Low-carbon cement and preparation method thereof

Abstract

The invention relates to low-carbon cement, which is prepared from the following raw material components in parts by mass: 80 to 92 parts of low-carbon cement clinker, 5 to 15 parts of neutralization slag and 3 to 10 parts of flotation quartz tailings, wherein the low-carbon cement clinker is prepared from the following raw material components in percentage by mass: 5 to 15 percent of copper tailings, 10 to 35 percent of copper tailing mineral separation middlings and 55 to 80 percent of neutralization slag. According to the invention, the copper tailings and the neutralization slag are utilized as raw materials of the low-carbon cement clinker in a quality-divided gradient manner, so that the low-carbon cement is produced. According to the raw material compounding, effective components of the copper tailings and the neutralization slag can be fully utilized, the lime saturation coefficient, the silicon rate and the aluminum oxygen rate of the low-carbon cement clinker all meet the requirements, the cement with excellent physical and chemical properties can be obtained without adopting additional raw materials such as clay and limestone, a large amount of solid waste is consumed, the pressure of a tailing pond is reduced, and meanwhile, the cost is reduced. The sustainable development of the cement industry is also facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste application, and in particular to low-carbon cement and a preparation method thereof. Background Art

[0002] With the large-scale development of mineral resources, a large amount of tailings are inevitably produced. Among them, copper tailings are industrial waste in the form of slurry discharged after copper ore is crushed, ground and flotated. The output of copper tailings is huge, but the current comprehensive utilization rate is less than 10%. Unusable copper tailings are mostly stored in tailings ponds and dams, but long-term stacking will not only occupy a large amount of land resources and pollute the environment, but also pose a safety hazard. At the same time, chemical and metallurgical production will produce a large amount of acidic wastewater and waste gas, which are usually treated by lime neutralization. In this process, a large amount of waste slag (neutralized slag, the main component of which is CaSO 4 ·2H 2 O, CaCO 3 ), these waste slags can only be transported to the tailings pond for storage, which increases the storage capacity pressure of the tailings pond.

[0003] Therefore, it is of great social significance to comprehensively and effectively utilize copper tailings and neutralization slag to achieve large-scale disposal of solid waste, but there is little related research at present.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a low-carbon cement and a preparation method thereof.

[0006] The technical solution adopted by the present invention is:

[0007] In one aspect, the present invention provides a low carbon cement, the raw material components comprising, by weight:

[0008] 80-92 parts of low carbon cement clinker, 5-15 parts of neutralized slag, 3-10 parts of flotation quartz tailings;

[0009] The raw material components of the low carbon cement clinker include, by mass percentage:

[0010] Copper tailings 5-15%, copper tailings dressing middlings 10-35%, neutralized slag 55-80%.

[0011] The low-carbon cement proposed in the present invention utilizes copper tailings (middlings and quartz tailings obtained by ore dressing, and then quartz tailings are floated) and neutralized slag as raw materials for low-carbon cement clinker in a quality-graded and cascaded manner, thereby producing low-carbon cement. The above raw material compounding can fully utilize the effective components of copper tailings and neutralized slag, and the lime saturation coefficient KH, silicon content SM and aluminum oxygen content IM of the low-carbon cement clinker all meet the requirements. Cement with excellent physical and chemical properties can be obtained without using additional raw materials such as clay and limestone, which not only consumes a large amount of solid waste and reduces the pressure of the tailings pond, but also is conducive to the sustainable development of the cement industry.

[0012] Preferably, the neutralized slag is solid waste produced after acidic wastewater and waste gas in the chemical and metallurgical industries are neutralized by lime, and its chemical composition includes, by mass percentage: CaO 40-50%, SO 3 30-40%, Fe 2 O 3 20-30%, SiO 2 1-4%.

[0013] Preferably, the chemical composition of the flotation quartz tailings includes, by mass percentage: SiO 2 83-98%, Al 2 O 3 0.2-3%.

[0014] Preferably, the chemical composition of the copper tailings includes, by mass percentage: SiO 2 55-81%, Al 2 O 3 10-15%, K 2 O0.5-3%, Fe 2 O 3 1-5%.

[0015] Preferably, the chemical composition of the copper tailings ore includes, by mass percentage: SiO 2 45-73%, Al 2 O 3 3-11%, K 2 O0.1-1%, Fe 2 O 3 0.3-3%.

[0016] Preferably, the neutralized slag is subjected to a modification treatment, wherein the modification treatment is at least one of a heat treatment, a mechanical treatment and a chemical excitation treatment.

[0017] Preferably, the flotation quartz tailings are subjected to activation treatment, and the activation treatment is thermal activation and / or mechanical activation.

[0018] Preferably, the raw material components of the low carbon cement clinker further include, by mass percentage: 2-9% of flotation quartz tailings, 3-20% of phosphite black powder leaching slag;

[0019] The chemical components of the phosphite black powder leaching residue include, by mass percentage, 75-93% graphite, 0.2-3% lithium iron phosphate, and 3-21% water.

[0020] Another aspect of the present invention provides a method for preparing low carbon cement as described in any one of the above technical solutions, comprising the following steps:

[0021] S1. Mixing the raw material components of the low-carbon cement clinker according to mass percentage, and crushing, ball milling, and roasting in sequence to obtain low-carbon cement clinker;

[0022] S2. The low carbon cement clinker, neutralized slag and flotation quartz tailings are mixed according to parts by mass, and ball-milled to obtain low carbon cement.

[0023] Preferably, in step S1, the calcination temperature is 1380-1450° C., and the calcination time is 0.2-1 h. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the low carbon cement preparation process of Example 6 of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific examples, but the following examples should not be construed as limiting the present invention.

[0026] In one aspect, the present invention provides a low carbon cement, the raw material components comprising, by weight:

[0027] 80-92 parts of low carbon cement clinker, 5-15 parts of neutralized slag, 3-10 parts of flotation quartz tailings;

[0028] Among them, the raw material components of low carbon cement clinker include, by mass percentage:

[0029] Copper tailings 5-15%, copper tailings dressing middlings 10-35%, neutralized slag 55-80%.

[0030] In the present invention, the low-carbon cement clinker composed of three raw material components, copper tailings, copper tailings ore dressing, and neutralized slag, has a chemical composition including, by mass percentage, CaO 51-72%, SiO 2 19-24.3%, Al 2 O 3 5.5-7.9%,Fe 2 O 3 4.7-6.6%, SO3 0.02-2%. Under the above ratio, it is possible to control and design low-carbon cement clinker with lime saturation coefficient KH of 0.86-0.93, silicon rate SM of 2.0-2.38, and aluminum oxygen rate IM of 1.15-1.28, thereby meeting the requirements of traditional cement clinker, ensuring the basic performance of low-carbon cement, and coordinating the neutralized slag and flotation quartz tailings in the cement raw material components to further improve the quality of low-carbon cement.

[0031] In a preferred embodiment, the neutralized slag is solid waste produced after the acidic wastewater and waste gas of the chemical and metallurgical industries are neutralized by lime, and its chemical composition includes, by mass percentage: CaO 40-50%, SO 3 30-40%, Fe 2 O 3 20-30%, SiO 2 1-4%. In the present invention, on the one hand, the neutralized slag as a raw material component of low-carbon cement clinker can provide calcium source and iron source, replacing the traditional limestone to participate in the cement clinker sintering reaction; on the other hand, the neutralized slag as a raw material component of low-carbon cement, its gypsum component can play a role in adjusting the setting time of cement. The mass percentage of CaO in the neutralized slag can be any value of 40%, 42%, 44%, 46%, 48%, 50%, etc.; SO 3 The mass percentage of Fe can be any value among 30%, 32%, 33%, 35%, 37%, 40%, etc.; 2 O 3 The mass percentage can be any value among 20%, 22%, 24%, 26%, 28%, 30%, etc.; SiO 2 The mass percentage of can be any value among 1%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, etc., and the above list is not particularly limited. In addition, the chemical composition of the neutralized slag also includes the following by mass percentage: MgO 1-4%, Na 2 O0.5-3%, K 2 O 0.1-1%.

[0032] In a preferred embodiment, the chemical composition of the flotation quartz tailings includes, by mass percentage: SiO 2 83-98%, Al 2 O 3 0.2-3%. In the present invention, the flotation quartz tailings are minerals obtained by flotation of quartz tailings after copper tailings have been processed, and the chemical composition thereof also includes, by mass percentage: Fe 2 O 3 0.1-3%, Na 2 O 0.1-3%, K2 O 0.1-3%, CaO 0.1-2%, MgO 0.1-2%. The flotation quartz tailings in the low-carbon cement raw material components can supplement the silicon source, replace the traditional siliceous raw materials (such as clay), and react with the Ca(OH) 2 The reaction generates more cementitious substances CSH, which is beneficial to improve the later strength of cement. 2 The mass percentage of can be any value among 83%, 85%, 87%, 89%, 90%, 92%, 94%, 96%, 98%, etc., but is not limited to the above-mentioned values; 2 O 3 The mass percentage can be any value among 0.2%, 0.5%, 0.8%, 1.2%, 1.5%, 2.0%, 2.5%, 2.8%, 3.0% etc., but is not limited to the above-mentioned values.

[0033] In a preferred embodiment, the chemical composition of the copper tailings includes, by mass percentage: SiO 2 55-81%, Al 2 O 3 10-15%, K 2 O0.5-3%, Fe 2 O 3 The chemical composition of copper tailings also includes the following by mass percentage: CaO 1-8%, MgO 1-8%, SO 3 0.5-5%, CuO 0.1-1.5%, Na 2 O 0.5-3%. For example, in copper tailings, SiO 2 The mass percentage of Al can be any value among 55%, 58%, 60%, 65%, 67%, 70%, 75%, 77%, 81%, etc.; 2 O 3 The mass percentage of K can be any value among 10%, 11%, 12%, 13%, 14%, 15%, etc.; 2 The mass percentage of O can be any value among 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, etc.; Fe 2 O 3 The mass percentage can be any value among 1.0%, 2.0%, 3.0%, 4.0%, 5.0% etc., but is not limited to the above-mentioned values.

[0034] In a preferred embodiment, the chemical composition of the copper tailings ore includes, by mass percentage: SiO 2 45-73%, Al 2 O 3 3-11%, K2 O0.1-1%, Fe 2 O 3 In the present invention, the copper tailings dressing middlings are the middlings obtained after the copper tailings are beneficiated, and the chemical composition thereof further comprises, by mass percentage: CaO 1-6%, MgO 1-6%, SO 3 2-10%, CuO 0.5-5%. In the copper tailings ore, SiO 2 The mass percentage of Al can be any value among 45%, 48%, 50%, 53%, 57%, 60%, 63%, 68%, 70%, 73%, etc.; 2 O 3 The mass percentage of K can be any value among 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, etc.; 2 The mass percentage of O can be any value among 0.1%, 0.2%, 0.5%, 0.8%, 1.0%, etc.; Fe 2 O 3 The mass percentage can be any value among 0.3%, 0.7%, 1.0%, 1.5%, 1.7%, 2.0%, 2.3%, 2.7%, 3.0%, etc., without any particular limitation.

[0035] In a preferred embodiment, the neutralized slag is subjected to a modification treatment, and the modification treatment is at least one of a heat treatment, a mechanical treatment, and a chemical excitation treatment. In the present invention, the neutralized slag is modified in advance, so that the reaction activity of the neutralized slag can be improved. For example, the heat treatment mainly improves the efficiency of subsequent treatment by removing moisture from the neutralized slag. The heat treatment temperature can be 100-200°C, and the heat treatment time can be 1-4h; the mechanical treatment can be performed by ball milling or the like to crush the neutralized slag, and the subsequent chemical reaction activity can be improved by reducing the particle size and increasing the specific surface area. The particle size D50 of the neutralized slag after mechanical treatment can be ≤20μm; the chemical excitation treatment refers to directly mixing the neutralized slag with an activator in a certain mass ratio to improve the subsequent hydration activity of the neutralized slag. An alkaline activator or a sulfate activator can be used, wherein the alkaline activator can be NaOH, Na 2 CO 3 、Na 2 SiO 3 etc. Sulfate activator can be Na 2 SO 4 、CaSO 4 The amount of the activator can be 1-4% of the mass of the neutralized slag.

[0036] In a preferred embodiment, the flotation quartz tailings are activated, and the activation treatment is thermal activation and / or mechanical activation. In the present invention, the flotation quartz tailings are thermally activated in advance, and the reaction activity is ensured by removing the moisture in the flotation quartz tailings. The thermal activation temperature can be 100-150°C, and the thermal activation time can be 2-3h. It is necessary to avoid excessive temperature, which may lead to problems such as quartz crystal transformation; the flotation quartz tailings are mechanically activated by ball milling, etc., which can improve its reaction activity. The particle size D50 of the flotation quartz tailings after mechanical treatment can be ≤10μm.

[0037] In a preferred embodiment, the raw material components of low carbon cement clinker also include, by mass percentage: 2-9% of flotation quartz tailings, 3-20% of phosphorus iron black powder leaching slag;

[0038] The chemical composition of the leached slag of phosphorus iron black powder includes, by mass percentage, graphite 75-93%, lithium iron phosphate 0.2-3%, water 3-21%. In addition, it also includes metal impurities (such as Cu, Al, etc.) 0.1-5wt%, inorganic salts (such as sulfate, etc.) 0.2-3wt%, carbon-related impurities (such as amorphous carbon, etc.) 0.1-2wt%. In the present invention, flotation quartz tailings are introduced into the raw material components of low-carbon cement clinker because of its high-purity SiO 2 , which can improve its reactivity with CaO during clinker burning, which is beneficial to the formation of silicate minerals, and thus beneficial to the subsequent cement hydration effect. The graphite in the leached slag of iron phosphate black powder can act as a reducing agent in the clinker burning process, reducing SO 3 The lithium element in lithium iron phosphate has a mineralizing effect, which can stabilize the crystal structure of tricalcium silicate, and the iron element can promote the formation of tetracalcium aluminoferrate, thereby improving the strength of low carbon cement.

[0039] Another aspect of the present invention provides a method for preparing low carbon cement according to any one of the above technical solutions, comprising the following steps:

[0040] S1. Mixing the raw material components of low-carbon cement clinker according to mass percentage, and crushing, ball milling and roasting in sequence to obtain low-carbon cement clinker;

[0041] S2. low carbon cement clinker, neutralized slag and flotation quartz tailings are mixed according to mass parts, and ball-milled to obtain low carbon cement.

[0042] In the present invention, alumite concentrate is obtained in the copper tailings beneficiation process, which can be used to produce alum after impurity removal, hydrothermal reaction, etc., and quartz can be obtained in the quartz tailings flotation process; at the same time, the tail gas generated in the roasting process of step S1 can also be used for dry process (tail gas SO 2 and SO 3The sum of the volume fractions is 5-20%) to produce sulfuric acid, further improving the economic benefits.

[0043] In a preferred embodiment, in step S1, the calcination temperature is 1380-1450°C, and the calcination time is 0.2-1h. For example, the calcination temperature can be any value of 1380°C, 1390°C, 1400°C, 1410°C, 1420°C, 1430°C, 1440°C, 1450°C, etc., without particular limitation.

[0044] Example 1

[0045] A low carbon cement, the raw material components include, by weight:

[0046] 88 parts of low carbon cement clinker, 5 parts of neutralized slag, 7 parts of flotation quartz tailings;

[0047] Among them, the raw material components of low carbon cement clinker include, by mass percentage:

[0048] Copper tailings 15%, copper tailings dressing middlings 30%, neutralized slag 55%.

[0049] The chemical composition of the neutralized slag includes, by mass percentage: CaO 40%, SO 3 30%, Fe 2 O 3 20%, SiO 2 4%, MgO 4%, Na 2 O 1.5%, K 2 O 0.5%.

[0050] The chemical composition of flotation quartz tailings includes, by mass percentage: SiO 2 84%, Al 2 O 3 3%, Fe 2 O 3 3%, Na 2 O 3%, K 2 O 3%, CaO 2%, MgO 2%.

[0051] The chemical composition of copper tailings includes, by mass percentage: SiO 2 81%, Al 2 O 3 10%, K 2 O 0.5%, Fe 2 O 3 1%, CaO 4.4%, MgO 2%, SO 3 0.5%, CuO 0.1%, Na 2 O0.5%.

[0052] The chemical composition of the copper tailings ore includes, by mass percentage: SiO 2 73%, Al 2 O 3 11%, K 2 O0.1%, Fe 2 O 3 0.3%, CaO 5%, MgO 5%, SO 3 3.6%, CuO 2%.

[0053] It is prepared by the following method, comprising the following steps:

[0054] S1, copper tailings, copper tailings ore, and neutralized slag are mixed according to mass percentage, and crushed, ball-milled, and roasted (roasted at 1450° C. for 0.2 h) in sequence to obtain low-carbon cement clinker;

[0055] S2. low carbon cement clinker, neutralized slag and flotation quartz tailings are mixed according to mass parts, and ball-milled to obtain low carbon cement.

[0056] Example 2

[0057] The main difference between this embodiment and embodiment 1 is that the low carbon cement and the neutralized slag in the low carbon cement clinker are modified (heat treated at 150°C for 2h, then mechanically treated, and ball milled to a particle size D50 = 10 μm), and the chemical composition of the modified neutralized slag includes, by mass percentage: CaO 42%, SO 3 27%, Fe 2 O 3 21%, SiO 2 5%, MgO 1%, water 2.5%, Na 2 O1%, K 2 O 0.5%. The rest of the steps remained unchanged.

[0058] Example 3

[0059] The main difference between this embodiment and embodiment 1 is that the flotation quartz tailings in the low-carbon cement raw material component are activated (mechanical activation, ball milling to a particle size of D50 = 5 μm). The other steps remain unchanged.

[0060] Example 4

[0061] The main difference between this embodiment and embodiment 2 is that the flotation quartz tailings in the low-carbon cement raw material component are activated (mechanical activation, ball milling to a particle size of D50 = 5 μm). The other steps remain unchanged.

[0062] Example 5

[0063] The main difference between this embodiment and embodiment 4 is that the raw material components of low carbon cement clinker include flotation quartz tailings and phosphorus iron black powder leaching residue, wherein the chemical composition of phosphorus iron black powder leaching residue includes, by mass percentage: 93% graphite, 0.2% lithium iron phosphate, 6% water, 0.2% metal impurities, 0.4% inorganic salts, and 0.2% carbon related impurities. Specifically, the raw material components of low carbon cement clinker are adjusted to include, by mass percentage: 15% copper tailings, 25% copper tailings middlings, 55% neutralization residue, 2% flotation quartz tailings, and 3% phosphorus iron black powder leaching residue. The remaining steps remain unchanged.

[0064] Example 6

[0065] The main differences between this embodiment and embodiment 5 are that the dosage of each raw material, the modification treatment of the neutralization slag, and the activation treatment of the flotation quartz tailings are different.

[0066] A low carbon cement, the raw material components include, by weight:

[0067] 92 parts of low carbon cement clinker, 5 parts of modified neutralized slag, 3 parts of activated flotation quartz tailings;

[0068] Among them, the raw material components of low carbon cement clinker include, by mass percentage:

[0069] Copper tailings 5%, copper tailings dressing middlings 10%, modified neutralization slag 80%, flotation quartz tailings 2%, ferrophosphorus black powder leaching slag 3%.

[0070] The modified neutralized slag is heat treated at 150℃ for 2h, and then mixed with NaOH at a mass ratio of 1:0.02 for chemical excitation treatment (the chemical composition of the neutralized slag includes: CaO 45%, SO 3 30%, Fe 2 O 3 22%, SiO 2 1%, MgO 1.4%, Na 2 O 0.5%, K 2 O 0.1%), the chemical composition of the modified neutralized slag includes by mass percentage: CaO 53%, SO 3 15.1%, Fe 2 O 3 21%, SiO 2 5%, MgO 1%, water 2%, Na 2 O 2.8%, K 2 O0.1%.

[0071] The chemical composition of flotation quartz tailings includes, by mass percentage: SiO 2 98%、Al 2 O 30.2%, Fe 2 O 3 0.4%, Na 2 O 0.5%, K 2 O 0.5%, CaO 0.2%, MgO 0.2%.

[0072] The activated flotation quartz tailings are flotation quartz tailings that have been thermally activated at 120°C for 2 hours.

[0073] The chemical composition of copper tailings includes, by mass percentage: SiO 2 55%, Al 2 O 3 15%, K 2 O 0.5%, Fe 2 O 3 5%, CaO 8%, MgO 7%, SO 3 5%, CuO 1.5%, Na 2 O 3%.

[0074] The chemical composition of the copper tailings ore includes, by mass percentage: SiO 2 73%, Al 2 O 3 3%, K 2 O0.1%, Fe 2 O 3 0.3%, CaO 6%, MgO 6%, SO 3 8.6%, CuO 3%.

[0075] The chemical composition of the ferrophosphorus black powder leaching residue includes, by mass percentage, 93% graphite, 0.2% lithium iron phosphate, 6% water, 0.2% metal impurities, 0.4% inorganic salts, and 0.2% carbon-related impurities.

[0076] It is prepared by the following method (process flow chart see Figure 1 ), including the following steps:

[0077] S1, copper tailings, copper tailings ore, modified neutralization slag, flotation quartz tailings, and phosphorus iron black powder leaching slag are mixed according to mass percentage, and crushed, ball-milled, and roasted (roasted at 1380° C. for 1 h) in sequence to obtain low-carbon cement clinker;

[0078] S2. low carbon cement clinker, modified neutralized slag and activated flotation quartz tailings are mixed according to mass parts, and ball-milled to obtain low carbon cement.

[0079] According to production requirements, the chemical composition of low carbon cement clinker must meet the requirements of KH, SM and IM. The chemical composition of low carbon cement clinker prepared in Examples 1-5 is similar. Taking Example 4 as an example, the chemical composition of low carbon cement clinker includes, by mass percentage: CaO 64.4%, SiO 2 22.0%、Al 2 O 3 5.9%, Fe 2 O 3 4.9%, SO 3 2%; it is calculated that the low carbon cement clinker of Example 4 has KH=0.86, SM=2.04, and IM=1.20; the chemical composition of the low carbon cement clinker prepared in Example 6 includes, by mass percentage: CaO 66.5%, SiO 2 21.4%, Al 2 O 3 5.5%, Fe 2 O 3 4.7%, SO 3 0.02%; calculated, the low carbon cement clinker KH = 0.93, SM = 2.10, IM = 1.17 in Example 6. Therefore, the present invention can use waste copper tailings and neutralized slag as raw materials to prepare low carbon cement clinker, thereby producing high-quality low carbon cement.

[0080] Performance testing method:

[0081] The low carbon cement prepared in Examples 1-6 was subjected to performance tests, and the compressive strength of the cement was tested according to GB / T 17671-2021 "Test Method for Cement Mortar Strength (ISO Method)"; the standard consistency setting time of the cement was tested according to GB / T1346-2011 "Test Method for Water Consumption, Setting Time and Stability of Cement Standard Consistency"; and the magnesium oxide content, sulfur trioxide content and loss on ignition were determined according to GB / T 176-2017 "Cement Chemical Analysis Method".

[0082] Table 1

[0083]

[0084]

[0085] As shown in Table 1, the mechanical properties, setting time and other indicators of the low carbon cement prepared in Examples 1-6 meet the standard requirements of GB175-2023 "General Portland Cement" for 42.5 strength grade cement. Comparing Examples 1-4, it can be seen that compared with Example 1, Example 2 uses the modified neutralized slag as the raw material of low carbon cement clinker and low carbon cement, which has higher activity, so the early hydration rate and compressive strength of cement are better than those of Example 1; and Example 3 uses activated flotation quartz tailings as the raw material of low carbon cement, which has better reaction activity and can react with the hydration product Ca(OH) 2 More cementitious substances are generated, which accelerates the cement hydration process and compressive strength; Example 4 simultaneously modifies and activates the low-carbon cement clinker, the neutralized slag in the low-carbon cement, and the flotation quartz tailings in the low-carbon cement, so its various properties are better than those of Examples 1-3. Comparing Examples 4-6, it can be seen that since the flotation quartz tailings (replacing the SiO2 in the copper tailings) are additionally added to the raw material components of the low-carbon cement clinker of Example 5, 2 ) and ferrophosphorus black powder leaching residue, can promote C 3 Generation and structural optimization of S, and slightly increased C 4 AF content, therefore, relative to Example 4, it can accelerate the early hydration rate and compressive strength of low carbon cement, and due to C 4 The presence of AF also improves the later compressive strength of Example 5. Example 6 Since the KH and SM values ​​are higher than those of Example 5, the hydration rate and mechanical properties of the low carbon cement prepared therefrom are improved.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low carbon cement, characterized in that: The raw material components include, by mass: 80-92 parts of low carbon cement clinker, 5-15 parts of neutralized slag, 3-10 parts of flotation quartz tailings; The raw material components of the low carbon cement clinker include, by mass percentage: Copper tailings 5-15%, copper tailings dressing middlings 10-35%, neutralized slag 55-80%.

2. The low carbon cement according to claim 1, characterized in that: The neutralized slag is solid waste produced after acidic wastewater and waste gas in the chemical and metallurgical industries are neutralized by lime, and its chemical composition includes, by mass percentage: CaO 40-50%, SO3 30-40%, Fe2O3 20-30%, SiO2 1-4%.

3. The low carbon cement according to claim 1, characterized in that: The chemical composition of the flotation quartz tailings includes, by mass percentage, 83-98% SiO2 and 0.2-3% Al2O3.

4. The low carbon cement according to claim 1, characterized in that: The chemical components of the copper tailings include, by mass percentage, SiO2 55-81%, Al2O3 10-15%, K2O 0.5-3%, and Fe2O3 1-5%.

5. The low carbon cement according to claim 1, characterized in that: The chemical composition of the copper tailings ore includes, by mass percentage, SiO2 45-73%, Al2O3 3-11%, K2O 0.1-1%, and Fe2O3 0.3-3%.

6. The low carbon cement according to claim 1, characterized in that: The neutralized slag is subjected to a modification treatment, wherein the modification treatment is at least one of a heat treatment, a mechanical treatment and a chemical excitation treatment.

7. The low carbon cement according to claim 1, characterized in that: The flotation quartz tailings are activated, and the activation treatment is thermal activation and / or mechanical activation.

8. The low carbon cement according to claim 1, characterized in that: The raw material components of the low carbon cement clinker also include, by mass percentage: 2-9% of flotation quartz tailings, 3-20% of phosphite black powder leaching slag; The chemical components of the phosphite black powder leaching residue include, by mass percentage, 75-93% graphite, 0.2-3% lithium iron phosphate, and 3-21% water.

9. A method for preparing low carbon cement according to any one of claims 1 to 8, comprising the following steps: S1. Mixing the raw material components of the low-carbon cement clinker according to mass percentage, and crushing, ball milling, and roasting in sequence to obtain low-carbon cement clinker; S2. The low carbon cement clinker, neutralized slag and flotation quartz tailings are mixed according to parts by mass, and ball-milled to obtain low carbon cement.

10. The method for preparing low carbon cement according to claim 9, characterized in that: In step S1, the calcination temperature is 1380-1450° C., and the calcination time is 0.2-1 h.

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