Red mud acid leaching waste residue modified curing agent and preparation method thereof

Abstract

The invention discloses a red mud acid leaching waste residue modified curing agent and a preparation method thereof, and belongs to the field of environmental protection engineering. The bauxite acid leaching waste residue modified curing agent is prepared from the following raw materials in parts by mass: 30 to 40 parts of magnesium sulfite, 30 to 35 parts of fly ash, 25 to 30 parts of alkaline residue, 1 to 5 parts of sodium sulfite, 1 to 5 parts of white carbon black and 0.5 part of polyaluminum ferric sulfate. Industrial solid waste and bauxite acid leaching waste residues are effectively utilized, and the curing agent has the advantages of being low in cost, simple in preparation method and high in resource utilization rate and is suitable for further application and popularization. According to the method, the pollution of the bauxite acid leaching waste residues can be effectively reduced, the long-term water stability of the bauxite acid leaching waste residue roadbed is improved, the requirement that the bauxite acid leaching waste residues are applied to road construction on a large scale is met, waste is turned into wealth, and non-renewable land resources are saved.

Description

Technical Field

[0001] The invention relates to the field of environmental protection engineering, and in particular to a red mud acid leaching waste residue modified curing agent and a preparation method thereof. Background Art

[0002] Bauxite acid leaching waste residue, also known as red mud, is a solid waste generated in the process of alumina production. Due to the differences in the main raw material bauxite, production process and other factors, the composition, properties and physical phase of bauxite acid leaching waste residue discharged by different types and different enterprises are different. Generally speaking, for every ton of alumina produced, 0.8 to 2.0 tons of bauxite acid leaching waste residue will be produced. How to treat and comprehensively utilize bauxite acid leaching waste residue has become the focus of social attention. At present, the process route for the comprehensive utilization of bauxite acid leaching waste residue is complex, with large investment, high energy consumption and high cost, and the utilization amount is small, which makes it difficult to apply it to industrial production and completely solve the environmental pollution problem of bauxite acid leaching waste residue.

[0003] With the rapid development of highway construction projects, road materials are consuming a large amount of non-renewable natural resources. If bauxite acid leaching waste can be used on a large scale in the construction of large-scale highway projects, it can not only turn waste into treasure and save precious non-renewable land resources, but also provide a most effective way for the large-scale reduction and application of industrial waste represented by bauxite acid leaching waste. The physical and mechanical properties, particle composition, chemical composition, etc. of bauxite acid leaching waste can meet the applicability requirements of road materials, and there are engineering practices for using it as roadbed filler and base material. The large-scale application of bauxite acid leaching waste in highway construction can not only turn waste into treasure, but also reduce the stockpile of bauxite acid leaching waste on a large scale. It is an effective way to achieve large-scale consumption and pollution-free discharge of bauxite acid leaching waste. Bauxite acid leaching waste usually needs to be modified by adding a curing agent when used as road material, but the existing traditional curing agent cannot effectively reduce the pollution of bauxite acid leaching waste, and the long-term water stability is poor, which seriously restricts the large-scale application of bauxite acid leaching waste in the highway industry.

[0004] Therefore, how to effectively reduce or eliminate the pollution of bauxite acid leaching waste, improve the long-term water stability of bauxite acid leaching waste roadbed, meet the performance conditions for large-scale application of bauxite acid leaching waste in highway construction, and save non-renewable land resources are technical problems that need to be solved urgently. Summary of the invention

[0005] The object of the present invention is to provide a red mud acid leaching waste residue modified curing agent and a preparation method thereof to solve the above-mentioned problems in the background technology. The present invention effectively utilizes industrial solid waste and bauxite acid leaching waste residue, and the curing agent of the present invention has the advantages of low cost, simple preparation method, and high resource utilization rate, and is suitable for further promotion and application. It can effectively reduce the pollution of bauxite acid leaching waste residue, improve the long-term water stability of bauxite acid leaching waste residue roadbed, meet the requirements of large-scale application of bauxite acid leaching waste residue in highway construction, turn waste into treasure, and save non-renewable land resources.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a bauxite acid leaching waste residue modified curing agent, the raw materials are calculated by weight and include:

[0008] 30-40 parts of magnesium sulfite, 30-35 parts of fly ash, 25-30 parts of alkali residue, 1-5 parts of sodium sulfite, 1-5 parts of white carbon black and 0.5 parts of polyaluminium ferric sulfate.

[0009] In the modified curing agent of the present invention, sodium sulfite and polyaluminium ferric sulfate act as reducing agents.

[0010] Preferably, the bauxite acid leaching waste residue modified curing agent is composed of the following raw materials in parts by mass:

[0011] 30-40 parts of magnesium sulfite, 30-35 parts of fly ash, 25-30 parts of alkali residue, 2-3 parts of sodium sulfite, 3-5 parts of white carbon black and 1-5 parts of polyaluminium ferric sulfate.

[0012] More preferably, the bauxite acid leaching waste slag modified curing agent is composed of the following raw materials in parts by mass:

[0013] 35 parts of magnesium sulfite, 30 parts of fly ash, 29 parts of alkali residue, 2.5 parts of sodium sulfite, 3 parts of white carbon black and 0.5 parts of polyaluminium ferric sulfate.

[0014] The second technical solution of the present invention is to provide a method for preparing the above-mentioned bauxite acid leaching waste residue modified curing agent, comprising the following steps:

[0015] The magnesium sulfite, fly ash and alkaline slag are crushed to obtain prefabricated powder, and then sodium sulfite, white carbon black and polyaluminium ferric sulfate are added and crushed again to obtain the bauxite acid leaching waste slag modified curing agent.

[0016] Preferably, the pulverizing is pulverizing until it passes through a 100-mesh sieve; and the secondary pulverizing is pulverizing until it passes through a 300-mesh sieve.

[0017] The third technical solution of the present invention is to provide an application of the above-mentioned bauxite acid leaching waste residue modification and curing agent in reducing the pollution of bauxite acid leaching waste residue.

[0018] The fourth technical solution of the present invention is to provide a bauxite acid leaching waste slag type roadbed material, wherein the bauxite acid leaching waste slag type roadbed material contains the above-mentioned bauxite acid leaching waste slag modified curing agent.

[0019] Preferably, the bauxite acid leaching waste slag modified curing agent accounts for 5-10wt% in the bauxite acid leaching waste slag type roadbed material.

[0020] The fifth technical solution of the present invention is to provide an application of the above-mentioned bauxite acid leaching waste slag type roadbed material in highway roadbed filling engineering.

[0021] Technical solution 6 of the present invention: Provide a method for using the above-mentioned bauxite acid leaching waste slag type roadbed material, comprising the following steps:

[0022] The bauxite acid leaching waste residue is mixed with the bauxite acid leaching waste residue modified curing agent, wetted, laid and cured.

[0023] The beneficial technical effects of the present invention are as follows:

[0024] The curing agent of the present invention adopts industrial waste materials such as magnesium sulfite, alkali residue, fly ash and the like as main raw materials, and is prepared by utilizing the complementary chemical properties between solid wastes. Calcium carbonate and calcium sulfate contained in the alkali residue, as well as calcium oxide, silicon oxide and aluminum oxide in the fly ash, can react with the bauxite acid leaching waste residue, thereby improving the particle size distribution, enhancing the overall strength and chemical stability of the roadbed material, and improving its durability by generating products such as aluminosilicate; magnesium sulfite can further supplement sulfate and sulfite, and combined with the excitation effect of calcium ions in the raw materials on the fly ash, it can promote the generation of hydrated calcium sulfoaluminate (AFt), thereby achieving the solidification of the bauxite acid leaching waste residue by stimulating the active substances, and providing convenience for the application of the bauxite acid leaching waste residue in the highway roadbed filling project.

[0025] The effective components in the curing agent of the present invention form insoluble substances with the heavy metal substances in the bauxite acid leaching waste residue, thereby achieving the purpose of reducing the pollution of the bauxite acid leaching waste residue and curing the heavy metal ions in the bauxite acid leaching waste residue; the regulator (sodium sulfite, polyaluminum ferric sulfate) and the stabilizer (white carbon black) in the curing agent work together to stimulate the active substances in the bauxite acid leaching waste residue, and the generated CSH and CASH gel can improve the strength of the bauxite acid leaching waste residue, so that the pollutants are wrapped and adsorbed and lose their migration characteristics; therefore, the curing agent of the present invention can be applied to the paving process of the bauxite acid leaching waste residue roadbed.

[0026] The present invention effectively utilizes industrial solid waste and bauxite acid leaching waste residue, and the curing agent of the present invention has the advantages of low cost, simple preparation method, and high resource utilization rate, and is suitable for further promotion and application. It can effectively reduce the pollution of bauxite acid leaching waste residue, improve the long-term water stability of bauxite acid leaching waste residue roadbed, meet the requirements of large-scale application of bauxite acid leaching waste residue in highway construction, turn waste into treasure, and save non-renewable land resources. DETAILED DESCRIPTION

[0027] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0028] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0029] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0031] The magnesium sulfite used in the following embodiments and comparative examples of the present invention is the magnesium sulfite obtained in the desulfurization process of the power plant; the fly ash is the low-sulfur fly ash with a sulfur content of less than 0.3%; and the alkali residue is the alkaline waste residue discharged during the alkali production and alkali treatment process in industrial production.

[0032] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0033] Example 1

[0034] The curing agent is composed of the following raw materials in parts by mass:

[0035] 35 parts of magnesium sulfite, 30 parts of fly ash, 29 parts of alkali residue, 2.5 parts of sodium sulfite, 3 parts of white carbon black and 0.5 parts of polyaluminium ferric sulfate.

[0036] Preparation of curing agent:

[0037] (1) Magnesium sulfite, fly ash and alkali residue are crushed, dried at 105° C., and crushed to pass through a 100-mesh sieve to obtain a prefabricated powder.

[0038] (2) Sodium sulfite, white carbon black and polyaluminium ferric sulfate are added to the above prefabricated powder, mixed thoroughly and evenly, and crushed for a second time until the powder passes through a 300-mesh sieve to obtain a curing agent (referred to as curing agent A).

[0039] Example 2

[0040] The only difference from Example 1 is that the proportions of the raw materials are adjusted to the form shown in Table 1 to obtain curing agent B, curing agent C, and curing agent D.

[0041] Table 1

[0042]

[0043] Example 3

[0044] The bauxite acid leaching waste slag type roadbed material was prepared according to the raw material ratio in Table 2, and the traditional roadbed paving material prepared with magnesium sulfite and slaked lime as a curing agent was used as a control group.

[0045] Table 2

[0046] Curing agent type Curing agent ratio (%) Acid leaching waste residue ratio of bauxite (%) Group 1 Curing agent B 6 94 Group 2 Curing Agent A 6 94 Group 3 Curing Agent C 6 94 Group 4 Curing agent D 6 94 Group 5 Magnesium sulfite 6 94 Group 6 Slaked lime 6 94

[0047] The above-mentioned bauxite acid leaching waste slag roadbed material is paved into a road surface by mixing the bauxite acid leaching waste slag with a curing agent, adding water according to an optimum water content, paving, and curing for 7 days. The optimum water content is determined by referring to the compaction test T0131-2007 of the Highway Geotechnical Test Code (JTG E40-2007).

[0048] Effect verification

[0049] (1) The unconfined compressive strength and heavy metal ion leaching concentration tests were performed on the samples of Example 3; the heavy metal ion leaching concentration test was performed in accordance with the Groundwater Quality Standard (GB / T 14848-9). The test results are shown in Tables 3 and 4.

[0050] Table 3

[0051]

[0052] Table 4

[0053]

[0054]

[0055] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A bauxite acid leaching waste residue modified curing agent, characterized in that: Raw materials, calculated by mass, include: 30-40 parts of magnesium sulfite, 30-35 parts of fly ash, 25-30 parts of alkali residue, 1-5 parts of sodium sulfite, 1-5 parts of white carbon black and 0.5 parts of polyaluminium ferric sulfate.

2. The bauxite acid leaching waste slag modified curing agent according to claim 1, characterized in that: The bauxite acid leaching waste residue modified curing agent is composed of the following raw materials in parts by mass: 35 parts of magnesium sulfite, 30 parts of fly ash, 29 parts of alkali residue, 2.5 parts of sodium sulfite, 3 parts of white carbon black and 0.5 parts of polyaluminium ferric sulfate.

3. A method for preparing the bauxite acid leaching waste slag modified curing agent according to claim 1 or 2, characterized in that: The following steps are involved: The magnesium sulfite, fly ash and alkaline slag are crushed to obtain prefabricated powder, and then sodium sulfite, white carbon black and polyaluminium ferric sulfate are added and crushed again to obtain the bauxite acid leaching waste slag modified curing agent.

4. The preparation method according to claim 3, characterized in that: The pulverizing is pulverizing until it passes through a 100-mesh sieve; and the secondary pulverizing is pulverizing until it passes through a 300-mesh sieve.

5. Use of the bauxite acid leaching waste residue modified curing agent according to claim 1 or 2 in reducing the pollution of bauxite acid leaching waste residue.

6. A bauxite acid leaching waste slag type roadbed material, characterized in that: The bauxite acid leaching waste slag type roadbed material contains the bauxite acid leaching waste slag modified curing agent according to claim 1 or 2.

7. The bauxite acid leaching waste slag type roadbed material according to claim 6, characterized in that: The bauxite acid leaching waste residue modified curing agent accounts for 5-10wt% in the bauxite acid leaching waste residue type roadbed material.

8. Use of the bauxite acid leaching waste slag type roadbed material according to claim 6 or 7 in highway roadbed filling engineering.

9. A method for using the bauxite acid leaching waste slag type roadbed material according to claim 6 or 7, characterized in that: The following steps are involved: The bauxite acid leaching waste residue is mixed with the bauxite acid leaching waste residue modified curing agent, wetted, laid and cured.

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