials in Examples 8 to 18 and Comparative Examples 1 to 12 are the same as in Example 1, and only the mechanical properties are different, so their characteristic pollutant contents are basically the same as in Example 1). The free water content of the mine repair materials was determined with reference to GB / T23451-2009, and the results are shown in Table 2.

[0055] Table 2 Characteristics of mine repair materials

[0056] The mechanical properties of the mine repair materials prepared in the above embodiments and comparative examples were tested using the test standards in "Lightweight partition boards for construction" (GB / T 23451-2009) and "Non-load-bearing hollow concrete bricks" (GB / T 24492-2009). The results are shown in Table 3.

[0057] Table 3 Mechanical properties of mine repair materials

[0058] Experimental example The mine pit repair material prepared in Example 1 is used to repair the mine pit, which specifically includes the following steps: 1. Bottom and slope cleaning 1. Clean up the accumulated water, debris and weeds at the bottom of the mine to keep the bottom clean and flat; clear the dangerous rocks on the slopes of the mine.

[0059] 2. Bottom and slope reinforcement: According to safety requirements, reinforce damaged, cracked or unstable areas.

[0060] 3. Bottom anti-seepage and surrounding flood and anti-seepage: repair and anti-seepage treatment of cracks on the bottom and the vertical surface of the mine, and carry out flood prevention reinforcement around the mine.

[0061] 4. Retaining wall and internal partition frame structure: Use mine repair materials to build a retaining wall on the drainage side of the mine, divide the interior, and cast partition walls with concrete to divide the interior of the mine to facilitate subsequent zoning construction; and the retaining wall and partition wall play a role in supporting the subsequent backfill of hard blocks.

[0062] 5. Leachate collection system: A leachate collection and drainage ditch should be laid at the bottom of the mine pit, passing through the bottom of the retaining wall and entering the leachate collection pool. The mine leachate caused by subsequent construction or rainfall will be effectively collected in the leachate pool. The leachate must be tested and qualified to meet the surface water quality standards before it can be discharged.

[0063] 2. Backfill 1. Backfill in different areas and layers (building block style, interlocking steps), compact and fill the gaps with cementitious materials, and compact appropriately to reduce settlement and deformation.

[0064] 2. Waterproofing and drainage measures: Waterproofing measures prevent the entry of rainwater and groundwater; drainage measures such as pipes are set up inside the backfill body to remove the accumulated water in the backfill body.

[0065] 3. Inspection and evaluation: During and after the backfilling process, monitor and evaluate the stability, deformation and surrounding environment of the backfill body to promptly identify and address possible problems.

[0066] 3. Top seepage prevention, soil leveling and ecological restoration 1. Pour 10~15cm of impermeable concrete (P8 grade) on the top to form an almost impermeable protective layer.

[0067] 2. Cover the impermeable layer with a certain thickness of cultivated soil (25~45cm), carry out reclamation and greening, and complete the rigid backfill ecological restoration of the mine pit with phosphogypsum as the main repair material.

[0068] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A method for preparing a mine repair material, characterized in that: The following steps are involved: S1: Mix fresh phosphogypsum with water at a material-liquid ratio of 1kg:3~5L, add a flotation agent to the mixture, then stir and aerate for 8~15min, then let it stand for 5~15min, remove the upper water layer, collect the bottom phosphogypsum, add quicklime and polyaluminium chloride after dehydration by filter pressing, mix well and store for aging for 15~30 days to obtain harmless fresh phosphogypsum; S2: crushing the phosphogypsum in the stockpile into powder with a particle size not exceeding 10 μm, then mixing the obtained phosphogypsum powder in the stockpile with quicklime, polyaluminium chloride and a heavy metal chelating agent, and then stockpiling and aging the mixture for 30 to 90 days to obtain harmless stockpiled phosphogypsum; S3: crushing the phosphate tailings with a phosphorus pentoxide content of less than 5% into particles with a particle size of 20-100 μm to obtain aggregate; S4: uniformly mixing harmless fresh phosphogypsum, harmless stockpiled phosphogypsum, aggregate and cementitious material in a mass ratio of 0-90:0-90:0-10:0-5 to obtain a mixture; the cementitious material is cement or building gypsum powder; S5: Put the mixture into the mold, press it at a pressure of 30-40MPa for 0.5-20min, then demold it and cure it outdoors for 2-15 days.

2. The preparation method according to claim 1, characterized in that: The added amount of the flotation agent is 0-0.01‰ of the mass of fresh phosphogypsum; the flotation agent is sodium dodecylbenzene sulfonate.

3. The preparation method according to claim 1, characterized in that: The amounts of quicklime and polyaluminium chloride added in S1 are 1-5% and 0-1‰ of the mass of phosphogypsum after filter pressing and dehydration, respectively.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the phosphogypsum powder, quicklime, polyaluminium chloride and heavy metal chelating agent in the stockpile is 100:3-5:0.1:0.1-0.

5.

5. The preparation method according to claim 1 or 4, characterized in that: The heavy metal chelating agent is dithiocarbamate.

6. The preparation method according to claim 3, characterized in that: The stockpiling aging time in S2 is 60 days.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the harmless fresh phosphogypsum, the harmless stockpiled phosphogypsum, the aggregate and the cementitious material is 45:45:5:

5.

8. The preparation method according to claim 7, characterized in that: In S5, the pressing pressure is 40 MPa and the pressing time is 20 min; the curing time is 10 days.

9. A mine repair material, characterized in that: The method is prepared by the preparation method according to any one of claims 1 to 8.

10. The use of the mine repair material according to claim 9, characterized in that: The pit repair materials are used in mine pit repair.

Images