A high-dosage and high-strength environmental protection non-fired brick based on electrolytic manganese residue and its preparation method

Abstract

The present invention discloses a high-loading and high-strength electrolytic manganese slag-based environmentally friendly non-fired brick and a preparation method thereof. The electrolytic manganese slag, cement, and aggregate are mixed evenly to obtain dry materials; after the calcium oxide-based curing agent, expansion agent, heavy metal inhibitor, and water are stirred evenly, they are fully stirred with the dry materials to obtain a slurry; after the slurry is pressed into shape and cured, a non-fired brick with a high electrolytic manganese slag content, high strength, and heavy metal leaching results meeting the requirements specified in HJ 1241-2022 "Technical Specification for Pollution Control of Manganese Slag" is obtained. Compared with the existing electrolytic manganese slag-based non-fired bricks, it can greatly increase the consumption of electrolytic manganese slag, and obtain non-fired bricks with better mechanical properties, green environmental protection, and well solve the problems of non-compliance of heavy metal leaching and poor performance of non-fired bricks caused by the high content of electrolytic manganese slag.

Description

Technical Field

[0001] The invention relates to an unburned brick, in particular to a high-dosage, high-strength electrolytic manganese slag-based environmentally friendly unburned brick, and also to a preparation method thereof, belonging to the technical field of solid waste resource utilization. Background Art

[0002] Electrolytic manganese slag refers to the solid waste produced by electrolytic reduction of manganate ions during the production of electrolytic manganese. For every ton of electrolytic manganese product produced from low-grade manganese ore, about 10 tons of electrolytic manganese slag will be formed. At present, the problems faced by electrolytic manganese slag are high output and serious secondary pollution. Electrolytic manganese slag contains a large amount of pollutants such as ammonia nitrogen, Mn, Cr, soluble sulfate, SeO2, etc. These pollutants are exposed to the environment without control, which will bring severe challenges to the human production environment.

[0003] In recent years, the country has put forward increasingly higher requirements for the harmlessness and resource utilization of electrolytic manganese slag, especially reflected in the introduction of some new standards, such as the "General Industrial Solid Waste Storage and Landfill Pollution Control Standards" and the "Manganese Slag Pollution Control Technical Specifications". These two standards have put forward higher and clearer requirements for the harmless disposal and resource utilization of electrolytic manganese slag, resulting in the existing manganese slag treatment and disposal technologies or methods being difficult to meet the relevant requirements.

[0004] Chinese patent (CN114890749A) discloses a kind of electrolytic manganese slag and waste clay brick double mixed unburned brick, the raw material components of which are: electrolytic manganese slag, waste sintered clay brick, clay ceramsite, cement and curing agent; the curing agent is aliphatic amine curing agent; the unburned brick includes the following mass percentage components: electrolytic manganese slag 15-35%, cement 8-15%, curing agent 0.5%-2%, waste sintered clay brick 40-66%, clay ceramsite 5-10%; the unburned brick is prepared by the following method: after mixing the raw materials including electrolytic manganese slag, cement, waste sintered clay brick and clay ceramsite evenly, adding curing agent and water to fully stir to obtain unburned brick slurry, and the unburned brick slurry is formed and cured to obtain unburned brick. This method uses electrolytic manganese slag as the unburned brick component, and can obtain 14.3-26.4MPa, but its electrolytic manganese slag accounts for a low proportion. It is well known in the industry that if the dosage of electrolytic manganese slag is increased, the compressive strength of unfired bricks will decrease. At the same time, the toxic substances contained in the electrolytic manganese slag will easily escape, causing environmental problems. Summary of the invention

[0005] Aiming at the problems existing in the prior art, the first object of the present invention is to provide an environmentally friendly non-fired brick based on electrolytic manganese residue. This non-fired brick has a high content of electrolytic manganese residue, and at the same time has high strength and the heavy metal leaching results meet the requirements specified in HJ1241-2022 "Technical Specification for Pollution Control of Manganese Residue". Compared with the existing non-fired bricks based on electrolytic manganese residue, it can greatly increase the consumption of electrolytic manganese residue, and obtain non-fired bricks with better mechanical properties, green and environmental protection, and well solve the problems such as unqualified heavy metal leaching and poor performance of non-fired bricks due to the high content of electrolytic manganese residue.

[0006] The second object of the present invention is to provide a preparation method for a high-content and high-strength environmentally friendly non-fired brick based on electrolytic manganese residue. This preparation method has the advantages of being simple and easy to implement, low production cost, high utilization rate of solid waste materials, friendly to the environment, and no secondary pollution, and is suitable for continuous industrial production.

[0007] To achieve the above technical objects, the present invention provides a high-content and high-strength environmentally friendly non-fired brick based on electrolytic manganese residue, which includes the main raw material component of electrolytic manganese residue, as well as the secondary raw material components of aggregate, cement, calcium oxide-based curing agent, expansion agent and heavy metal inhibitor; the heavy metal inhibitor is composed of sodium chloride, phosphate and aluminum silicate.

[0008] The high-doped and high-strength environmentally friendly non-fired bricks based on electrolytic manganese slag provided by the present invention use electrolytic manganese slag as the main raw material. In previous experimental studies, the doping amount of electrolytic manganese slag in non-fired bricks was not higher than 35%. When the doping amount of electrolytic manganese slag was too high, the strength of non-fired bricks was low, and the solidification effect of toxic substances such as heavy metals was poor. The key to the technical solution of the present invention is to activate the electrolytic manganese slag with calcium oxide-based curing agents, and at the same time use expansion agents and heavy metal inhibitors to modify it, which can greatly improve the mechanical strength of non-fired bricks and better stabilize toxic substances such as heavy metals in non-fired bricks, thereby greatly increasing the doping amount of electrolytic manganese slag in non-fired bricks, and the highest doping amount can be increased to 60%, effectively solving the problems such as easy leaching of heavy metals in non-fired bricks and deterioration of the performance of non-fired bricks due to too high doping amount of electrolytic manganese slag. In the raw material components of the non-fired bricks of the present invention, the electrolytic manganese slag is an active waste residue, and the content of silicon-aluminum compounds is as high as about 65%. These active substances can undergo secondary hydration with the hydration products of cement, thereby improving the strength of the brick body. The addition of calcium oxide-based curing agents can provide more calcium hydroxide to react with the active substances in the electrolytic manganese slag, and the reaction generates gel substances to wrap other aggregates, forming a high-density network structure. The addition of the expansion agent can make the brick body expand appropriately, overcoming the problems of cracking and leakage caused by the drying shrinkage of the brick body. The heavy metal inhibitor can well fix and stabilize heavy metals such as Mn and Cr or convert them into hydroxide precipitates. The aggregate plays a supporting role, transmits stress, and provides mechanical strength. In summary, the raw material components of the non-fired bricks of the present invention, as a complete non-fired brick formula, can greatly increase the doping amount of electrolytic manganese slag, obtain higher mechanical strength, and achieve heavy metal stabilization.

[0009] As a preferred solution, the heavy metal inhibitor is composed of sodium chloride, phosphate, and aluminum silicate in a mass ratio of 6-9:6-9:6-9. When the pH value of the internal environment of the non-fired brick is too low due to cement hydration, it will not only affect the development of the mechanical properties of the non-fired brick, but also increase the risk of heavy metal precipitation in the brick. On the contrary, when the pH value of the internal environment of the non-fired brick is too high due to cement hydration, it is easy to cause high alkali content in the non-fired brick to form efflorescence, which will have an adverse effect on its durability. Sodium chloride has strong stability. Adding sodium chloride can effectively overcome the above problems brought by cement hydration in non-fired bricks, and keep the pH value inside the brick body in a suitable weakly alkaline condition. Phosphate can provide phosphate ions to undergo complexation reactions with heavy metals under certain conditions and generate stable heavy metal phosphate minerals; aluminum silicate itself has a stable network structure that can adsorb the precipitated heavy metals. The combined use of the three is equivalent to giving triple insurance for inhibiting heavy metal dissolution: (1) stabilizing the pH value condition inside the brick body; (2) generating stable metal mineral salts; (3) the role of adsorbing pollutants.

[0010] As a preferred embodiment, the calcium oxide-based curing agent includes at least one of quicklime, calcium oxide, and slaked lime. The calcium oxide-based curing agent provides calcium hydroxide, which can activate the active substances in electrolytic manganese slag and participate in the hydration reaction with them. The reaction generates gel substances that wrap other aggregates, forming a high-density network structure, which can improve the mechanical strength. At the same time, it can provide an alkaline environment and play a role in stabilizing heavy metals.

[0011] As a preferred embodiment, the expansive agent is UEA expansive agent. The expansive agent can make the brick body expand appropriately, overcoming the problems of cracking and leakage caused by the drying shrinkage of the brick body.

[0012] As a preferred embodiment, the phosphate is sodium phosphate.

[0013] As a preferred embodiment, the high-ratio, high-strength electrolytic manganese slag-based environmentally friendly non-fired brick comprises the following raw material components by mass percentage: 35% - 60% of electrolytic manganese slag, 15% - 20% of cement, 20% - 40% of aggregate, 0.5% - 2.5% of calcium oxide-based curing agent, 0.5% - 2.0% of expansive agent, and 0.3% - 2.5% of heavy metal inhibitor; measured based on the total mass of 100%. Further preferably, the high-ratio, high-strength electrolytic manganese slag-based environmentally friendly non-fired brick is composed of the following raw material components by mass percentage: 45% - 55% of electrolytic manganese slag, 15% - 20% of cement, 25% - 35% of aggregate, 0.8% - 1.5% of calcium oxide-based curing agent, 0.5% - 1.0% of expansive agent, and 0.5% - 1.8% of heavy metal inhibitor, measured based on the total mass of 100%. If the content of the calcium oxide-based curing agent is too high, since the reaction of calcium oxide is exothermic, thermal expansion will occur inside the brick body, generating microcracks, which will have an adverse effect on the brick body performance. At the same time, if the content of the calcium oxide-based curing agent is too high, a large amount of calcium carbonate substances will be generated inside the brick body, and the large generation of these substances will cause large-area efflorescence of the brick body. If the content of the calcium oxide-based curing agent is too low, the generated calcium hydroxide substances are not sufficient for the secondary hydration of the active silicon-aluminum compounds in the electrolytic manganese slag. The expansive agent can reduce the cracks caused by the early drying shrinkage of the brick body, and can also reduce the pores of the brick body and its bound water content, thus improving the water resistance. At the same time, the expansive agent can prevent early drying shrinkage and change the internal pore structure of the brick body, thereby obtaining a lower water absorption rate and reducing the freeze-thaw strength loss of the brick body.

[0014] As a preferred embodiment, the electrolytic manganese slag is roasted electrolytic manganese slag with a particle size of 1 - 5 mm and a silicon-aluminum compound content of ≥ 55%. The water content of the electrolytic manganese slag is not higher than 0.5%.

[0015] As a preferred embodiment, the average particle size of the aggregate is 0.5 - 3.0 mm. The water content of the aggregate is lower than 1%. The aggregate is machine-made sand.

[0016] As a preferred solution, the cement is ordinary Portland cement, such as PO.42.5.

[0017] The present invention also provides a preparation method of a high-ratio and high-strength electrolytic manganese residue-based environmentally friendly non-fired brick. The method includes mixing electrolytic manganese residue, cement, and aggregate evenly to obtain dry material; after uniformly stirring calcium oxide-based curing agent, expansive agent, heavy metal inhibitor, and water, fully stirring with the dry material to obtain slurry; after pressing and curing the slurry, the brick is obtained.

[0018] During the preparation process of the non-fired brick of the present invention, the calcium oxide-based curing agent, expansive agent, heavy metal inhibitor, etc. are first made into slurry and then mixed and reacted with raw materials such as electrolytic manganese residue. The main purpose is that the calcium oxide-based curing agent, expansive agent, heavy metal inhibitor, etc. are fully dissolved and dispersed in water, so that the functions of these additives can be better exerted, making the curing reaction more complete.

[0019] As a preferred solution, the mass ratio of water to material of the slurry is 0.10 - 0.18.

[0020] As a preferred solution, the pressure for pressing and forming is 15 - 30 MPa, and the time is 3.0 - 8.0 s.

[0021] As a preferred solution, the curing method is indoor curing, the curing temperature is 15 - 28 °C, and the relative humidity for curing is 40 - 80%.

[0022] As a preferred solution, the stirring conditions are: rotation speed 25 - 41 r / min, and time 3.0 - 5.5 min.

[0023] The present invention provides a detailed process of a preparation method of a high-ratio and high-strength electrolytic manganese residue-based environmentally friendly non-fired brick, including: 1) Pretreatment: uniformly mixing a calcium oxide-based curing agent, an expansive agent, and a heavy metal inhibitor in water in a certain proportion to form slurry. 2) Mixing and stirring: mixing electrolytic manganese residue, cement, and aggregate in a certain proportion, and obtaining brick-making dry material after stirring for 4.0 min at a rotation speed of 41 r / min under normal temperature and pressure by a mixer. Pouring the slurry into the brick-making dry material, and obtaining brick-making slurry after stirring for 3.5 min at a rotation speed of 41 r / min under normal temperature and pressure by a mixer. 3) Block forming: first pouring the well-stirred brick-making slurry into a mold, vibrating for 5.0 s by a forming machine to mix evenly, forming by adjusting the pressure to 20 MPa, vibrating on a vibrating platform for 1.2 s, and pressing by a top pressure head for 3.2 s by a block forming machine, and sending it to a finished product palletizing system by a walking machine table for automatic demolding. 4) The non-fired green road brick is cured indoors naturally, avoiding direct sunlight. The product needs to be watered once a day in the first two weeks to maintain humidity, and then only needs to be cured by covering with a film to obtain the product.

[0024] The reason why the high-dosage and high-strength electrolytic manganese residue-based environmentally friendly non-fired bricks prepared by the present invention have such excellent properties is that a calcium oxide-based curing agent is used to activate the electrolytic manganese residue to promote the curing reaction, and at the same time, an expansive agent and heavy metals are used to modify it. It is detected that the electrolytic manganese residue contains a large amount of silicon-aluminum compounds. Although these compounds can be activated by cement to undergo secondary hydration to improve the hardness of the consolidated body, the activation ability of cement is limited. The addition of the calcium oxide-based curing agent can greatly activate the electrolytic manganese residue. Calcium oxide can provide more calcium hydroxide to react with the active silicon-aluminum compounds in the electrolytic manganese residue, and the reaction generates a gelling substance to wrap other aggregates, forming a high-density network structure. The addition of a concrete expansive agent can make the brick body expand appropriately to overcome the problems of cracking and leakage caused by the drying shrinkage of the brick body. The heavy metal inhibitor can chelate and solidify heavy metal ions such as Mn and Cr well at room temperature, or convert the heavy metal ions into hydroxide precipitates and precipitate them out.

[0025] Compared with the prior art, the beneficial technical effects brought by the present invention are as follows:

[0026] 1) The raw materials of the high-dosage and high-strength electrolytic manganese residue-based environmentally friendly non-fired bricks provided by the present invention are widely sourced, low in cost, and the preparation method is simple. Traditional forming and curing methods can be adopted, which is conducive to large-scale production.

[0027] 2) The high-dosage and high-strength electrolytic manganese residue-based environmentally friendly non-fired bricks provided by the present invention have a high doping amount of electrolytic manganese residue. The key is to use a calcium oxide-based curing agent to activate the electrolytic manganese residue to promote the curing reaction, and at the same time, an expansive agent and a heavy metal inhibitor are used to modify it, greatly improving the mechanical strength of the non-fired bricks and reducing the leaching toxicity of the non-fired bricks, effectively solving the technical problems of poor heavy metal stabilization effect and performance decline caused by the high dosage of electrolytic manganese residue. The high-dosage and high-strength non-fired environmentally friendly bricks can be widely used in low-rise civil buildings, urban pedestrian walkways, parks, campuses, commercial street pavements and other occasions, realizing the resource utilization of solid waste materials.

[0028] 3) The 28-day compressive strength of the high-dosage and high-strength electrolytic manganese residue-based environmentally friendly non-fired bricks provided by the present invention is 41.6 MPa, reaching the MU40 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks". The heavy metal leaching results meet the requirements specified in HJ 1241-2022 "Technical Specifications for Pollution Control of Manganese Residue", and the production investment cost is low. The cost of each green and environmentally friendly non-fired brick is less than 0.3 yuan, which is suitable for large-scale, continuous and industrial production. Specific embodiments

[0029] For better understanding of the present invention by those skilled in the art, the present invention will be further described in detail below in conjunction with the following embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0030] In the following embodiments, commercial reagents are used if not otherwise specified.

[0031] In the following embodiments, the moisture content of electrolytic manganese slag and machine-made sand is lower than 0.5%.

[0032] Example 1

[0033] Raw material ratio: electrolytic manganese slag 55% (particle size 1 - 5 mm), ordinary Portland cement PO.42.5 20%, machine-made sand 20% (particle size 0.5 - 3 mm), slaked lime 2%, UEA expansive agent 1.2%, heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate: aluminum silicate = 1:1:1) 1.8%.

[0034] Table 1 Main chemical composition of electrolytic manganese slag

[0035]

[0036] Table 2 Physical properties of electrolytic manganese slag

[0037]

[0038] The preparation steps are as follows:

[0039] 1) Pretreatment: Mix calcium oxide-based curing agent, expansive agent and heavy metal inhibitor in water in a set ratio to form a slurry.

[0040] 2) Mixing and stirring: Mix electrolytic manganese slag, cement and aggregate in a set ratio, and obtain dry brick-making materials after stirring in a mixer at normal temperature and pressure for 4.0 min with a rotation speed of 41 r / min. Pour the slurry into the dry brick-making materials, and obtain brick-making slurry (water-to-material mass ratio is 0.15) after stirring in a mixer at normal temperature and pressure for 3.5 min with a rotation speed of 41 r / min.

[0041] 3) Block forming: First, pour the well-stirred brick-making slurry into a mold, mix it evenly by vibrating for 5.0 s by a forming machine, form it by adjusting the pressure of the block forming machine to 20 MPa, vibrating the vibrating platform for 1.2 s, and pressing down by the upper pressing head for 3.2 s. Then, send it to the finished product stacking system by a walking machine table for automatic demoulding.

[0042] 4) The non-fired green road bricks are cured indoors and naturally, avoiding direct sunlight. They need to be watered once a day for the first two weeks to maintain humidity (relative humidity is about 60%), and then only need to be cured by covering with a film to obtain. They can be shipped out after 28 days.

[0043] The measured 28-day compressive strength of the finished product is 41.65 MPa, reaching the MU40 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks".

[0044] Table 3 Test results of heavy metal leaching toxicity of bricks in Example 1

[0045]

[0046] Reference standard: HJ 1241-2022 "Technical Specification for Manganese Slag Pollution Control"

[0047] Example 2

[0048] Raw material ratio: (The properties of raw materials are the same as in Example 1)

[0049] Electrolytic manganese slag 50% (particle size 1 - 5 mm), ordinary Portland cement PO.42.5 20%, machine-made sand 26% (particle size 0.5 - 3 mm), slaked lime 1.0%, UEA expansion agent 0.6%, heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate: aluminum silicate = 1:1:1) 2.4%.

[0050] The preparation steps refer to Example 1.

[0051] The measured 28-day compressive strength of the finished product is 42.77 MPa, reaching the MU40 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks".

[0052] Table 4 Test results of heavy metal leaching toxicity of bricks in Example 2

[0053]

[0054] Reference standard: HJ 1241-2022 "Technical Specification for Manganese Slag Pollution Control"

[0055] Table 5 Test results of performance of non-fired bricks in Example 2

[0056]

[0057]

[0058] Example 3

[0059] Raw material ratio (The properties of raw materials are the same as in Example 1):

[0060] 40% electrolytic manganese slag (particle size 1 - 5 mm), 20% ordinary Portland cement PO.42.5, 36% machine-made sand (particle size 0.5 - 3 mm), 0.6% slaked lime, 1.0% UEA expansion agent, 2.4% heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate: aluminum silicate = 7:8:9).

[0061] For the preparation steps, refer to Example 1.

[0062] The measured 28-day compressive strength of the finished product is 46.82 MPa, reaching the MU40 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks".

[0063] Table 6 Test results of heavy metal leaching toxicity of bricks in Example 3

[0064]

[0065] Reference standard: HJ 1241-2022 "Technical Specification for Pollution Control of Manganese Slag"

[0066] Example 4

[0067] Raw material ratio (the properties of raw materials are the same as in Example 1):

[0068] 35% electrolytic manganese slag (particle size 1 - 5 mm), 20% ordinary Portland cement PO.42.5, 41% machine-made sand (particle size 0.5 - 3 mm), 0.8% slaked lime, 1.4% UEA expansion agent, 1.8% heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate: aluminum silicate = 1:1:1).

[0069] For the preparation steps, refer to Example 1.

[0070] The measured 28-day compressive strength of the finished product is 49.94 MPa, reaching the MU40 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks".

[0071] According to the test methods required by the corresponding national standards, the heavy metal leaching toxicity of the bricks and the properties of the non-fired bricks obtained from their preferred embodiments were detected respectively. The test results are as follows in the table:

[0072] Table 7 Test results of heavy metal leaching toxicity of bricks in Example 4

[0073]

[0074] Reference standard: HJ 1241-2022 "Technical Specification for Pollution Control of Manganese Slag"

[0075] Table 8 Test results of properties of non-fired bricks in Example 4

[0076]

[0077] Comparative Example 1

[0078] Raw material ratio (the properties of raw materials are the same as in Example 1):

[0079] Electrolytic manganese slag 55% (particle size 1 - 5 mm), ordinary Portland cement PO.42.5 20%, manufactured sand 21.8% (particle size 0.5 - 3 mm), slaked lime 2.0%, UEA expansion agent 1.2%, heavy metal inhibitor 0%.

[0080] The preparation steps refer to Example 1.

[0081] The measured 28 - day compressive strength of the finished product is 22.51 MPa, only reaching the MU20 strength grade specified in GB / T 21144 - 2007 "Solid Concrete Bricks". All properties of the non - fired bricks meet the national standards, but the leaching of Mn ions reaches 1.72 mg / L, Cr is 0.56 mg / L, and ammonia nitrogen is 1.47 mg / L, respectively exceeding the national standard limit values of 1.0 mg / L, 0.3 mg / L, and 1.0 mg / L.

[0082] Comparative Example 2

[0083] Raw material ratio (the properties of raw materials are the same as in Example 2):

[0084] Electrolytic manganese slag 50% (particle size 1 - 5 mm), ordinary Portland cement PO.42.5 20%, manufactured sand 26.0% (particle size 0.5 - 3 mm), slaked lime 1.0%, UEA expansion agent 0.6%, heavy metal inhibitor (sodium phosphate: aluminum silicate mass ratio = 1:1) 2.4%.

[0085] The preparation steps refer to Example 2.

[0086] The measured 28 - day compressive strength of the finished product is 24.70 MPa, only reaching the MU20 strength grade specified in GB / T 21144 - 2007 "Solid Concrete Bricks". All properties of the non - fired bricks meet the national standards, but the leaching of Mn ions reaches 1.31 mg / L, and ammonia nitrogen is 1.44 mg / L, respectively exceeding the national standard limit values of 1.0 mg / L and 1.0 mg / L.

[0087] Comparative Example 3

[0088] Raw material ratio (the properties of raw materials are the same as in Example 3): Electrolytic manganese slag 40% (particle size 1 - 5 mm), ordinary Portland cement PO.42.5 20%, manufactured sand 36% (particle size 0.5 - 3 mm), slaked lime 0.6%, UEA expansion agent 1.0%, heavy metal inhibitor (sodium chloride: aluminum silicate mass ratio = 7:9) 2.4%.

[0089] Refer to Example 3 for the preparation steps.

[0090] The measured 28-day compressive strength of the finished product is 36.39 MPa, only reaching the MU30 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks". All properties of the non-fired bricks meet the national standards, but the leaching of Mn ions reaches 1.24 mg / L and that of Cr is 0.47 mg / L, respectively exceeding the national standard limit values of 1.0 mg / L and 0.3 mg / L.

[0091] Comparative Example 4

[0092] Raw material ratio (the properties of raw materials are the same as in Example 4):

[0093] 35% electrolytic manganese slag (particle size 1 - 5 mm), 20% ordinary Portland cement PO.42.5, 41% machine-made sand (particle size 0.5 - 3 mm), 0.8% slaked lime, 1.4% UEA expansion agent, 1.8% heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate = 1:1).

[0094] Refer to Example 4 for the preparation steps.

[0095] The measured 28-day compressive strength of the finished product is 38.14 MPa, only reaching the MU30 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks". All properties of the non-fired bricks meet the national standards, but the leaching of Mn ions reaches 1.33 mg / L and that of Cr is 0.36 mg / L, respectively exceeding the national standard limit values of 1.0 mg / L and 0.3 mg / L.

[0096] Comparative Example 5

[0097] Raw material ratio (the properties of raw materials are the same as in Example 2):

[0098] 50% electrolytic manganese slag (particle size 1 - 5 mm), 20% ordinary Portland cement PO.42.5, 26.6% machine-made sand (particle size 0.5 - 3 mm), 1.0% slaked lime, 0.0% UEA expansion agent, 2.4% heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate: aluminum silicate = 1:1:1).

[0099] Refer to Example 2 for the preparation steps.

[0100] The measured 28-day compressive strength of the finished product is 25.22 MPa, only reaching the MU20 strength grade specified in GB / T 21144-2007 "Solid Concrete Bricks". The leaching of heavy metals and ammonia nitrogen all meets the national standards. However, the softening coefficient is 0.73 and the freeze-thaw strength loss is 32%, not meeting the minimum national standard requirements of 0.8 and 25%.

[0101] Comparative Example 6

[0102] Raw material ratio (the properties of raw materials are the same as those in Example 4):

[0103] 35% electrolytic manganese slag (particle size 1 - 5 mm), 20% ordinary Portland cement PO.42.5, 42.4% manufactured sand (particle size 0.5 - 3 mm), 0.8% slaked lime, 0.0% UEA expansion agent, 1.8% heavy metal inhibitor (mass ratio of sodium chloride: sodium phosphate: aluminum silicate = 1:1:1).

[0104] For the preparation steps, refer to Example 4.

[0105] The measured 28 - day compressive strength of the finished product is 47.31 MPa, reaching the strength grade of MU40 specified in GB / T 21144 - 2007 "Solid Concrete Bricks". The leaching of heavy metals and ammonia nitrogen both meets the national standards. However, the softening coefficient is 0.77 and the freeze - thaw strength loss is 27%, not meeting the minimum national standard requirements of 0.8 and 25%.

[0106] When no curing agent, modifier, and heavy metal inhibitor are incorporated into the non - fired brick or only a single one is incorporated, the brick body performance is not ideal.

[0107] The above embodiments are only exemplary descriptions of this application and do not limit its protection scope. Those skilled in the art can also make partial changes to it. As long as it does not exceed the spiritual essence of this application, it is within the protection scope of this application.

Claims

1. A high-loading and high-strength environmentally friendly non-fired brick based on electrolytic manganese residue, characterized in that: It contains the following raw material components by mass percentage: 35% - 60% of electrolytic manganese slag, 15% - 20% of cement, 20% - 40% of aggregate, 0.5% - 2.5% of calcium oxide-based curing agent, 0.5% - 2.0% of expansive agent, and 0.3% - 2.5% of heavy metal inhibitor; The heavy metal inhibitor is composed of sodium chloride, phosphate, and aluminum silicate in a mass ratio of 6 - 9:6 - 9:6 - 9; the calcium oxide-based curing agent includes at least one of quicklime, calcium oxide, and slaked lime; The expansive agent is UEA expansive agent.

2. The environmentally friendly non-fired brick based on high-ratio and high-strength electrolytic manganese residue according to claim 1, characterized in that: It is composed of the following raw material components by mass percentage: 45% - 55% of electrolytic manganese slag, 15% - 20% of cement, 25% - 35% of aggregate, 0.8% - 1.5% of calcium oxide-based curing agent, 0.5% - 1.0% of expansive agent, and 0.5% - 1.8% of heavy metal inhibitor.

3. A high-ratio, high-strength electrolytic manganese slag-based environmentally friendly non-fired brick according to claim 2, characterized in that: The electrolytic manganese slag is roasted electrolytic manganese slag with a particle size of 1 - 5 mm and a silicon-aluminum compound content of ≥55%; The average particle size of the aggregate is 0.5 - 3.0 mm.

4. The preparation method of a high-loading and high-strength environmentally friendly non-fired brick based on electrolytic manganese residue according to any one of claims 1 to 3, characterized in that: Mix the electrolytic manganese slag, cement, and aggregate evenly to obtain dry material; after stirring the calcium oxide-based curing agent, expansive agent, heavy metal inhibitor, and water evenly, fully stir with the dry material to obtain slurry; after pressing and curing the slurry, it is obtained.

5. The preparation method of a high-dosage and high-strength electrolytic manganese residue-based environmentally friendly non-fired brick according to claim 4, characterized in that: The mass ratio of water to material of the slurry is 0.10 - 0.

18.

6. The preparation method of a high-content and high-strength electrolytic manganese slag-based environmentally friendly non-fired brick according to claim 4, characterized in that: The pressure for pressing and forming is 15 - 30 MPa, and the time is 3.0 - 8.0 s.

7. The preparation method of a high-dosage and high-strength environmentally friendly non-fired brick based on electrolytic manganese residue according to claim 4, characterized in that: The curing method is indoor curing, the curing temperature is 15 - 28 °C, and the relative humidity for curing is 40 - 80%.

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