A method for preparing general-purpose Portland cement clinker using ferronickel slag leaching residue

Abstract

The present invention discloses a method for preparing general-purpose Portland cement clinker using ferronickel slag leaching residue, relating to the fields of environmental protection and building materials. The method comprises: first, mixing ferronickel slag sulfuric acid leaching residue with blast furnace slag, lime, and a regulator, ball-milling the mixture, and then calcining it at high temperature; then rapidly cooling the calcined product; and finally grinding it to produce Portland cement clinker. The present invention utilizes a high-temperature multiphase reaction to convert the raw material into a cement phase containing active components such as tricalcium silicate, dicalcium silicate, and tetracalcium aluminoferrite. The ferronickel slag sulfuric acid leaching residue has a very small particle size and does not require grinding, allowing for large amounts of slag to be added and easily burned through. The main performance indicators of the produced Portland cement clinker meet the national standards for general-purpose Portland cement clinker. The present invention has important reference value for reducing the amount of ferronickel slag and has excellent market prospects and promotion value.

Description

Technical Field

[0001] The present invention relates to the fields of environmental protection and building materials, and in particular to a method for preparing universal Portland cement clinker by utilizing ferronickel slag leaching residue. Background Art

[0002] With the increasing depletion of nickel sulfide ore resources, laterite nickel ore has gradually become the raw material for the production of various nickel-based products. Ferronickel slag, an industrial waste product produced during the smelting of nickel-iron alloys, is discharged in significant quantities, becoming the second largest smelting slag source in the non-ferrous metals industry after red mud. However, ferronickel slag is still primarily stockpiled, occupying significant land and posing a serious threat to the surrounding ecological environment.

[0003] Existing research has investigated the use of ferronickel slag as a partial replacement for natural fine sand or as an admixture to improve concrete properties. While ferronickel slag can be used to produce autoclaved bricks, its MgO content is subject to certain restrictions. Furthermore, ferronickel slag can be used to produce glass-ceramics. However, due to its high MgO content, ferronickel slag is not suitable for direct production of Portland cement clinker. This is particularly true for ferronickel slag produced by the submerged arc furnace process commonly used in my country, where the MgO content typically exceeds 30%. my country's national standards for Portland cement clinker require a MgO content of less than 5%. Excessive MgO can cause volume expansion during the hardening of the cement paste, leading to cracking. This severely limits the allowable addition of ferronickel slag to Portland cement clinker, hindering its large-scale reduction. To enable the application of ferronickel slag in cement clinker production, the critical issue of high MgO content must be addressed.

[0004] The applicant previously used a sulfuric acid leaching-crystallization-washing process to recover magnesium from ferronickel slag and applied for a related patent, namely, "A method for recovering magnesium from ferronickel slag (CN111926193A)". After recovering the magnesium, the "ferronickel slag" is converted into "ferronickel slag sulfuric acid leaching residue". The MgO content in the leached residue is less than 10%, and the theoretical addition amount in the raw material formula for preparing cement clinker can reach up to 50%. This provides technical support for the practical application of the ferronickel slag full utilization technology for recovering magnesium from ferronickel slag and producing silicate cement clinker with the residual residue.

[0005] Therefore, the technical problem to be solved by the present invention is to solve the problem of sulfuric acid leaching residue produced after magnesium recovery from ferronickel slag (the leaching residue accounts for about 70% of the mass of the ferronickel slag raw material), so that it can be added in a larger amount as a raw material for preparing general-purpose Portland cement clinker, thereby providing a method for absorbing the ferronickel slag stock on a large scale. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the prior art and provide a method for preparing general-purpose Portland cement clinker using ferronickel slag leaching residue. The method relates to the fields of environmental protection and building materials. The method comprises: first, mixing ferronickel slag sulfuric acid leaching residue with blast furnace slag, lime, and a conditioning agent, ball milling the mixture, and then calcining the mixture at high temperature. The calcined mixture is then rapidly cooled, and finally ground to produce Portland cement clinker. The present invention utilizes a high-temperature multiphase reaction to convert the raw material into a cement phase containing active components such as tricalcium silicate, dicalcium silicate, and tetracalcium aluminoferrite. The ferronickel slag sulfuric acid leaching residue has a very small particle size and does not require grinding. A large amount of slag can be added, making it easy to burn through. The main performance indicators of the produced Portland cement clinker meet the national standards for general-purpose Portland cement clinker. The present invention has important reference value for reducing the amount of ferronickel slag and has excellent market prospects and promotion value.

[0007] In order to achieve the above technical effects, the following technical solutions are adopted:

[0008] A method for preparing general Portland cement clinker using ferronickel slag leaching residue comprises the following steps:

[0009] Step S1: Drying: drying the nickel-iron slag sulfuric acid leaching residue, Fe2O3, alumina Al2O3 and lime CaO at a certain temperature;

[0010] Step S2: ball milling: the nickel-iron slag sulfuric acid leaching residue obtained after drying in step S1, Fe2O3, alumina Al2O3 and lime CaO are mixed in a certain proportion and then ball milled for a certain time, and sieved after ball milling to obtain raw material powder;

[0011] Step S3: Briquetting: placing the raw material powder obtained in step S2 into a steel mold and pressing it into raw material blocks;

[0012] Step S4: calcining: calcining the raw material blocks prepared in step S3, taking them out immediately after calcination and keeping them warm, and rapidly cooling them to prepare Portland cement clinker;

[0013] Step S5: Gypsum is added to the Portland cement clinker fired in step S4, and then ball-milled to mix thoroughly. After ball-milling, the mixture is sieved to obtain universal Portland cement.

[0014] Furthermore, in the step S1, the nickel-iron slag sulfuric acid leaching residue, Fe2O3, alumina Al2O3 and lime CaO are dried at 100-120°C for 2-6 hours respectively.

[0015] Furthermore, in step S2, the mass of the nickel-iron slag sulfuric acid leaching residue added is 25-30% of the total amount of raw material powder, the Fe2O3 added is 2-5% of the total amount of raw material powder, the CaO added is 55-65% of the total amount of raw material powder, and the Al2O3 added is 4-10% of the total amount of raw material powder; the ball mill is a planetary ball mill; the rotation speed during ball milling is set to 250-400 r / min, the revolution speed is 400-600 r / min, the grinding time is 1-4h, and the ore is sieved with a 200-mesh sieve after ball milling; the mass of the sieve residue does not exceed 2% of the mass of the raw material before sieving; and the particle size of the raw material powder is less than 74 μm.

[0016] Furthermore, the pressure for pressing the raw material block in step S3 is 10-30 MPa.

[0017] Furthermore, the calcination in step S4 is carried out in a muffle furnace; the calcination temperature is 1350-1450° C.; the calcination is kept warm for 30-120 minutes; and the product is rapidly cooled by air cooling or other methods.

[0018] Furthermore, the mass ratio of gypsum added in step S5 is 3-7% of the silicate cement clinker; the ball mill is a planetary ball mill; the rotation speed during ball milling is set to 250-350 r / min, the revolution speed is 400-500 r / min, the grinding time is 1-3 hours, and after ball milling, the ore is sieved through a 200-mesh sieve, and the mass of the residue does not exceed 2% of the mass of the raw material before sieving; the particle size of the general silicate cement is less than 74 μm.

[0019] Furthermore, the chemical composition of the nickel iron slag sulfuric acid leaching residue is: 70-85wt% SiO2, 5-10wt% MgO, 2-5wt% Fe2O3, and 2-5wt% Al2O3; the physical phase components of the nickel iron slag sulfuric acid leaching residue are mainly amorphous SiO2, and contain a small amount of olivine structure Mg2SiO4 crystal phase.

[0020] Furthermore, the Fe2O3 is one or more of common Fe2O3 chemical reagent, blast furnace slag, steelmaking slag, ferroalloy smelting slag, and rust.

[0021] Furthermore, the lime CaO is one or more of common CaO chemical reagent, limestone, lime, high calcium tailings, and smelting slag.

[0022] Furthermore, the Al2O3 is one or more of common Al2O3 chemical reagent, fly ash, bauxite, and bauxite mud.

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

[0024] A method for preparing universal Portland cement clinker using ferronickel slag sulfuric acid leaching residue as raw material comprises the steps of raw material formula design, grinding, roasting and cooling.

[0025] The technical solution of the present invention has the following advantages:

[0026] 1. The present invention provides a method for preparing Portland cement clinker using nickel ferronickel slag sulfuric acid leaching residue as raw material. Compared with nickel ferronickel slag, the addition amount is significantly increased, and the theoretical addition amount can reach 50%. The actual addition amount depends on the composition of other ingredients and process parameters. In the present invention, the actual addition amount of nickel ferronickel slag sulfuric acid leaching residue is 25-30%;

[0027] 2. The present invention provides a method for preparing Portland cement clinker using ferronickel slag sulfuric acid leaching residue as raw material. In addition to using calcium-containing minerals such as limestone, solid waste can be used as raw material, thereby significantly reducing the cost of producing cement clinker.

[0028] 3. The present invention provides a method for preparing Portland cement clinker using ferronickel slag sulfuric acid leached residue as raw material. The particle size of the ferronickel slag sulfuric acid leached residue used is very fine, generally not exceeding 10 μm, and the particle size requirement for preparing cement clinker can be achieved without ball milling.

[0029] 4. The method provided by the present invention for preparing silicate cement clinker using nickel-iron slag sulfuric acid leaching residue as raw material is well compatible with the existing industrial method for preparing silicate cement clinker, can be produced using existing equipment, and is convenient for the industrial application of future scientific and technological achievements. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 1 is a process flow chart for preparing Portland cement clinker using nickel iron slag sulfuric acid leaching residue as raw material in the embodiment;

[0032] Figure 2 The XRD pattern of the nickel iron slag sulfuric acid leaching residue in the embodiment;

[0033] Figure 3 The XRD pattern of Portland cement clinker prepared using nickel-iron slag sulfuric acid leaching residue as raw material under different calcination temperature conditions is shown in the examples;

[0034] Figure 4: is a SEM image of Portland cement clinker prepared using nickel-iron slag sulfuric acid leaching residue as raw material at a roasting temperature of 1350° C. in the embodiment;

[0035] Figure 5 : is a SEM image of Portland cement clinker prepared using nickel-iron slag sulfuric acid leaching residue as raw material at a roasting temperature of 1400° C. in the examples;

[0036] Figure 6 : This is a SEM image of the Portland cement clinker prepared using nickel-iron slag sulfuric acid leaching residue as raw material at a roasting temperature of 1450°C in the examples. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0039] like Figure 1 As shown, the present invention provides a method for preparing silicate cement clinker using nickel-iron slag sulfuric acid leaching residue as raw materials, including the steps of designing the raw material composition formula, grinding, roasting, and rapid cooling to prepare silicate cement clinker.

[0040] The main chemical components of the nickel ferronickel slag sulfuric acid leaching residue used in the embodiment of the present invention are shown in Table 1. The XRD characteristics of the nickel ferronickel slag sulfuric acid leaching residue used in the embodiment of the present invention are shown in Table 1. Figure 2 shown.

[0041] Table 1 Chemical composition of nickel-iron slag sulfuric acid leaching residue

[0042]

[0043] The raw material formula used in this application is shown in Table 2:

[0044] Table 2 Raw material formula and main chemical components

[0045]

[0046] Example 1:

[0047] like Figure 1 As shown, according to Figure 1 The silicate cement clinker 1 was prepared according to the process shown and the proportions in Tables 1 and 2.

[0048] The following steps are involved:

[0049] S1. Drying: drying the nickel-iron slag, blast furnace slag, alumina and lime at 105°C for 3 hours.

[0050] S2, mixing: the ferronickel slag leached with sulfuric acid after drying in step S1, blast furnace slag, alumina and lime are mixed in a certain proportion and then ball-milled on a planetary ball mill. The rotation speed during ball milling is set to 350 r / min, the revolution speed is 400 r / min, and the grinding time is 3 h. After ball milling, the ore is sieved through a 200 mesh sieve to obtain ferronickel slag powder with a particle size of less than 74 μm.

[0051] In step S2, the material ratio is as follows: nickel iron slag sulfuric acid leaching residue is added in an amount of 26.4% of the total raw material, blast furnace slag is added in an amount of 8.7%, lime is added in an amount of 60.9%, and alumina is added in an amount of 3.8%.

[0052] S3. Briquetting: placing the raw material obtained in step S2 into a stainless steel mold and pressing it into raw material blocks at a pressure of 25 MPa.

[0053] S4, roasting: roasting the raw material block prepared in step S3 in a muffle furnace at a roasting temperature of 1400° C., taking it out of the furnace immediately after keeping it warm for 60 minutes, and rapidly cooling it with a fan to prepare Portland cement clinker 1.

[0054] S5. Add 7% gypsum to the Portland cement clinker 1 fired in step S4, and then mix thoroughly using a planetary ball mill. The rotation speed of the planetary ball mill is set to 300 r / min, the revolution speed is set to 400 r / min, and the grinding time is 1 hour. After ball milling, pass through a 200-mesh sieve to obtain Portland cement 1 with a particle size of less than 74 μm.

[0055] After testing, the phase structure of the prepared silicate cement clinker 1 is as follows Figure 3 The curve at 1400℃ shows that the clinker is composed of cement phases mainly composed of C3S and C2S. Figure 5 The SEM images in Figure 3 are consistent with the EDS analysis results in Table 3.

[0056] The f-CaO content in the clinker was determined using the glycerol method specified in the national standard (GB / T176-2017). The standard consistency water consumption, initial setting time, final setting time, and stability of the cement paste were tested according to the national standard (GB / T 1346-2001). The strength of the cement mortar was tested according to the national standard (GB / T 17671-1999). The test results are shown in Table 4. These results demonstrate that the main technical indicators meet the product strength grade 32.5 requirements specified in the national standard for general-purpose Portland cement (GB 175-2007).

[0057] Example 2:

[0058] like Figure 1 As shown, according to Figure 1 The silicate cement clinker 2 was prepared according to the process shown and the proportions in Tables 1 and 2.

[0059] The following steps are involved:

[0060] S1. Drying: drying the nickel-iron slag, blast furnace slag, alumina and lime at 105°C for 3 hours.

[0061] S2, mixing: the ferronickel slag leached with sulfuric acid after drying in step S1, blast furnace slag, alumina and lime are mixed in a certain proportion and then ball-milled on a planetary ball mill. The rotation speed during ball milling is set to 350 r / min, the revolution speed is 400 r / min, and the grinding time is 3 h. After ball milling, the ore is sieved through a 200 mesh sieve to obtain ferronickel slag powder with a particle size of less than 74 μm.

[0062] In step S2, the material ratio is as follows: nickel iron slag sulfuric acid leaching residue is added in an amount of 26.4% of the total raw material, blast furnace slag is added in an amount of 8.5%, lime is added in an amount of 61.2%, and alumina is added in an amount of 3.7%.

[0063] S3. Briquetting: placing the raw material obtained in step S2 into a stainless steel mold and pressing it into raw material blocks at a pressure of 25 MPa.

[0064] S4, roasting: the raw material block prepared in step S3 is roasted in a muffle furnace at a roasting temperature of 1450° C., and immediately taken out of the furnace after being kept warm for 60 minutes, and rapidly cooled by a fan to prepare Portland cement clinker 2.

[0065] S5: This step is the same as step S5 in Example 1.

[0066] After testing, the phase structure of the prepared silicate cement clinker 2 is as follows Figure 3 The curve at the temperature of 1450℃ shows that the cement phase is mainly composed of C3S and C2S. Figure 6 The SEM images in Figure 3 are consistent with the EDS analysis results in Table 3.

[0067] The performance test method is the same as that of Example 1. The results are shown in Table 4, which shows that the main technical indicators of the prepared Portland cement clinker 2 meet the product requirements of the strength grade of 32.5 in the national standard for general Portland cement (GB 175-2007).

[0068] Example 3:

[0069] like Figure 1 As shown, according to Figure 1 The silicate cement clinker 3 was prepared according to the process shown and the proportions in Tables 1 and 2.

[0070] The following steps are involved:

[0071] S1. Drying: dry the ferronickel slag, blast furnace slag, alumina and quicklime at 105°C for 3h.

[0072] S2, mixing: the ferronickel slag leached with sulfuric acid after drying in step S1, blast furnace slag, alumina and lime are mixed in a certain proportion and then ball-milled on a planetary ball mill. The rotation speed during ball milling is set to 250 r / min, the revolution speed is 400 r / min, the grinding time is 4 h, and after ball milling, the ore is passed through a 200 mesh sieve to obtain ferronickel slag powder with a particle size of less than 74 μm.

[0073] In step S2, the material ratio is as follows: nickel iron slag sulfuric acid leaching residue is added in an amount of 25.9% of the total raw material, blast furnace slag is added in an amount of 8.4%, lime is added in an amount of 62%, and alumina is added in an amount of 3.6%.

[0074] S3. Briquetting: placing the raw material obtained in step S2 into a stainless steel mold and pressing it into raw material blocks at a pressure of 30 MPa.

[0075] S4, roasting: roasting the raw material blocks prepared in step S3 in a muffle furnace at a roasting temperature of 1400° C., taking them out of the furnace immediately after keeping them warm for 90 minutes, and rapidly cooling them with a fan to prepare Portland cement clinker 3.

[0076] S5. Add 4% gypsum to the Portland cement clinker 3 fired in step S4, and then mix thoroughly using a planetary ball mill. The rotation speed of the planetary ball mill is set to 300 r / min, the revolution speed is set to 500 r / min, and the grinding time is 3 h. After ball milling, the mixture is sieved through a 200-mesh sieve to obtain Portland cement with a particle size of less than 74 μm.

[0077] The performance test method is the same as that of Example 1. The results are shown in Table 4, which shows that the main technical indicators of the prepared Portland cement clinker meet the product requirements of the strength grade of 32.5 in the national standard for general Portland cement (GB 175-2007).

[0078] Example 4:

[0079] like Figure 1 As shown, according to Figure 1 The silicate cement clinker 4 was prepared according to the process shown and the proportions in Tables 1 and 2.

[0080] The following steps are involved:

[0081] S1. Drying: dry the ferronickel slag, blast furnace slag, alumina and lime at 120°C for 2 h.

[0082] S2, mixing: the ferronickel slag leached with sulfuric acid after drying in step S1, blast furnace slag, alumina and lime are mixed in a certain proportion and then ball-milled on a planetary ball mill. The rotation speed during ball milling is set to 400 r / min, the revolution speed is 600 r / min, the grinding time is 1 h, and after ball milling, the ore is passed through a 200 mesh sieve to obtain ferronickel slag powder with a particle size of less than 74 μm.

[0083] In step S2, the material ratio is as follows: nickel iron slag sulfuric acid leaching residue is added in an amount of 28.1% of the total raw material, blast furnace slag is added in an amount of 8.2%, lime is added in an amount of 59.9%, and alumina is added in an amount of 3.8%.

[0084] S3. Briquetting: placing the raw material obtained in step S2 into a stainless steel mold and pressing it into raw material blocks at a pressure of 20 MPa.

[0085] S4, roasting: roasting the raw material blocks prepared in step S3 in a muffle furnace at a roasting temperature of 1400° C., taking them out of the furnace immediately after keeping them warm for 30 minutes, and rapidly cooling them with a fan to prepare Portland cement clinker 4.

[0086] S5. Add 7% gypsum to the Portland cement clinker 4 fired in step S4, and then fully mix it using a planetary ball mill. The rotation speed of the planetary ball mill is set to 350 r / min, the revolution speed is set to 450 r / min, and the grinding time is 2 h. After ball milling, pass it through a 200 mesh sieve to obtain Portland cement with a particle size of less than 74 μm.

[0087] The performance test method is the same as that of Example 1. The results are shown in Table 4, which indicate that the prepared Portland cement clinker meets the product requirement of strength grade 32.5 in the national standard for ordinary Portland cement (GB 175-2007).

[0088] Example 5:

[0089] like Figure 1 As shown, according to Figure 1 The silicate cement clinker 5 was prepared according to the process shown and the proportions in Tables 1 and 2.

[0090] The following steps are involved:

[0091] S1. Drying: drying the nickel-iron slag, blast furnace slag, alumina and lime at 105°C for 3 hours.

[0092] S2, mixing: the ferronickel slag leached with sulfuric acid after drying in step S1, blast furnace slag, alumina and lime are mixed in a certain proportion and then ball-milled on a planetary ball mill. The rotation speed during ball milling is set to 350 r / min, the revolution speed is 400 r / min, the grinding time is 1 h, and after ball milling, the ore is passed through a 200 mesh sieve to obtain ferronickel slag powder with a particle size of less than 74 μm.

[0093] In step S2, the material ratio is as follows: nickel-iron slag sulfuric acid leaching residue is added in an amount of 30.0% of the total raw material, blast furnace slag is added in an amount of 8.3%, lime is added in an amount of 57.8%, and alumina is added in an amount of 3.9%.

[0094] S3. Briquetting: placing the raw material obtained in step S2 into a stainless steel mold and pressing it into raw material blocks at a pressure of 15 MPa.

[0095] S4, roasting: roasting the raw material blocks prepared in step S3 in a muffle furnace at a roasting temperature of 1400° C., taking them out of the furnace immediately after keeping them warm for 60 minutes, and rapidly cooling them with a fan to prepare Portland cement clinker 5.

[0096] S5. Add 7% gypsum to the Portland cement clinker 5 fired in step S4, and then mix it thoroughly using a planetary ball mill. The rotation speed of the planetary ball mill is set to 300 r / min, the revolution speed is set to 400 r / min, and the grinding time is 1 hour. After ball milling, pass through a 200 mesh sieve to obtain Portland cement with a particle size of less than 74 μm.

[0097] The performance test method is the same as that of Example 1. The results are shown in Table 4, which indicate that the prepared Portland cement clinker meets the product requirement of strength grade 32.5 in the national standard for ordinary Portland cement (GB 175-2007).

[0098] Comparative Example 1:

[0099] like Figure 1 As shown, the contents of Comparative Example 1 are similar to those of Example 1, and the only difference is that the calcination temperature in step S4 is lower, as follows:

[0100] S1-S3 are exactly the same as in Example 1.

[0101] S4, roasting: roasting the raw material blocks prepared in step S3 in a muffle furnace at a roasting temperature of 1350° C., taking them out of the furnace immediately after keeping them warm for 60 minutes, and rapidly cooling them with a fan to prepare Portland cement clinker 6.

[0102] S5. Exactly the same as in Example 1.

[0103] After testing, the physical structure of the prepared silicate cement clinker 6 is as follows Figure 3 As shown in the curve at a temperature of 1350°C, the diffraction intensity of cement phases such as C3S and C2S is much lower than that of the samples of Example 1 and Example 2, and it can be clearly observed that the calcined product contains unreacted CaO phase, as shown in the SEM diagram. Figure 4 The EDS analysis results are shown in Table 3. There are unreacted lime and silicate cement phase precursors, which is consistent with the Figure 3This is consistent with the analysis results, indicating that the temperature of 1350℃ is too low and the cement phase is not fully developed.

[0104] Comparative Example 2:

[0105] like Figure 1 As shown, the content of Comparative Example 2 is similar to that of Example 1, except that ferronickel slag is not used in the raw material formula, but leaching residue of hydrometallurgical zinc smelting is used:

[0106] Clinker 7 prepared according to the method of Example 1:

[0107] After testing, the obtained clinker contained almost no C3S and C2S phases, and failed to produce qualified silicate cement clinker.

[0108] Comparative Example 3:

[0109] like Figure 1 As shown, Comparative Example 3 is similar to Example 1, except that blast furnace slag is not added to the raw material formula:

[0110] Prepare Portland cement clinker 8 according to the method of Example 1:

[0111] After testing, it was found that although the obtained cement clinker contained C3S, C3A and C2S phases, no calcium aluminoferrite phase was formed, and the C3S content was reduced and the C3A content was increased. The prepared cement slurry set quickly and had low strength, which did not meet the national standard requirements.

[0112] Comparative Example 4:

[0113] like Figure 1 As shown, the content of Comparative Example 4 is similar to that of Example 1, except that no alumina is added to the raw material formula:

[0114] Prepare Portland cement clinker 9 according to the method of Example 1:

[0115] After testing, it was found that although the obtained cement clinker contained C3S and C2S phases, no calcium aluminate and calcium ferroaluminate phases were formed. The prepared cement slurry set very slowly and had low strength, which did not meet the national standard requirements.

[0116] Comparative Example 5:

[0117] like Figure 1 As shown, Comparative Example 5 is similar to Example 1, except that lime is not added to the raw material formula:

[0118] Prepare Portland cement clinker 10 according to the method of Example 1:

[0119] After testing, the obtained clinker contained almost no C3S and C2S phases, and failed to produce qualified silicate cement clinker.

[0120] Comparative Example 6:

[0121] like Figure 1 As shown, the contents of Comparative Example 6 are similar to those of Example 1, and the only difference is that the raw material ratios used in the raw material formula are different, specifically:

[0122] In step S2, the material ratio is as follows: the amount of nickel-iron slag sulfuric acid leaching residue added is 33% of the total raw material amount, the amount of Fe2O3 added is 7%, the amount of CaO added is 50%, and the amount of Al2O3 added is 6%.

[0123] Prepare Portland cement clinker 11 according to the method of Example 1:

[0124] After testing, it was found that although the obtained clinker contained C3S, C2S, C3A and calcium aluminoferrite cement phase, the prepared silicate cement slurry had a fast initial setting time and a low compressive strength value, which did not meet the national standard requirements for silicate cement clinker.

[0125] The EDS analysis results of the cement clinker in Examples 1-2 and Comparative Example 1 are summarized in Table 3. As shown in Table 3, points 1, 2, and 3 are Figure 4 , Figure 5 , Figure 6 Points 1, 2, and 3 in the chart.

[0126] Table 3 EDS analysis results

[0127]

[0128] The f-CaO content in the clinker was determined using the glycerol method specified in the national standard (GB / T176-2017). The standard consistency water requirement, initial setting time, final setting time, and stability of the cement paste were tested according to the national standard (GB / T 1346-2001). The strength of the cement mortar was tested according to the national standard (GB / T 17671-1999). The test results, shown in Table 4, indicate that the main technical indicators do not meet the requirements of the national standard for general-purpose Portland cement (GB 175-2007).

[0129] The main properties of the cement clinkers in Examples 1-5 and Comparative Examples 1-6 are summarized in Table 4.

[0130] Table 4 Main properties of cement clinker prepared according to the above examples and comparative examples

[0131]

[0132]

[0133] Note: Since comparative example 2 has almost no hydraulic properties, there is no cement performance parameter value, which is represented by “-”.

[0134] In summary, the present invention discloses a method for preparing general-purpose Portland cement clinker using ferronickel slag leaching residue, which relates to the fields of environmental protection and building materials. The method comprises: first, mixing ferronickel slag sulfuric acid leaching residue with blast furnace slag, lime, and a regulator, ball milling the mixture, and then calcining the mixture at high temperature; then rapidly cooling the calcined product; and finally grinding the mixture to produce Portland cement clinker. The present invention uses a high-temperature multiphase reaction to convert the raw material into a cement phase containing active components such as tricalcium silicate, dicalcium silicate, and tetracalcium aluminoferrite. The ferronickel slag sulfuric acid leaching residue has a very small particle size and does not require grinding. The slag can be added in large quantities and is easy to burn through. The main performance indicators of the produced Portland cement clinker meet the national standard requirements for general-purpose Portland cement clinker. The present invention has important reference value for the reduction of ferronickel slag and has excellent market prospects and promotion value.

[0135] At this point, those skilled in the art will recognize that, although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. A method for preparing general Portland cement clinker using ferronickel slag leaching residue, characterized in that: The method comprises the following steps: Step S1: Drying: drying the nickel-iron slag sulfuric acid leaching residue, Fe2O3, alumina Al2O3 and lime CaO at a certain temperature; Step S2: ball milling: the nickel-iron slag sulfuric acid leaching residue obtained after drying in step S1, Fe2O3, alumina Al2O3 and lime CaO are mixed in a certain proportion and then ball milled for a certain time, and sieved after ball milling to obtain raw material powder; Step S3: Briquetting: placing the raw material powder obtained in step S2 into a steel mold and pressing it into raw material blocks; Step S4: calcining: calcining the raw material blocks prepared in step S3, taking them out immediately after calcination and keeping them warm, and rapidly cooling them to prepare Portland cement clinker; Step S5: Gypsum is added to the Portland cement clinker fired in step S4, and then ball-milled to mix thoroughly. After ball-milling, the mixture is sieved to obtain universal Portland cement; In the step S1, the nickel-iron slag sulfuric acid leaching residue, Fe2O3, alumina Al2O3 and lime CaO are dried at 100-120°C for 2-6 hours respectively; In step S2, the mass of the nickel-iron slag sulfuric acid leaching residue added is 25-30% of the total amount of the raw material powder, the amount of Fe2O3 added is 2-5% of the total amount of the raw material powder, the amount of CaO added is 55-65% of the total amount of the raw material powder, and the amount of Al2O3 added is 4-10% of the total amount of the raw material powder; the ball mill is a planetary ball mill; the rotation speed during ball milling is set to 250-400 r / min, the revolution speed is 400-600 r / min, the grinding time is 1-4 h, and after ball milling, the ore is sieved with a 200-mesh sieve; the mass of the sieve residue does not exceed 2% of the mass of the raw material before sieving; the particle size of the raw material powder is less than 74 μm; In step S4, the calcination is carried out in a muffle furnace; the calcination temperature is 1400-1450° C.; the calcination is kept warm for 30-120 minutes; and the calcination is rapidly cooled by air cooling or other methods.

2. A method for preparing general Portland cement clinker by utilizing ferronickel slag leaching residue as described in claim 1, characterized in that: The pressure for pressing the raw material block in step S3 is 10-30 MPa.

3. A method for preparing general Portland cement clinker by utilizing ferronickel slag leaching residue as described in claim 1, characterized in that: The mass ratio of gypsum added in step S5 is 3-7% of the silicate cement clinker; the ball mill is a planetary ball mill; the rotation speed during ball milling is set to 250-350 r / min, the revolution speed is 400-500 r / min, the grinding time is 1-3 hours, and after ball milling, the ore is sieved through a 200-mesh sieve, and the mass of the residue does not exceed 2% of the mass of the raw material before sieving; the particle size of the general silicate cement is less than 74 μm.

4. A method for preparing general Portland cement clinker by utilizing ferronickel slag leaching residue as described in claim 1, characterized in that, The Fe2O3 is one or more of common Fe2O3 chemical reagent, blast furnace slag, steelmaking slag, ferroalloy smelting slag, and rust.

5. A method for preparing general Portland cement clinker using ferronickel slag leaching residue as described in claim 1, characterized in that: The lime CaO is one or more of common CaO chemical reagent, limestone, lime, high calcium tailings, and smelting slag.

6. A method for preparing general Portland cement clinker using ferronickel slag leaching residue as described in claim 1, characterized in that: The Al2O3 is one or more of common Al2O3 chemical reagent, fly ash, and bauxite.

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