System for treating low-temperature Bayer process red mud

Abstract

The utility model provides a system for treating low-temperature Bayer process red mud, and relates to the field of solid waste recycling. Comprising Bayer process low-temperature red mud, a composite additive, a weighing device and a dissolver, the dissolver is communicated with a dilution tank, the dilution tank is communicated with a filter unit, the filter unit is respectively communicated with a multi-stage washing device and a seed crystal decomposition tank, the multi-stage washing device is communicated with a drying device, and the drying device is communicated with a first warehouse; the seed crystal decomposition tank is communicated with a filter, the filter is respectively communicated with an evaporation concentration device and a roasting furnace, the roasting furnace is communicated with a second warehouse, and the evaporation concentration device is communicated with a dissolver; according to the utility model, the iron-calcium composite additive is adopted as a main reaction auxiliary agent and is subjected to accurate proportioning and directional reaction with the high-iron guineite bauxite, aluminum and sodium which are lost in secondary reaction and enter the red mud are separated and recovered in the dissolution process, and the red mud is converted into an iron ore concentrate powder product in the production process, so that the efficient separation and utilization of aluminum and iron are realized; the method is energy-saving, environment-friendly, low in cost and remarkable in economic benefit and environmental benefit.

Description

TECHNICAL FIELD

[0001] The utility model relates to solid waste resource technology field, especially point to a system for treating low temperature bayer process red mud. BACKGROUND

[0002] The bauxite in Guinea has the characteristics of high aluminum (Al2O3 content usually more than 45%), high iron (Fe2O3 content about 20-30%) and low silicon (SiO2 content about 1-2.5%).

[0003] At present, in the process of treating high-iron Guinea bauxite by bayer method, Al2O3 is extracted as valuable resources, and a large amount of Fe2O3 is discarded in red mud and cannot be effectively utilized, which not only pollutes the environment and occupies land, but also is a great waste of valuable iron resources. If the iron-containing substances in high-iron Guinea bauxite can be efficiently utilized, not only can the harm caused by red mud storage be reduced, but also the import cost of iron ore and its concentrate can be greatly reduced, realizing the aluminum and iron step-by-step extraction and utilization of high-iron bauxite.

[0004] The red mud discharged in the production of alumina by low-temperature bayer method contains metal oxides such as iron oxide and aluminum oxide. The existing technology for recovering iron and aluminum from red mud mainly has the following disadvantages: the content of iron-containing components in red mud is required, the obtained iron concentrate needs to be subjected to an iron selection process to obtain iron concentrate; strong magnetic separation is required, the recovery efficiency of iron and aluminum is low, the environment is polluted, the energy consumption is high, it is not environmentally friendly; the implementation difficulty is large, the energy utilization rate is low, the cost is high, and the process is complex.

[0005] The traditional red mud aluminum and iron recovery method has the following disadvantages: ① carbon thermal reduction method for treating red mud, additional disposal process is required for the discharged red mud, and a large amount of carbon dioxide is generated in the process; ② direct strong magnetic separation treatment cannot effectively separate a large amount of non-magnetic hematite in red mud; ③ alkali treatment of red mud further increases the alkali content in red mud, making subsequent resource utilization more difficult. UTILITY MODEL CONTENT

[0006] In order to solve the technical problems existing in the prior art, the embodiments of the utility model provide a system for treating low-temperature bayer process red mud. The technical scheme is as follows:

[0007] The system for processing low-temperature Bayer process red mud comprises a Bayer process low-temperature red mud, a composite additive, a weighing device and a leaching device, the leaching device is connected with a dilution tank, the dilution tank is connected with a filtration unit, the filtration unit is connected with a multi-stage washing device and a seed crystal decomposition tank respectively, the multi-stage washing device is connected with a drying device, the drying device is connected with a first storage, the seed crystal decomposition tank is connected with a filter, the filter is connected with an evaporation and concentration device and a calcination furnace respectively, the calcination furnace is connected with a second storage, and the evaporation and concentration device is connected with the leaching device.

[0008] Optionally, the mixture of the Bayer process low-temperature red mud and the composite additive is weighed by the weighing device and then enters the leaching device for reaction, and steam and alkali liquor are introduced into the leaching device.

[0009] Optionally, the components of the composite additive are one or more of calcium oxide, calcium hydroxide, calcium ferrite, calcium silicate and fayalite.

[0010] Optionally, when the mixture is introduced into the leaching device for reaction, the reaction temperature is 250 DEG C to 270 DEG C, and the reaction time in the leaching device is 10 min to 120 min.

[0011] Optionally, the concentration of the alkali liquor is 20 g / L to 200 g / L, and the solid-liquid ratio in the leaching device is 100 g / L to 400 g / L.

[0012] Optionally, the molar ratio of calcium to silicon in the composite additive is between 1 and 3, and the molar ratio of iron to silicon in the composite additive is between 0.5 and 2.

[0013] The technical scheme provided by the embodiment of the utility model has at least the following beneficial effects:

[0014] The technical scheme of the utility model provides a composite additive processing method, aiming at efficiently extracting iron and aluminum resources in red mud respectively, preparing aluminum oxide and iron concentrate, and realizing the resource utilization of waste materials. The utility model not only helps to improve the resource utilization efficiency of the metallurgical industry, but also effectively reduces the negative impact of waste materials on the environment and promotes the process of green and sustainable development. The technical scheme of the utility model is economical, has little environmental pollution, and does not produce secondary solid waste.

[0015] The utility model can realize the source modification of red mud, does not need to perform additional treatment on the red mud, directly prepares iron concentrate powder, adds a composite additive in the leaching process, can replace and extract aluminum and sodium in the red mud which is lost in the secondary reaction, reduces the content of aluminum and sodium in the red mud, realizes energy saving and consumption reduction in the production process and the reduction and value-added utilization of red mud. The scheme utilizes an alkaline wet process, has low energy consumption, and realizes the recycling of alkali liquor, solves the problem of high energy consumption in the fire roasting process, and solves the problem of wastewater pollution in the acidic system leaching process.

[0016] The scheme adopts iron-calcium composite additives as main reaction aids, and through precise proportioning and directional reaction with high-iron Guinea bauxite, aluminum and sodium in the red mud due to secondary reaction loss are separated and recovered in the dissolution process, the red mud is converted into iron concentrate powder product in the production process, the aluminum and iron components in the low-temperature red mud can be separated and high-value utilized; the alumina dissolution rate of the high-iron bauxite is significantly improved, and the alkali consumption in production is reduced; both the phase inversion of the aluminum component can be realized so that it can be dissolved in the alkali liquor, and the grade of the iron concentrate can be improved so that it directly meets the product requirements without iron selection and tailing discharge; the reaction process of the scheme is easy to be combined with the existing bayer process for producing alumina, the alkali liquor is recycled, and no wastewater is discharged; the scheme has low cost, high product value, high resource utilization rate, no environmental pollution, realizes the aluminum and iron gradient extraction and utilization of Guinea bauxite "one mine two uses", and has remarkable economic and environmental benefits. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor on the premise of the drawings.

[0018] Figure 1 A schematic diagram of a system for treating low-temperature bayer process red mud is provided.

[0019] Reference signs:

[0020] 1, bayer process low-temperature red mud; 2, composite additive; 3, steam; 4, alkali liquor; 51, first solid material; 52, first filtrate; 61, second solid material; 62, second filtrate;

[0021] ①, weighing device; ②, dissolver; ③, dilution tank; ④, filtration unit; ⑤, crystal seed decomposition tank; ⑥, filter; ⑦, calcination furnace; ⑧, second storage; ⑨, evaporation and concentration device; ⑩, multi-stage washing device; , drying device; , first storage. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of the present application.

[0023] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the usual meaning understood by a person with ordinary skill in the art to which the present application belongs. The terms "first", "second" and similar words used in the present application do not represent any order, number or importance, but are only used to distinguish different components. Similarly, the terms "one", "an" or "the" and similar words do not represent a quantity limitation, but represent the existence of at least one. The terms "include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0024] It should be noted that "up", "down", "left", "right", "front", "back" and the like used in the present application are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationships may also change accordingly.

[0025] As shown in Figure 1 The present embodiment provides a system for treating low-temperature Bayer process red mud; comprising a Bayer process low-temperature red mud 1, a composite additive 2, a weighing device ①, a leaching device ② and a dilution tank ③, the leaching device ② is connected to the dilution tank ③, the leaching device ② is a high-temperature and alkali-resistant container, the dilution tank ③ is connected to a filtration unit ④, the filtration unit ④ is a device for separating solid and liquid, which is not described here as prior art, the filtration unit ④ is connected to a multi-stage washing device ⑩ and a crystal seed decomposition tank ⑤, the multi-stage washing device ⑩ is connected to a drying device , the multi-stage washing device ⑩ and the drying device are devices that can realize washing and drying functions, respectively, which are not described here as prior art, the drying device is connected to a first storage , the first storage The filter 6 is used to realize solid-liquid separation, which is prior art and will not be described here. The filter 6 is connected with the roasting furnace 7 and the evaporation and concentration device 9 respectively. The roasting furnace 7 is connected with the second storage 8, which is used to store and place alumina. The evaporation and concentration device 9 is connected with the leaching device 2.

[0026] The Bayer process low-temperature red mud 1 is mixed with a composite additive 2 to obtain a mixture. The composite additive 2 contains one or more of calcium oxide, calcium hydroxide, calcium ferrite, calcium silicate, and fayalite. The mixture is weighed in a weighing device 1, and then placed in a leaching device 2. High-temperature steam 3 and alkali 4 are introduced into the leaching device 2, and the mixture and the alkali 4 are subjected to a leaching reaction in the leaching device 2. The reaction product obtained after the leaching reaction is introduced into a dilution tank 3, which is diluted with water. The obtained slurry is subjected to solid-liquid separation in a filtration unit 4 to obtain a first solid material 51 and a first liquid material 52. The aluminum-containing components are in the first liquid material 52, and the iron-containing components are in the first solid material 51. Thus, the separation of aluminum and iron is achieved while realizing solid-liquid separation.

[0027] The first solid material 51 is washed in a multi-stage washing device 10, and the washed first solid material 51 is dried in a drying device to obtain iron concentrate. The obtained iron concentrate is stored in a first storage . Alkali is recovered during the washing process in the multi-stage washing device 10. The mass content of Fe2O3 in the iron concentrate is 70%-80%.

[0028] The first liquid material 52 is introduced into a seed decomposition tank 5, and a reaction is carried out by adding aluminum hydroxide seeds to precipitate aluminum hydroxide. The aluminum hydroxide is subjected to solid-liquid separation in a filter 6 to obtain a second solid material 61 and a second filtrate 62. The main component of the second solid material 61 is solid aluminum hydroxide.

[0029] The second solid material 61 is subjected to roasting in a roasting furnace 7 to obtain alumina, which is stored in a second storage 8. The second filtrate 62 is subjected to evaporation and concentration in an evaporation and concentration device 9, and the concentrated slurry is introduced into the leaching device 2 to undergo a leaching reaction with alkali 2 under high-temperature steam conditions to realize recycling.

[0030] The temperature during the leaching reaction in the leaching device 2 is 250°C-270°C, the leaching reaction time is 10 min-120 min, the concentration of the introduced alkali 4 is 20 g / L-200 g / L, and the solid-liquid ratio of the mixture of the Bayer process low-temperature red mud 1, the composite additive 2, and the alkali 4 in the leaching device 2 is 100 g / L-400 g / L. The amount of the composite additive 2 is determined according to the content of silicon, calcium, and iron in the composite additive 2. The molar ratio of calcium to silicon is 1-3, and the molar ratio of iron to silicon is 0.5-2.

[0031] The scheme proposes a composite additive treatment method, aiming at efficient extraction of iron and aluminum resources in red mud respectively, preparation of aluminum oxide and iron concentrate, and realization of waste resource utilization. The utility model not only helps to improve the resource utilization efficiency of metallurgical industry, but also effectively reduces the negative impact of waste on the environment, and promotes the process of green and sustainable development. The utility model technical scheme is economical, has little environmental pollution, and no secondary solid waste is produced.

[0032] The scheme can realize source modification of red mud, without additional treatment of red mud, directly preparing iron concentrate powder, adding composite additives in the dissolution process, replacing and extracting aluminum and sodium in red mud lost in secondary reaction, reducing the content of aluminum and sodium in red mud, realizing energy saving and consumption reduction in the production process and reduction and value-added utilization of red mud. The scheme uses alkaline wet process, has low energy consumption, and recycles alkali liquor, solving the problem of high energy consumption of fire roasting and the problem of wastewater pollution in acidic system leaching.

[0033] The scheme uses iron-calcium composite additive as the main reaction aid, and separates and recovers aluminum and sodium in red mud lost in secondary reaction through precise proportioning and directional reaction of high-iron Guinea bauxite, converts red mud into iron concentrate powder product in the production process, realizes separation and high-value utilization of aluminum and iron components in low-temperature red mud, significantly improves the alumina dissolution rate of high-iron bauxite, and reduces the alkali consumption in production. It can not only realize the phase inversion of aluminum components so that they can be dissolved in alkali liquor, but also improve the grade of iron concentrate so that it can directly meet the product requirements without iron selection and tailings discharge. The reaction process of the scheme is easy to combine with the existing Bayer process for producing alumina, and the alkali liquor is recycled without wastewater discharge. The scheme has low cost, high product value, high resource utilization rate, no environmental pollution, realizes the aluminum and iron gradient extraction and utilization of Guinea bauxite, and has significant economic and environmental benefits.

[0034] The following points need to be explained:

[0035] (1) The drawings of the embodiments of the utility model only involve the structures involved in the embodiments of the utility model, and other structures can be referred to the usual design.

[0036] (2) For the sake of clarity, the thickness of the layers or regions is exaggerated or reduced in the drawings used to describe the embodiments of the utility model, that is, these drawings are not drawn according to the actual proportion. It can be understood that when an element such as a layer, a film, a region or a substrate is referred to as being located "on" or "under" another element, the element can be "directly" located "on" or "under" another element or there can be an intermediate element.

[0037] (3) In the case of no conflict, the embodiments of the utility model and the features in the embodiments can be combined with each other to obtain new embodiments.

[0038] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A system for treating low temperature Bayer process red mud, characterised in that, The device comprises Bayer process low-temperature red mud, composite additive, weighing device and leaching device, the leaching device is connected with dilution tank, the dilution tank is connected with filtration unit, the filtration unit is connected with multi-stage washing device and crystal seed decomposition tank respectively, the multi-stage washing device is connected with drying device, the drying device is connected with first storage, the crystal seed decomposition tank is connected with filter, the filter is connected with evaporation and concentration device and calcining furnace respectively, the calcining furnace is connected with second storage, and the evaporation and concentration device is connected with the leaching device. Iron and aluminum resources in red mud are extracted and prepared into aluminum oxide and iron concentrate.

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