A method for preparing calcium iron garnet-based microcrystalline glass by using iron-carbon-sulfur waste residue

Abstract

The application discloses a method for preparing calcium iron garnet-based glass ceramics by using iron-carbon-sulfur waste residues, and belongs to the field of iron-carbon-sulfur waste residue building material utilization. The iron-carbon-sulfur waste residues are subjected to raw material modification design, weighing, mixing, and restricted melting to form modified base materials. The modified base materials are subjected to crushing, screening, forming, graded heat treatment sintering, and annealing to obtain a series of iron-based crystallization samples. The crystalline phase formation and crystalline phase evolution rules of the iron-containing components in the waste residues are explored, and the glass ceramics with controllable crystalline phase types, morphologies and sizes are obtained. The calcium iron garnet-based glass ceramics are obtained by high-temperature modification of the iron-carbon-sulfur waste residues and fine regulation and control of the graded heat treatment of the modified base material crystallization temperature, the high-value glass ceramic utilization goal of the iron-carbon-sulfur waste residues is achieved, the melting energy consumption is greatly reduced, the problems of melt overflow, early crystallization and porosity easily occurring in the iron-based system are avoided, and the cost is saved and the process safety is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of smelting slag resource utilization, and in particular relates to a method for high-value glass-ceramization of waste slag, and especially relates to a method for preparing calcium iron garnet-based glass-ceramics using iron-carbon-sulfur waste slag. BACKGROUND

[0002] Iron-carbon-sulfur waste slag is a mixture of waste slag containing iron, carbon and sulfur elements discharged in the process of metal smelting. The sources of iron, carbon and sulfur elements are different, for example, the iron ore and fly ash added in the process of lead-zinc smelting promote the discharge of waste slag containing iron and carbon elements, and the zinc sulfide phase in zinc ore will make the waste slag contain mixed sulfur elements. According to statistics, the historical reserves of iron-carbon-sulfur waste slag exceed 200 million tons. In addition to the conventional components such as CaO, FeO x , SiO2, Al2O3, MgO, etc., the iron-carbon-sulfur waste slag also contains trace amounts of heavy metals such as Pd, Cd, Cr, etc. The large storage of these waste slags not only wastes land resources, but also brings great risks to the environment due to the leaching of heavy metals.

[0003] Waste slag building materialization is a mature and widely used waste slag resource utilization technology, including the preparation of cement, concrete, ceramics, etc. from waste slag, and the glass-ceramic technology is a relatively new technology for waste slag building materialization. The development of this technology not only helps to convert harmful waste slag into high-value glass-ceramics, but also helps to effectively solidify heavy metals in the form of crystal and glass in the waste slag. In the past, tailings, blast furnace slag, steel slag, silica slag, fly ash and other solid wastes were used to prepare CaO-Al2O3-SiO2(CAS) and CaO-MgO-Al2O3-SiO2(CMAS) system glass-ceramics. CN112340988A discloses a preparation method of CMAS system glass-ceramics based on TiO2 in titanium-containing blast furnace slag as nucleating agent. The TiO2 in the blast furnace slag itself is used as a nucleating agent to reduce the disposal cost of titanium-containing blast furnace slag in the steel industry. CN110845144A discloses a method for glass-ceramization of iron-trapping waste catalyst smelting slag. The heavy metals Fe2O3, Cr2O3, TiO2, NiO, PbO, etc. in the smelting slag are used as nucleating agents, and the glass-ceramics obtained after casting, calendering and crystallization can solidify the heavy metals in the smelting slag, avoiding pollution.

[0004] Table 1 Preparation method of part of silicon-iron alloy

[0005]

[0006]

[0007] In contrast, there are few reports on iron-carbon-sulfur waste residue-based glass-ceramics with CaO-Fe2O3-SiO2(CFS) components. One key reason is that iron-carbon-sulfur waste residue contains a large amount of FeO x , C and S components, which easily causes serious overflow of waste residue melt at high temperature and premature crystallization of glass, and makes the prepared glass-ceramics have a large number of pores, resulting in poor physical and mechanical properties of the obtained glass-ceramics. In order to solve the problem of FeO x , smelting reduction method, ferrosilicon alloy preparation method and other methods are developed to reduce the iron content in the waste residue, and secondary waste residue is formed to prepare glass-ceramics (Table 1). However, this method requires an additional melting step (working temperature such as 1450℃-1500℃) to reduce the FeO x component in the waste residue to metallic iron or form ferrosilicon alloy. In addition, the remaining residue after iron selection also needs to be subjected to secondary high-temperature melting and conditioning to prepare the microcrystalline glass after re-proportioning. Although this method can obtain additional pig iron or ferrosilicon alloy, the additional melting and iron selection operation not only complicates the process flow, but also greatly increases the melting energy consumption and process cost required for preparing CFS-based glass-ceramics.

[0008] In summary, how to develop a short process and low energy consumption method for preparing low-porosity glass-ceramics using iron-carbon-sulfur waste residue has become an urgent problem for technical personnel in the field. SUMMARY

[0009] The purpose of the present application is to provide

[0010] 1. In order to solve the above technical problems, the present application provides a method for preparing andyroborate-based glass-ceramics using iron-carbon-sulfur waste residue, which has a short preparation process, low energy consumption and is easy to be used in large scale for preparing low-porosity glass-ceramics from iron-carbon-sulfur waste residue. In order to achieve the purpose of the present application, the following technical solution is adopted (Table 2):

[0011] Table 2 Preparation method of the present patent glass-ceramics

[0012]

[0013]

[0014] S1. The present application provides a method for preparing andyroborate-based glass-ceramics using iron-carbon-sulfur waste residue, which comprises the following steps:

[0015] (1) modifying and designing the iron-carbon-sulfur waste residue to obtain a modified waste residue precursor;

[0016] (2) pretreating and limiting the modified waste residue precursor obtained in step (1) to melt and quench, to obtain a modified base material;

[0017] (3) the modified base material obtained in step (2) is first sintered to obtain a base material green body, and then the green body is subjected to multi-step graded heat treatment to obtain a series of sintered samples including calcium-iron garnet-based glass-ceramics.

[0018] In order to overcome the influence of iron-carbon-sulfur components in the iron-carbon-sulfur waste residue on the process, obtain a short process, and focus on the preparation of glass-ceramics by waste residue modification and crystallization kinetics control, the temperature-induced phase change and morphology evolution of the iron-rich component in the alkaline glass, and the influence of the FeOx component on the structure and performance of the glass-ceramics are studied. The process not only solves the problem of easy overflow of high-temperature melt caused by high FeOx components in the waste residue, reduces the safety hidden danger brought by large-scale production, avoids the possibility of premature crystallization of the base glass caused by the iron component in the waste residue, and eliminates the adverse effects of residual carbon and sulfides in the waste residue on the structure and performance of the glass-ceramics, which is beneficial to obtain high-quality iron-rich glass-ceramics.

[0019] Preferably, the modification design in step (1) is mainly based on the requirements of the CFS glass system, and the modified waste residue precursor raw materials are weighed according to the formula, including iron-carbon-sulfur waste residue and modified auxiliary materials, and the mass percentages are 70-90:10-30 respectively, and the sum of the mass percentages of the iron-carbon-sulfur waste residue and the modified auxiliary materials is 100%.

[0020] The modified auxiliary materials in the application mainly include lead tailings, sodium carbonate, barium carbonate and fining agents, and the mass ratio is 10-20:2-8:2-4:0.1-5.

[0021] Preferably, the lead tailings include components SiO2, Al2O3, Fe2O3, and the weight ratio is 55-70:8-20:3-8; the lead tailings also include three or at least four of the components CaO, Na2O, K2O, MgO, ZnO, TiO2 and CuO, and the proportion of CaO, Na2O, K2O, MgO, ZnO, TiO2 and CuO in the lead tailings is independently 0-5wt%, but not including 0.

[0022] The fining agent includes one or two of CeO2, Sb2O3, NaSbO3 and NaNO3, and the proportion of CeO2, Sb2O3, NaSbO3 and NaNO3 in the modified waste residue precursor raw materials is independently 0.1-5wt%.

[0023] Preferably, the iron-carbon-sulfur waste residue in step (1) comprises SiO2, Fe2O3, CaO, C, Al2O3, ZnO, MnO, CuO, Na2O, MgO and SO3, and the weight ratio of each component is 20-35:15-35:10-20:1-3:3-5:2-4:0.4-4:2-5:0.6-2:0.5-2:0.9-3;

[0024] In this invention, the pretreatment in step (2) includes drying, ball milling, and multi-stage sieving of the modified waste residue precursor;

[0025] Preferably, the drying temperature in step (2) is 120-160℃; the ball milling speed is 350-450rpm; the multi-stage screening includes first removing large pieces of rust impurities by using a sieve-type method, and then fully ball milling the obtained modified waste residue precursor and then screening it a second time; the screening particle size is 180-200 mesh.

[0026] In this invention, the restricted heat treatment melting in step (2) is mainly carried out in a box furnace;

[0027] Preferably, the limiting heat treatment temperature in step (2) is 1420-1450℃;

[0028] Preferably, the limiting heat treatment heating rate in step (2) is 8-10℃ / min in the 30-300℃ range; 3-5℃ / min in the 300-600℃ range; and 6-8℃ / min in the 600-1450℃ range.

[0029] Preferably, the heat preservation time in the 300-600℃ temperature range in step (2) is 0.2-0.5h, and the heat preservation time in the 1420-1450℃ temperature range is 1-2.5h;

[0030] Preferably, the exhaust gas recovery in step (2) is a CO2 / SO4 process. x Exhaust gas recovery device;

[0031] Preferably, the temperature of the water in the water quenching step (2) is 15-30℃.

[0032] In this invention, the sintering pretreatment in step (3) includes filtering, drying, ball milling, and sieving the modified base material; the drying temperature is 120-160℃; the ball milling speed is 350-450rpm; and the sieving particle size is 180-200 mesh.

[0033] Preferably, the multi-step graded heat treatment in step (3) is a sintering and crystallization treatment of the base material green body. Based on the thermal analysis curve, 11 graded temperature heat treatment conditions are set, namely 130-160℃ / 1-2.5h, 400-500℃ / 1-2.5h, 550-600℃ / 1-2.5h, 650-750℃ / 1-2.5h, 780-810℃ / 1-2.5h, 850-900℃ / 1-2.5h, 1000-1020℃ / 1-2.5h, 1040-1060℃ / 1-2.5h, 1080-1110℃ / 1-2.5h, 1130-1160℃ / 1-2.5h and 1180-1200℃ / 1-2.5h.

[0034] In this invention, the 11 temperature heat treatments in step (3) are carried out in a KSL1200 crystallization furnace;

[0035] Preferably, the modified base material described in step (3) is subjected to multi-stage sieving before heat treatment to obtain a 180-200 mesh modified base material;

[0036] Preferably, the heating rate of the 11 temperature gradient heat treatments in step (3) is 5-8℃ / min at 30-500℃; 1-3℃ / min at 500-750℃; and 4-6℃ / min at 750-1200℃.

[0037] S2. A preferred embodiment of the present invention, wherein the method comprises the following steps:

[0038] (1) Weigh the modified waste residue precursor raw materials according to the formula, including iron-carbon-sulfur waste residue, lead tailings, sodium carbonate, barium carbonate and clarifying agent, with their mass percentages being 70-90:10-20:2-8:2-4:0.1-5, and the sum of the mass percentages of the modified waste residue precursor raw materials is 100%.

[0039] The iron-carbon-sulfur waste residue includes the components SiO2, Fe2O3, CaO, C, Al2O3, ZnO, MnO, CuO, Na2O, MgO, and SO3, with the following weight ratio: 20-35:15-35:10-20:1-3:3-5:2-4:0.4-4:2-5:0.6-2:0.5-2:0.9-3.

[0040] The lead tailings comprises SiO2, Al2O3, and Fe2O3 in a weight ratio of 55-70:8-20:3-8; the lead tailings also comprises three or at least four of the following components: CaO, Na2O, K2O, MgO, ZnO, TiO2, and CuO, with each component accounting for 0-5 wt% of the lead tailings, but excluding 0.

[0041] The clarifying agent includes one or a combination of at least two of CeO2, Sb2O3, NaSbO3, and NaNO3, and the proportions of CeO2, Sb2O3, NaSbO3, and NaNO3 in the modified waste residue precursor raw material are each 0.1-5 wt%, but do not include 0.

[0042] (2) The modified waste residue precursor raw material obtained in step (1) is dried, ball-milled, and screened in multiple stages; the drying temperature is 120-160℃; the ball milling speed is 350-450rpm; the multi-stage screening includes first removing large rust impurities by using a double sieve method, and then fully ball-milling the obtained modified waste residue precursor and screening it again; the screening particle size is 180-200 mesh.

[0043] (3) The modified waste residue precursor raw material obtained after step (2) is subjected to restricted heat treatment and melted in a box furnace, and then water quenched to obtain the modified base material; the heat treatment temperature is 1420-1450℃; the restricted heat treatment heating rate is 8-10℃ / min in the 30-300℃ range, 3-5℃ / min in the 300-600℃ range, and 6-8℃ / min in the 600-1450℃ range; the holding time in the 300-600℃ range is 0.2-0.5h, and the holding time in the 1420-1450℃ range is 1-2.5h; the water temperature used for water quenching is 15-30℃.

[0044] (4) The modified base material obtained in step (3) is filtered, dried, ball-milled, multi-stage sieved, and molded to form a base material green body; the drying temperature is 120-160℃; the ball milling speed is 350-450rpm; the sieve particle size is 180-200 mesh;

[0045] (5) The base material green body obtained in step (4) is subjected to multi-step graded heat treatment to obtain a series of sintered crystallized samples. According to the thermal analysis curve (DTA), 11 graded temperature heat treatment conditions are set, such as 130-160℃ / 1-2.5h, 400-500℃ / 1-2.5h, 550-600℃ / 1-2.5h, 650-750℃ / 1-2.5h, 780-810℃ / 1-2.5h, 850-900℃ / 1-2.5h, 1000-1020℃ / 1-2.5h, 1040-1060℃ / 1-2.5h, 1080-1110℃ / 1-2.5h, 1130-1160℃ / 1-2.5h or 1180-1200℃ / 1-2.5h;

[0046] The heating rate for the 11 graded temperature heat treatments was controlled at 5-8℃ / min for temperatures ranging from 30-500℃; 1-3℃ / min for temperatures ranging from 500-750℃; and 4-6℃ / min for temperatures ranging from 750-1200℃. After graded heat treatment, a series of sintered crystallized samples containing calcium iron garnet-based microcrystalline glass were obtained from the base material green body.

[0047] S3. The present invention provides a microcrystalline glass prepared using the method described in the first aspect.

[0048] In this invention, the main crystalline phases of the microcrystalline glass are andradite and hematite, and the secondary crystalline phases are diopside and anorthosite, with a bulk density of 2.65-2.79 g / cm³. 3 Flexural strength 75-126MPa, compressive strength 625-890MPa, Mohs hardness 6-7, acid resistance 0.1-0.2%, alkali resistance 0.01-0.05%, water absorption 0.01-0.06%.

[0049] S4. The present invention provides an application of microcrystalline glass as described in S2 in the fields of construction, metallurgy, machinery and chemical industry.

[0050] The principle of this invention is as follows:

[0051] Based on the CaO-Fe2O3-SiO2 ternary phase diagram, andradite and hematite crystal phases can be formed according to the composition of iron-carbon-sulfur waste residue. Glass networks often contain three components: SiO2 / Al2O3, CaO / MgO, and Na2O / K2O. SiO2 / Al2O3 is the glass network forging body, Na2O / K2O is the glass network modifier or alterer, and CaO / MgO is the glass network intermediate. The main component of the modified base material, SiO2 / Fe2O3, and a small amount of Al2O3 are used as the glass forging body. To adjust the process properties of the melt and meet crystallization requirements, adjusting oxides Na2O and BaO, as well as lead tailings and clarifying agents, are added to the iron-carbon-sulfur waste residue. Na2O mainly reduces the degree of polymerization and thermal stability of the glass network by forming sodium-oxygen ionic bonds, thereby enhancing the glass's crystallization ability. In addition, in this invention, glass crystallization mainly relies on the surface energy of a large number of particles in the modified base material to nucleate and crystallize, so that the particles have a certain creep during the crystallization process to help the particles achieve adhesion and sintering.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) This invention uses iron-carbon-sulfur waste residue as the main raw material to prepare microcrystalline glass, realizing the high-value utilization of iron-carbon-sulfur waste residue and effectively alleviating the increasing land occupation and environmental pollution problems caused by iron-carbon-sulfur waste residue.

[0054] (2) Based on the component characteristics of the CFS system and through the design of waste residue modification, this invention uses modifying reagents and clarifying agents as auxiliary raw materials for the preparation of iron-based microcrystalline glass, eliminating the need for melting, high-temperature reduction, cooling, crushing and magnetic separation processes required for iron selection before the preparation of microcrystalline glass in traditional processes. It has the advantages of simple steps, low energy consumption and low cost; at the same time, it avoids dust pollution containing trace heavy metals caused by the magnetic separation process.

[0055] (3) In the melting stage of the modified waste residue precursor and the sintering and crystallization stage of the modified base material, the present invention adopts a limited heat treatment measure of controlling the heating rate in a temperature zone, which avoids the adverse effects of iron elements in iron-carbon-sulfur waste residue on the melting and crystallization process to the greatest extent; at the same time, it eliminates the possibility that carbon and sulfides will aggravate the melt overflow due to high temperature gas production and aggravate the porosity problem of microcrystalline glass samples, which is conducive to obtaining high-quality microcrystalline glass.

[0056] (4) This invention prepared a series of sintered samples with different main crystal phases and differential sintering shrinkage rates at different temperatures through restrictive heat treatment measures. The crystal phase evolution process of iron-containing components in waste residue under 11 heat treatment conditions was studied. Controllable preparation conditions of microcrystalline glass containing rare ferrogarnet main crystal phase were obtained, which expanded the path for high-value microcrystalline glass utilization of iron-carbon-sulfur waste residue. In addition, the evolution law of these iron-containing crystal phases can provide a reference for the future application of iron-carbon-sulfur waste residue in the field of magnetism.

[0057] (5) The main crystalline phases of the microcrystalline glass prepared in this invention are andradite and hematite, and the secondary crystalline phases are diopside and anorthosite, with a maximum bulk density of 2.79 g / cm³. 3 The resulting microcrystalline glass exhibits a maximum flexural strength of 126 MPa, a maximum compressive strength of 890 MPa, a maximum Mohs hardness of 7, a minimum acid resistance of 0.1%, a minimum alkali resistance of 0.01%, and a minimum water absorption of 0.01%. It possesses high mechanical strength and excellent corrosion resistance, making it a promising candidate for applications in construction, metallurgy, machinery, and chemical industries. Attached Figure Description

[0058] Figure 1 This is a process flow diagram of preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue provided by the present invention;

[0059] Figure 2 This is the PXRD pattern of the modified base material obtained in Example 1;

[0060] Figure 3 This is the DTA diagram of the base material green body obtained in Example 2;

[0061] Figure 4 These are PXRD images of samples obtained after heating the modified base materials of Examples 1-11 at different temperatures;

[0062] Figure 5 These are microscopic morphology images of samples sintered under the temperature conditions of Comparative Examples 6, 7, 2, and 8.

[0063] Figure 6 This is a diagram of the high-temperature melt overflow obtained in Example 3;

[0064] Figure 7 This is a diagram of the calcium iron garnet-based microcrystalline glass obtained in Example 2;

[0065] Figure 8 This is a sample image with high porosity obtained in Example 3. Detailed Implementation

[0066] To better explain the present invention, the following embodiments are provided to further illustrate the content of the present invention, but the present invention is not limited to the following embodiments.

[0067] Example 1

[0068] This invention provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue, such as... Figure 1 The method includes the following steps:

[0069] (1) Weigh the modified waste residue precursor raw materials according to the formula, including iron-carbon-sulfur waste residue, lead tailings, sodium carbonate, barium carbonate and clarifying agent, with a mass percentage of 70:20:6:2:2, and the sum of the mass percentages of the modified waste residue precursor raw materials is 100%.

[0070] The iron-carbon-sulfur waste residue includes the components SiO2, Fe2O3, CaO, C, Al2O3, ZnO, MnO, CuO, Na2O, MgO and SO3, with a weight ratio of 33:31:18:3:4:3:0.4:2:1:0.6:3.

[0071] The lead tailings comprises SiO2, Al2O3, Fe2O3, CaO, Na2O, K2O, MgO, ZnO, TiO2, and CuO, with a weight ratio of 64:16:7:3:1:3:0.8:0.5:0.3:2.

[0072] The clarifying agent comprises CeO2 and NaSbO3, with a weight ratio of 2:5.

[0073] (2) The modified waste residue precursor raw material obtained in step (1) is dried, ball-milled, and screened in multiple stages; the drying temperature is 140℃; the ball milling speed is 350rpm; the multi-stage screening includes first removing large pieces of rust impurities by using a double sieve method, and then fully ball-milling the obtained modified waste residue precursor and screening it again; the screening particle size is 180 mesh.

[0074] (3) The modified waste residue precursor raw material obtained after step (2) is subjected to restricted heat treatment and melted in a box furnace, and then water quenched to obtain the modified base material; the heat treatment temperature is 1450℃; the restricted heat treatment heating rate is 8℃ / min in the 30-300℃ range, 5℃ / min in the 300-600℃ range, and 8℃ / min in the 600-1450℃ range; the holding time in the 450℃ temperature zone is set separately for 0.2h, and the holding time in the 1430℃ temperature zone is set for 1h; the water temperature used for water quenching is 20℃.

[0075] (4) The modified base material obtained in step (3) is filtered, dried, ball-milled, multi-stage sieved, and molded to form a base material green body; the drying temperature is 160℃; the ball milling speed is 350rpm; and the sieve particle size is 200 mesh.

[0076] (5) The base material green body obtained in step (4) is subjected to multi-step graded heat treatment to obtain a series of sintered crystallized samples. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions implemented in this embodiment are a heating temperature of 1050℃, a heating rate of 5℃ / min, and a crystallization time of 1h. The base material green body is then heat-treated to obtain sintered crystallized samples.

[0077] Example 2

[0078] This invention provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue, such as... Figure 1 The method includes the following steps:

[0079] (1) Weigh the modified waste residue precursor raw materials according to the formula, including iron-carbon-sulfur waste residue, lead tailings, sodium carbonate, barium carbonate and clarifying agent, with a mass percentage of 80:10:5:3:2, and the sum of the mass percentages of the modified waste residue precursor raw materials is 100%.

[0080] The iron-carbon-sulfur waste residue includes the components SiO2, Fe2O3, CaO, C, Al2O3, ZnO, MnO, CuO, Na2O, MgO and SO3, with a weight ratio of 29:35:20:1:3:2:0.6:3:0.6:2:0.9.

[0081] The lead tailings comprises SiO2, Al2O3, Fe2O3, CaO, Na2O, K2O, MgO, ZnO, TiO2, and CuO, with a weight ratio of 65:15:6:4:2:2:1:0.3:0.5:2.

[0082] The clarifying agent comprises CeO2 and NaNO3, with a weight ratio of 1:2.

[0083] (2) The modified waste residue precursor raw material obtained in step (1) is dried, ball-milled, and screened in multiple stages; the drying temperature is 150℃; the ball milling speed is 400rpm; the multi-stage screening includes first removing large pieces of rust impurities by using a double sieve method, and then fully ball-milling the obtained modified waste residue precursor and then screening it again; the screening particle size is 180 mesh.

[0084] (3) The modified waste residue precursor raw material obtained after step (2) is subjected to restricted heat treatment and melted in a box furnace, and then water quenched to obtain the modified base material; the heat treatment temperature is 1450℃; the restricted heat treatment heating rate is 8℃ / min in the range of 30-300℃, 3℃ / min at 450℃, and 5℃ / min in the range of 600-1450℃; the holding time in the 450℃ temperature zone is set separately for 0.5h, and the holding time in the 1450℃ temperature zone is set for 2h; the water temperature used for water quenching is 20℃.

[0085] (4) The modified base material obtained in step (3) is filtered, dried, ball-milled, multi-stage sieved, and molded to form a base material green body; the drying temperature is 160℃; the ball milling speed is 350rpm; and the sieve particle size is 200 mesh.

[0086] (5) The base material green body obtained in step (4) is subjected to multi-step graded heat treatment to obtain a series of sintered crystallized samples. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions implemented in this embodiment are a heating temperature of 1050℃, a heating rate of 5℃ / min, and a crystallization time of 1.2h. After heat treatment, the base material green body yields 8 sintered crystallized samples. Figure 7 ).

[0087] Figure 2 The PXRD pattern of the modified base material obtained in step (3) of this embodiment is shown below. Figure 2 It can be seen that the modified waste residue precursor raw material has been completely melted to form a homogeneous glass phase. Figure 3 This is the DTA diagram of the base material green body obtained in step (5) of this embodiment. Figure 3 It can be seen that the base material green billet has obvious exothermic crystallization peaks at 752℃, 835℃ and 1104℃ respectively. Figure 7 This is an optical image of the hellite-based microcrystalline glass obtained in step (5) of this embodiment. Figure 7 It can be seen that the surface of the sample obtained after the modified waste residue is melted and crystallized by restricted heat treatment has no obvious porosity.

[0088] Example 3

[0089] This invention provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue, such as... Figure 1 The method includes the following steps:

[0090] (1) Weigh the modified waste residue precursor raw materials according to the formula, including iron-carbon-sulfur waste residue, lead tailings, sodium carbonate, barium carbonate and clarifying agent, with a mass percentage of 80:10:6:3:1, and the sum of the mass percentages of the modified waste residue precursor raw materials is 100%.

[0091] The iron-carbon-sulfur waste residue includes the components SiO2, Fe2O3, CaO, C, Al2O3, ZnO, MnO, CuO, Na2O, MgO and SO3, with a weight ratio of 22:33:20:3:5:2:4:5:2:0.5:1.

[0092] The lead tailings comprises SiO2, Al2O3, Fe2O3, CaO, Na2O, K2O, MgO, ZnO, TiO2, and CuO, with a weight ratio of 65:14:5:5:1:3:1:0.3:0.4:1.

[0093] The clarifying agent includes CeO2, Sb2O3 and NaSbO3, with a weight ratio of 1:2:1.

[0094] (2) The modified waste residue precursor obtained in step (1) is dried, ball-milled, and screened in multiple stages; the drying temperature is 120℃; the ball milling speed is 350rpm; the multiple stages of screening include first removing large pieces of rust impurities by using a double sieve method, and then fully ball-milling the obtained modified waste residue precursor and then screening it again; the screening particle size is 180 mesh.

[0095] (3) The modified waste residue precursor raw material obtained after step (2) is subjected to restricted heat treatment and melting in a box furnace, and then water quenched to obtain the modified base material; the heat treatment temperature is 1450℃; the entire heating process maintains a constant heating rate of 8℃ / min, and the holding time at 1450℃ is 2h; the water temperature used for water quenching is 20℃.

[0096] (4) The modified base material obtained in step (3) is filtered, dried, ball-milled, multi-stage sieved, and molded to form a base material green body; the drying temperature is 160℃; the ball milling speed is 350rpm; and the sieve particle size is 200 mesh.

[0097] (5) The base material green body obtained in step (4) is subjected to multi-step graded heat treatment to obtain a series of sintered crystallized samples. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions implemented in this embodiment are a heating temperature of 1050℃, a heating rate of 5℃ / min, and a crystallization time of 2h. Sintered crystallized samples are obtained after heat treatment of the base material green body. Figure 8 ).

[0098] Figure 6 The fused optical image obtained in step (3) of this embodiment is derived from... Figure 6 It is evident that there is significant overflow during the unrestricted heat treatment melting process of the modified waste residue, which introduces unsafe factors into the experiment. Figure 8 This is an optical image of the sintered sample obtained in step (5) of this embodiment. Figure 6 It can be seen that the sample obtained after the non-restricted molten base material is sintered and crystallized has obvious porosity on its surface.

[0099] Comparative Example 1

[0100] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 are 150℃ / 1.2h, and the resulting sintered sample is numbered Sample 1.

[0101] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystalline phases 3.

[0102] Comparative Example 2

[0103] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 450℃ / 1.2h, and the resulting sintered sample was designated as Sample 2.

[0104] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0105] Comparative Example 3

[0106] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 600℃ / 1.2h, and the resulting sintered sample was numbered Sample 3.

[0107] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystalline phases 3.

[0108] Comparative Example 4

[0109] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 745℃ / 1.2h, and the resulting sintered sample was numbered Sample 4.

[0110] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0111] Comparative Example 5

[0112] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 807℃ / 1.2h, and the resulting sintered sample was numbered Sample 5.

[0113] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0114] Comparative Example 6

[0115] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 880℃ / 1.2h, and the resulting sintered sample was numbered Sample 6.

[0116] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0117] Comparative Example 7

[0118] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 are 1010℃ / 1.2h, and the resulting sintered sample is numbered Sample 7.

[0119] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0120] Comparative Example 8

[0121] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 1100℃ / 1.2h, and the resulting sintered sample was numbered Sample 9.

[0122] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0123] Comparative Example 9

[0124] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 1150℃ / 1.2h, and the resulting sintered sample was numbered Sample 10.

[0125] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0126] Comparative Example 10

[0127] This comparative example provides a method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue. The steps are the same as in Example 2 of this invention, except that the conditions for the sintering and crystallization treatment of the basic green material are different; otherwise, they are the same as in Example 2. Based on the 11-step temperature heat treatment conditions set according to the thermal analysis curve, the heat treatment conditions of Comparative Example 1 were 1200℃ / 1.2h, and the resulting sintered sample was numbered Sample 11.

[0128] The PXRD of the sample obtained in this embodiment is shown in [reference needed]. Figure 4 List of its main crystal phases 3.

[0129] Table 3

[0130]

[0131]

[0132] The results of comparative examples 1 to 10 show that the sample obtained under the heat treatment conditions in Example 2 had the largest shrinkage rate, and the obtained sample was a gamma-iron garnet-based microcrystalline glass. Table 3 shows that with increasing sintering and crystallization temperature, the shrinkage of the sample first increased and then decreased.

[0133] In summary, this invention uses iron-carbon-sulfur waste residue as the main raw material to prepare microcrystalline glass, realizing the high-value utilization of iron-carbon-sulfur waste residue and effectively alleviating the increasing land occupation and environmental pollution problems caused by iron-carbon-sulfur waste residue. Based on the component characteristics of the CFS system and through waste residue modification design, this invention uses modifying reagents and clarifying agents as auxiliary raw materials for the preparation of iron-based microcrystalline glass, avoiding the melting, high-temperature reduction, cooling, crushing, and magnetic separation processes required for iron selection before preparing microcrystalline glass in traditional processes. It has the advantages of simple steps, low energy consumption, and low cost; at the same time, it avoids dust pollution containing trace heavy metals caused by the magnetic separation process. This invention employs a restricted heat treatment method with temperature-zoned control of heating rate during both the melting stage of the modified waste residue precursor and the sintering and crystallization stage of the modified base material. This minimizes the adverse effects of iron elements in the iron-carbon-sulfur waste residue on the melting and crystallization processes. Simultaneously, it eliminates the possibility of increased melt overflow due to high-temperature gas generation from carbon and sulfides, and avoids aggravating the porosity of the microcrystalline glass samples, thus facilitating the acquisition of high-quality microcrystalline glass. Through this restricted heat treatment method, this invention prepared a series of sintered samples with different main crystalline phases and differential sintering shrinkage rates at different temperatures, obtaining controllable preparation conditions for microcrystalline glass containing the hematite main crystalline phase, thus expanding the pathway for high-value microcrystalline glass utilization of iron-carbon-sulfur waste residue. The main crystalline phases of the microcrystalline glass prepared by this invention are hematite and hematite, and the secondary crystalline phases are diopside and anorthite, with a maximum bulk density of 2.79 g / cm³. 3 The resulting microcrystalline glass exhibits a maximum flexural strength of 126 MPa, a maximum compressive strength of 890 MPa, a maximum Mohs hardness of 7, a minimum acid resistance of 0.1%, a minimum alkali resistance of 0.01%, and a minimum water absorption of 0.01%. It possesses high mechanical strength and excellent corrosion resistance, making it a promising candidate for applications in construction, metallurgy, machinery, and chemical industries.

Claims

1. A method for preparing calcium iron garnet-based microcrystalline glass using iron-carbon-sulfur waste residue, characterized in that, Includes the following steps: (1) Modify the iron-carbon-sulfur waste residue to obtain a modified waste residue precursor; the modification design in step (1) includes iron-carbon-sulfur waste residue and modification auxiliary materials, with a mass percentage of 70-90:10-30, and the sum of the mass percentages of the iron-carbon-sulfur waste residue and modification auxiliary materials is 100%; the modification auxiliary materials include lead tailings, sodium carbonate, barium carbonate and clarifying agent, with a mass ratio of 10-20:2-8:2-4:0.1-5; (2) The modified waste residue precursor obtained in step (1) is pretreated, subjected to restricted heat treatment melting and tail gas recovery, and the melt is water quenched to obtain the modified base material; the restricted heat treatment temperature is 1420-1450℃; the restricted heat treatment heating rate is 8-10℃ / min in the 30-300℃ range; 3-5℃ / min in the 300-600℃ range; and 6-8℃ / min in the 600-1450℃ range. The heat preservation time in step (2) for the 300-600℃ temperature range is 0.2-0.5 h, and the heat preservation time for the 1420-1450℃ temperature range is 1-2.5 h; (3) The modified base material obtained in step (2) is first subjected to sintering pretreatment to obtain a base material green body, and then the base material green body is subjected to multi-step graded heat treatment. The multi-step graded heat treatment is a sintering crystallization treatment of the base material green body. According to the thermal analysis curve, 11 graded temperature heat treatment conditions are set, namely 130-160℃ / 1-2.5 h, 400-500℃ / 1-2.5 h, 550-600℃ / 1-2.5 h, 650-750℃ / 1-2.5 h, 780-810℃ / 1-2.5 h, 850-900℃ / 1-2.5 h, 1000-1020℃ / 1-2.5 h, 1040-1060℃ / 1-2.5 h, 990-1110℃ / 1-2.5 h, and 1130-1160℃ / 1-2.5 h. h, 1180-1200℃ / 1-2.5 h; heating rate at 30-500℃ is 5-8℃ / min; heating rate at 500-750℃ is 1-3℃ / min; heating rate at 750-1200℃ is 4-6℃ / min; The lead tailings comprises SiO2, Al2O3, and Fe2O3 in a weight ratio of 55-70:8-20:3-8; the lead tailings also comprises three or at least four of the following components: CaO, Na2O, K2O, MgO, ZnO, TiO2, and CuO, with each component accounting for 0-5 wt% of the lead tailings, but not 0.

2. The method according to claim 1, characterized in that: The clarifying agent includes one or a combination of at least two of CeO2, Sb2O3, NaSbO3, and NaNO3; the proportions of CeO2, Sb2O3, NaSbO3, and NaNO3 in the modified waste residue precursor raw material are each 0.1-5 wt%.

3. The method according to claim 1, characterized in that: The iron-carbon-sulfur waste residue mentioned in step (1) includes the components SiO2, Fe2O3, CaO, C, Al2O3, ZnO, MnO, CuO, Na2O, MgO and SO3, and the weight ratio of each component is 20-35:15-35:10-20:1-3:3-5:2-4:0.4-4:2-5:0.6-2:0.5-2:0.9-3.

4. The method according to claim 1, characterized in that: The pretreatment in step (2) includes drying, ball milling, and multi-stage sieving of the modified waste residue precursor; The drying temperature in step (2) is 120-160℃; the ball milling speed is 350-450rpm; the multi-stage screening includes first removing rust impurities by using a double sieve method, and then fully ball milling the modified waste residue precursor after screening and then screening it again; the screening particle size is 180-200 mesh.

5. The method according to claim 1, characterized in that: The restrictive heat treatment melting described in step (2) is carried out in a box furnace; The exhaust gas recovery described in step (2) is a CO2 / SO ... x Exhaust gas recovery device; The temperature of the water used in step (2) during water quenching is 15-30℃.

6. The method according to claim 1, characterized in that: The sintering pretreatment in step (3) includes filtering, drying, ball milling, and sieving the modified base material; the drying temperature is 120-160℃; the ball milling speed is 350-450rpm; and the sieving particle size is 180-200 mesh.

7. The method according to claim 1, characterized in that: Step (3) is performed in a KSL1200 crystallization furnace; The modified base material described in step (3) is subjected to multi-stage sieving before heat treatment to obtain 180-200 mesh modified base material.

8. The use of the calcium iron garnet-based microcrystalline glass obtained by the method as described in any one of claims 1-7.

9. The application of the microcrystalline glass as described in claim 8 in the fields of construction, metallurgy, machinery or chemical industry.

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