Method for increasing specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass

Abstract

The application provides a method for improving the specific surface area of red mud by using food fermentation waste liquid and agricultural and forestry biomass, and the specific steps are as follows: first, the red mud is dried, crushed, ground and sieved, then the acidic fermentation waste liquid is added to the mixture of the red mud and the agricultural and forestry biomass to perform red mud dealkalization and biomass humus fermentation treatment, and then the mixed filter residue is obtained by filtration, and the low-salt and low-alkali red mud with high specific surface area is obtained after high-temperature calcination of the mixed filter residue; the method can effectively improve the specific surface area of the red mud, reduce the alkalinity and salinity of the red mud, and improve the adsorption capacity of the red mud, and has application prospects in the fields of sewage treatment, heavy metal adsorption, soil improvement and the like, solves the problem of large storage of the red mud, and also enables the fermentation waste liquid of a brewing enterprise and the agricultural biomass to be environmentally treated, turns waste into treasure, and improves the value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of functional inorganic materials and solid waste resource utilization, in particular to a method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass. BACKGROUND

[0002] Red mud is an industrial solid waste discharged in the extraction of alumina in the aluminum industry. Due to the strong alkalinity, fine particle size and complex composition of red mud, its large-scale comprehensive utilization is difficult.

[0003] Food fermentation waste liquid is a liquid waste produced by brewing-type food production enterprises during food brewing. Under the action of microorganisms, it produces a liquid waste rich in organic acids, amino acids and other substances, and has high COD, high BOD, high biological activity, high color, acidity, low dissolved oxygen, high nitrogen concentration, high phosphorus concentration and other physicochemical properties. The treatment cost of such waste liquid is extremely high, and direct discharge will cause serious pollution to water environment, affect ecological environment and lead to decline of aquatic biodiversity. In addition, the large amount of inorganic salts in fermentation waste liquid will cause soil salinization, affect the ecological environment of soil and have adverse effects on crop growth. Volatile organic compounds and odor substances in fermentation waste liquid will affect air quality and bring inconvenience to the surrounding environment and residents' life.

[0004] Red mud contains a large amount of useful components and is an ideal building material, adsorbent and soil improvement raw material. However, the high alkalinity of red mud limits its application range. When used as an adsorbent, the specific surface area of red mud should be increased to ensure its adsorption effect. The specific surface area of untreated red mud is only about 10 m 2 / g, and the composition is complex. If it is applied as an adsorbent, increasing its specific surface area is the key to its large-scale application. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the defects of the prior art and provide a method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass. The method uses red mud, food fermentation waste liquid and agricultural and forestry biomass as raw materials, neutralizes and removes the alkaline substances in the red mud through fermentation treatment, and then dissolves some calcium salts, iron salts and other substances. After filtration and high-temperature calcination of the fermentation residue, a modified red mud with a specific surface area 5-20 times larger than that of the original red mud is obtained, which can effectively solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides a method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass, comprising the following steps:

[0007] S1) Pretreatment of red mud: drying, crushing, grinding and sieving the red mud.

[0008] S2) Pretreatment of agroforestry biomass: the agroforestry biomass is crushed into small particles of 1-5 mm.

[0009] S3) The S1 and S2 are mixed uniformly, a certain amount of food fermentation acidic waste liquid is added, stirred uniformly, reacted at a certain temperature for 7-28 days, and then filtered to obtain filter residue.

[0010] S4) The filter residue obtained in S3 is subjected to high-temperature calcination treatment to obtain low-salt and low-alkali red mud with high specific surface area.

[0011] As a preferred technical solution of the present application: the red mud is a high-alkali waste residue produced by the Bayer process, sintering process or combined process of an alumina plant.

[0012] As a preferred technical solution of the present application: the drying temperature in S1 is 65-110°C.

[0013] As a preferred technical solution of the present application: the sieving in S1 is 60 mesh.

[0014] As a preferred technical solution of the present application: the biomass in S2 is one or more of straw, bark, leaves, branches, sawdust, bagasse, fruit peel, etc.

[0015] As a preferred technical solution of the present application: the mass ratio of red mud to agroforestry biomass in S3 is 10:1-10:10.

[0016] As a preferred technical solution of the present application: the mass ratio of agroforestry biomass mixture to fermentation waste liquid in S3 is 10:3-10:10.

[0017] As a preferred technical solution of the present application: the fermentation temperature in S3 is 20-50°C.

[0018] As a preferred technical solution of the present application: the calcination temperature in S4 is 200-1000°C.

[0019] Compared with the prior art, the present application has the beneficial effects that: the acid substance and the microbial metabolite jointly act on the alkali substance of the red mud to perform a dealkalization reaction, the agroforestry biomass is subjected to humic fermentation treatment, and after mixing and calcination, the specific surface area of the modified red mud reaches 50-200 m 2 / g, at the same time, the acidity of the fermentation waste liquid is neutralized, the biological activity is inhibited, and the biomass is humified. This not only greatly improves the resource utilization efficiency of the red mud, but also can treat the acidic fermentation waste liquid of the food industry, achieving the purpose of waste treatment with waste. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The figure is a test result diagram of Example 1 of the present application.

[0021] Figure 2 The test result diagram of the embodiment two of the present application.

[0022] Figure 3 The test result diagram of the embodiment three of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0024] The present application provides the following technical solutions:

[0025] The red mud is dried at 80℃, and after cooling, it is ground by a grinding machine, and then is passed through a 60-mesh sieve for storage; the food fermentation acidic waste liquid is filtered and stored for later use; the biomass is crushed into small particles of 1-5mm for storage.

[0026] Embodiment one:

[0027] 10 parts of red mud, 1 part of straw, 1 part of sawdust, 1 part of leaves and 10 parts of white wine fermentation waste liquid are placed in a reaction container, and after being stirred uniformly, they are reacted at room temperature for 20 days. After the reaction is completed, the solid is filtered, and the obtained filter residue is dried and then is placed in a muffle furnace for calcination at 600℃ for 2h. After being cooled to room temperature, the sample is crushed, ground and passed through a 60-mesh sieve to obtain a high specific surface area low-salt low-alkali red mud with a specific surface area of 53.46m 2 / g, a pore volume of 0.0077cm 3 / g and a pH value of 8.34. The test results are shown in the figure.

[0028] Embodiment two:

[0029] 10 parts of red mud, 2 parts of straw, 1 part of bagasse, 1 part of fruit peel and 5 parts of white wine fermentation waste liquid are placed in a reaction container, and after being stirred uniformly, they are reacted at room temperature for 28 days. After the reaction is completed, the solid is filtered, and the obtained filter residue is dried and then is placed in a muffle furnace for calcination at 700℃ for 2h. After being cooled to room temperature, the sample is crushed, ground and passed through a 60-mesh sieve to obtain a high specific surface area low-salt low-alkali red mud with a specific surface area of 73.16m 2 / g, a pore volume of 0.0262cm 3 / g and a pH value of 7.76. The test results are shown in the figure.

[0030] Embodiment three:

[0031] 10 parts of red mud, 3 parts of bagasse, 2 parts of tree bark, 1 part of tree branches and 10 parts of fermentation waste liquid of salt-free Chinese cabbage were placed in a reaction container, stirred uniformly and reacted at room temperature for 20 days. After the reaction was completed, the solid was filtered, the obtained filter residue was dried, placed in a muffle furnace and calcined at 500°C for 2h, the sample was crushed, ground and passed through a 60 mesh sieve after cooling to room temperature, to obtain a high specific surface area low-salt low-alkali red mud with a specific surface area of 160.68m 2 / g, a pore volume of 0.0207cm 3 / g and a pH value of 7.20, and the test results are shown in the figure.

[0032] Example Four:

[0033] 10 parts of red mud, 8 parts of straw and 10 parts of beer fermentation waste liquid were placed in a reaction container, stirred uniformly and reacted at room temperature for 20 days. After the reaction was completed, the solid was filtered, the obtained filter residue was dried, placed in a muffle furnace and calcined at 700°C for 2h, the sample was crushed, ground and passed through a 60 mesh sieve after cooling to room temperature, to obtain a high specific surface area low-salt low-alkali red mud with a specific surface area of 135.34m 2 / g, a pore volume of 0.0146cm 3 / g and a pH value of 7.13, and the test results are shown in the following table.

[0034] Isotherm Tabular Report

[0035]

[0036] Table 1 Change of main element content of red mud before and after modification (% by mass)

[0037]

[0038] Table 2 Change of specific surface area and pore volume of red mud before and after modification

[0039]

[0040] The present application uses red mud, fermentation waste liquid and agricultural and forestry biomass as raw materials, adds acidic fermentation waste liquid to the mixture of red mud and agricultural and forestry biomass, makes the red mud dealkalization and the biomass humic fermentation, and after filtration and calcination, a high specific surface area low-salt low-alkali red mud is obtained. Strengthening the resource utilization of red mud can reduce the pollution of red mud to the ecological environment, increase the comprehensive utilization rate of red mud, and also neutralize the acidity in the fermentation waste liquid, making it possible for red mud to replace activated carbon as a water purifying agent.

[0041] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary and that changes can be made in detail without departing from the principles and spirit of the application. The scope of the application is therefore indicated by the appended claims, along with equivalents thereof.

Claims

1. A method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agroforestry biomass, characterized by: The method comprises the following steps: S1) Pretreatment of red mud: drying, crushing, grinding and sieving the red mud; The red mud is a high-alkaline waste residue generated by an alumina plant using the Bayer process, sintering process or combined process; S2) Pretreatment of agricultural and forestry biomass: crushing the agricultural and forestry biomass into small particles of 1-5 mm; the agricultural and forestry biomass is one or several of straw, bark, leaves, branches, sawdust, bagasse and fruit peel; S3) uniformly mixing S1 and S2, adding a certain amount of food fermentation acidic waste liquid, uniformly stirring, reacting at a certain temperature for 20-28 days, and then filtering to obtain filter residue; the food fermentation acidic waste liquid is liquor fermentation waste liquid or salt-free pickled vegetable fermentation waste liquid or beer fermentation waste liquid; S4) high-temperature calcination treatment of the filter residue obtained in S3 to obtain low-salt and low-alkali red mud with high specific surface area; the calcination temperature in S4 is 200-1000°C.

2. The method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass according to claim 1, characterized in that: The drying temperature in S1 is 65-110°C.

3. The method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass according to claim 1, characterized in that: The sieving in S1 is 60-mesh sieving.

4. The method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass according to claim 1, characterized in that: The mass ratio of red mud to agricultural and forestry biomass in S3 is 10:1-10:

10.

5. The method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agricultural and forestry biomass according to claim 1, characterized in that: The mass ratio of the agricultural and forestry biomass mixture to the fermentation waste liquid in S3 is 10:3-10:

10.

6. The method for increasing the specific surface area of red mud by using food fermentation waste liquid combined with agroforestry biomass according to claim 1, characterized in that: The reaction temperature in S3 is 20-50°C.

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