Multi-source iron-containing solid waste cold solid ball and preparation method thereof

Abstract

The invention relates to a multi-source iron-containing solid waste cold solid ball and a preparation method, and belongs to the technical field of solid waste treatment. The cold bonding ball comprises the following raw materials in parts by weight: 40-70 parts of iron-containing dust mud, 15-40 parts of a secondary metal material, 1-5 parts of a binder and 5-12 parts of a liquid modifier. A consolidation system with continuous and reasonable gradation is formed by utilizing pore filling of the fine-grained iron-containing dust mud and an aggregate bridging effect of the coarse-grained secondary metal material, so that the compactness and the compressive strength are improved; chloride ions in high-salinity wastewater are used for modifying raw materials, oxidation phase change of metal iron and low-valence iron oxide in a secondary metal material is promoted, a high-strength binding phase is generated, the compressive strength of the pellets is effectively improved, co-treatment of wastewater and multi-source solid waste is achieved, and under the condition that the cost of a binding agent is not additionally increased, the cost of the binding agent is reduced. And the cold consolidation strength of iron-containing solid wastes with different components is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solid waste treatment, and in particular to a multi-source iron-containing solid waste cold-solidified ball and a preparation method thereof. Background Art

[0002] A large amount of iron-containing solid waste is generated during the steel smelting process, such as blast furnace slag, steel slag, iron-containing dust and mud, waste refractory materials, iron oxide scale and desulfurized gypsum. According to the different physical and chemical properties of various solid wastes, they are recycled through a variety of environmentally friendly treatment methods. For example, raw material dust removal ash, steelmaking primary ash, etc. can be used for homogenization granulation and directly reused for sintering; iron oxide scale, slag steel, high iron and low zinc dust and mud are cold pressed and reused in torpedo tanks or converters; high zinc dust and mud are directly reduced and dezincified by fire to produce metallized materials and secondary zinc oxide powder. Among them, the production of cold solidified balls by cold consolidation process has been widely used. Various iron-containing solid wastes are prepared into cold materials with suitable strength and composition, which are used to replace part of sintered ore or scrap steel and added to the converter, which can improve the slag performance of converter smelting, reduce the use of flux, and reduce production costs. This process is particularly suitable for iron-containing solid wastes with low zinc content and high iron content.

[0003] However, due to the instability of the iron-containing solid waste components and different physical and chemical properties, there are still problems such as low consolidation strength, high pulverization rate and high binder cost. Especially when OG mud and fine-grained dust ash are used as the main raw materials, the amount of binder added is usually more than 5%, and the pulverization rate is as high as 15% to 20%. On the other hand, the slag iron powder obtained by magnetic separation from desulfurized slag, the slag steel powder obtained by magnetic separation from steel slag, and the metal material after high-zinc dust mud reduction and dezincification have high pulverization rate and fine particle size, making it difficult to directly return to steelmaking applications; and when such materials are cold-pressed alone, the particle size distribution is unreasonable, and a large amount of organic and inorganic binders need to be added, and the cost of briquetting remains high. Summary of the invention

[0004] The present application provides a multi-source iron-containing solid waste cold-consolidated ball and a preparation method to solve the following technical problem: how to improve the cold consolidation strength of iron-containing solid wastes of different components without increasing the cost of the binder.

[0005] In a first aspect, an embodiment of the present application provides a multi-source iron-containing solid waste cold-solidified ball. The raw materials of the cold-solidified ball include, by weight: 40 to 70 parts of iron-containing dust and mud, 15 to 40 parts of secondary metal materials, 1 to 5 parts of binder and 5 to 12 parts of liquid modifier.

[0006] Optionally, the iron-containing dust mud includes converter OG mud, sintering dust ash and refining dust ash.

[0007] Optionally, the secondary metal material includes at least one of oxidized iron scale, slag steel powder, slag iron powder, and fine-grained undersize material obtained by direct reduction.

[0008] Optionally, the binder is at least one of pregelatinized starch, calcium lignin sulfonate, and sodium cellulose.

[0009] Optionally, the liquid modifier includes high-salt wastewater.

[0010] Optionally, the particle size of the iron-containing dust is ≤0.15 mm.

[0011] Optionally, the particle size of the secondary metal material is less than 3 mm.

[0012] Optionally, in the cold-solidified ball, the mass fraction of metallic iron is >15%.

[0013] In a second aspect, an embodiment of the present application provides a method for preparing the cold-solidified ball described in the first aspect, the method comprising:

[0014] According to the weight proportions, the iron-containing dust, the secondary metal material and the binder are first mixed to obtain a first mixed material;

[0015] Performing a second mixing of the first mixed material and the liquid modifier to obtain a second mixed material;

[0016] Pressing the second mixed material into a shape to obtain a wet ball;

[0017] The wet bulbs are subjected to natural curing and low-temperature drying curing in sequence to obtain cold-solidified bulbs.

[0018] Optionally, the second mixing time is ≥20 min.

[0019] Optionally, the water content of the second mixture is 8% to 12% by mass.

[0020] Optionally, the temperature of the low-temperature drying and curing is ≤150°C.

[0021] Optionally, the powder rate of the cold-solidified ball is less than 8%, and the single-ball compressive strength of the cold-solidified ball is greater than 1000N.

[0022] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0023] The embodiment of the present application provides a multi-source iron-containing solid waste cold-solidified ball, and the raw materials of the cold-solidified ball include, by weight, 40 to 70 parts of iron-containing dust mud, 15 to 40 parts of secondary metal materials, 1 to 5 parts of binder, and 5 to 12 parts of liquid modifier. The pore filling of fine-grained iron-containing dust mud and the aggregate bridging effect of coarse-grained secondary metal materials are used to form a continuous and reasonable consolidation system to improve the density and compressive strength; the chloride ions in high-salt wastewater are used to modify the raw materials to promote the oxidation phase change of metallic iron and low-valent iron oxides in the secondary metal materials, produce a high-strength bonding phase, effectively improve the compressive strength of the pellets, realize the coordinated disposal of wastewater and multi-source solid waste, and improve the cold consolidation strength of iron-containing solid wastes of different components without additionally increasing the cost of the binder. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 A schematic flow chart of a method for preparing cold-solidified balls of iron-containing solid waste from multiple sources provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0029] In this document, the terms including "including" and "including" mean "including but not limited to". Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, and "plurality" means two or more; "at least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts" such as parts by weight and parts by mass indicate the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, if the weight ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond to the proportional numbers in the proportional formula in the order of description, that is, the weight of substance A: the weight of substance B: the weight of substance C = 1:2:3.

[0030] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0031] In a first aspect, an embodiment of the present application provides a multi-source iron-containing solid waste cold-solidified ball. The raw materials of the cold-solidified ball include, by weight: 40 to 70 parts of iron-containing dust and mud, 15 to 40 parts of secondary metal materials, 1 to 5 parts of binder and 5 to 12 parts of liquid modifier.

[0032] In some embodiments, the iron-containing dust mud includes converter OG mud, sintering dust and refining dust.

[0033] In some embodiments, the secondary metal material includes at least one of iron oxide scale, slag steel powder, slag iron powder, and fine-grained undersize material obtained by direct reduction.

[0034] In some embodiments, the binder is at least one of pregelatinized starch, calcium lignin sulfonate, and sodium cellulose.

[0035] In some embodiments, the liquid modifier comprises high-salinity wastewater.

[0036] Iron-containing dust mud includes converter OG mud, sintering dust removal ash and refining dust removal ash. These dust muds have different iron contents, particle sizes and chemical compositions. Through reasonable proportions, a continuous and reasonable consolidation system can be formed. Specifically, converter OG mud is the product of converter OG wet dust removal, which has the characteristics of high iron content, fine particle size and high viscosity; the iron content in sintering dust removal ash is low, the particle size is fine, and the sodium chloride and potassium chloride content are high; the alkaline oxide content in refining dust removal ash is high, the particle size is fine, and the surface hydrophilicity is poor. Sintering dust removal ash and refining dust removal ash can increase the alkalinity of cold-solidified balls. Exemplarily, the weight parts of iron-containing dust mud can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, etc.

[0037] Secondary metal materials include iron oxide scale, slag steel powder, slag iron powder and fine-grained screened materials obtained by direct reduction, etc. These materials are rich in metallic iron and low-valent iron oxides, and have a certain particle size distribution, which can play a skeleton and bridging role in cold solid balls. In the embodiment of the present application, slag steel powder and slag iron powder can be obtained by magnetic separation from steel slag, or by magnetic separation from desulfurized slag. Specifically, the iron oxide scale has a high content of low-valent iron oxide, a coarse particle size, and is in the form of flakes and strips; slag steel powder and slag iron powder have a high content of metallic iron and a low content of impurities such as gangue. The fine-grained screened materials obtained by direct reduction can be metallized materials after zinc-containing dust and mud are dezincified, and specifically can be kiln slag of a rotary kiln or screened powder of a rotary hearth furnace. Exemplarily, the weight parts of the secondary metal materials can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc.

[0038] Binders such as pregelatinized starch, calcium lignin sulfonate, sodium cellulose, etc. are used to improve the balling of the material and the consolidation strength of the cold-solidified ball. The binder mainly acts on iron-containing dust and mud. Specifically, calcium lignin sulfonate has a strong dispersing effect and can be adsorbed on the surface of mineral particles, undergoing chelation and coordination reactions to produce adhesion. Exemplarily, the weight parts of the binder can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0039] Liquid modifier is mainly high-salt wastewater, containing chloride ions and other ions, which can promote the oxidation phase change of metallic iron and low-valent iron oxides to form a high-strength bonding phase. Liquid modifier mainly acts on secondary metal materials. Specifically, the high-salt wastewater can come from sintering, pelletizing activated carbon desulfurization process or high-chlorine dust removal ash washing water, and further, the chloride ion content is ≥50g / L. Through the modification treatment of high-salt wastewater, the metallic iron or low-valent iron oxide in the cold solid ball system is promoted to undergo phase change, forming FeOOH with higher density of flaky structure, and enhancing the consolidation strength of the pellets. On the other hand, the salt solution can improve the stability of the binder starch gel, enhance the network strength of the gel, and improve the bonding force between different components. Exemplary, the weight parts of the liquid modifier can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, etc.

[0040] The embodiment of the present application performs cold consolidation treatment on iron-containing dust mud of different component properties and multiple secondary metal materials, making full use of the pore filling of fine-grained dust mud and the aggregate bridging effect of coarse-grained secondary metal materials to form a continuous and reasonable consolidation system, thereby improving the density and compressive strength; using chloride ions in high-salt wastewater to modify the raw materials, promoting the oxidation phase change of metallic iron and low-valent iron oxides in the secondary metal materials, producing a high-strength bonding phase, effectively improving the compressive strength of the pellets, and realizing the coordinated disposal of wastewater and multi-source solid waste; making full use of potassium chloride and sodium chloride in sintering dust ash and alkaline oxides in refined dust ash, and digesting and increasing the viscosity of the raw materials by dry-wet mixing with OG mud. Without increasing the cost of the binder, the dust ash that is difficult to handle in the steel plant is added to the cold-solidified balls, and the short-process resource utilization is realized in the converter.

[0041] In some embodiments, the particle size of the iron-containing dust is ≤ 0.15 mm.

[0042] In the embodiment of the present application, the particle size of the iron-containing dust is ≤0.15mm, and the iron-containing dust with a particle size less than 43μm accounts for more than 80%. This type of dust has a fine particle size and a high specific surface area, which helps to evenly distribute the binder in the cold-pressed ball system, thereby improving the balling of the material. Exemplarily, the particle size of the iron-containing dust can be 0.01mm, 0.03mm, 0.05mm, 0.07mm, 0.09mm, 0.11mm, 0.13mm, 0.15mm, etc.

[0043] In some embodiments, the particle size of the secondary metal material is <3 mm.

[0044] In the embodiment of the present application, the particle size of the secondary metal material is less than 3 mm, and the preferred particle size range is 0.15 mm to 2.36 mm, accounting for more than 60%. On the one hand, at the preferred particle size, the secondary metal material can undergo a sufficient oxidation reaction under the action of the modifier. On the other hand, this type of material has a rough surface and irregular shape, which can play a skeleton and bridging role in fine-grained powder materials, optimize the particle size grading, and thus improve the consolidation strength of the pellets. Exemplarily, the particle size of the secondary metal material can be 0.05 mm, 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, etc.

[0045] In some embodiments, the mass fraction of metallic iron in the cold-solidified ball is >15%.

[0046] In the embodiment of the present application, the iron-containing dust and secondary metal material contain metallic iron and low-valent iron oxides. Furthermore, the mass fraction of metallic iron in the cold-solidified ball is greater than 15%, which is conducive to generating sufficient bonding phase. For example, the mass fraction of metallic iron can be 16%, 21%, 26%, 31%, 36%, etc.

[0047] In summary, the embodiment of the present application provides a multi-source iron-containing solid waste cold solid ball, which has the following advantages:

[0048] Consolidation system with continuous and reasonable gradation: Through the pore filling of fine-grained iron-containing dust and the aggregate bridging effect of coarse-grained secondary metal materials, a consolidation system with continuous and reasonable gradation is formed, which improves the density and compressive strength of the cold-solidified ball.

[0049] Co-treatment of wastewater and solid waste: Using high-salt wastewater as a liquid modifier not only realizes the resource utilization of wastewater, but also promotes the oxidation phase change of metallic iron in solid waste and improves the strength of cold-solidified balls.

[0050] Low cost and high efficiency: Without increasing the cost of binder, the cold consolidation strength of iron-containing solid waste of different components is improved by optimizing the raw material ratio and process design, thus achieving maximum utilization of resources and improvement of economic benefits.

[0051] Therefore, the multi-source iron-containing solid waste cold solidified balls provided in the embodiment of the present application not only solve the problem of solid waste treatment and resource recycling in steel enterprises, but also achieve a win-win situation of environmental and economic benefits. This innovative technical solution has broad application prospects and market potential.

[0052] Figure 1 A schematic flow chart of a method for preparing cold-solidified balls of iron-containing solid waste from multiple sources provided in an embodiment of the present application.

[0053] See also Figure 1 In a second aspect, an embodiment of the present application provides a method for preparing the cold-solidified ball described in the first aspect, the method comprising:

[0054] S1. Mixing the iron-containing dust, the secondary metal material and the binder according to the weight parts to obtain a first mixture;

[0055] In the embodiment of the present application, the converter OG mud, sintering dust ash and refining dust ash are mixed with dry and wet materials to obtain iron-containing dust mud. The converter OG mud needs to be dried to a moisture content of 8% to 15%, and then mixed with sintering dust ash and refining dust ash for dry and wet materials and digested for 9h to 11h. This makes the moisture content of the material more uniform and allows the calcium oxide in the dust ash to be fully digested in the material.

[0056] S2, performing a second mixing of the first mixed material and the liquid modifier to obtain a second mixed material;

[0057] In some embodiments, the second mixing time is ≥ 20 min.

[0058] In some embodiments, the water content of the second mixture is 8% to 12% by mass.

[0059] Limiting the second mixing time to ≥ 20 min can ensure the infiltration of the mixed material by the high-salt wastewater and increase the viscosity of the material. Exemplarily, the second mixing time can be 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, etc. At the same time, by adding a liquid modifier, limiting the water content of the second mixed material to 8% to 12%, the waste liquid modification effect and the appropriate moisture content of the ball can be guaranteed. Exemplarily, the water content of the second mixed material can be 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, etc.

[0060] S3, pressing the second mixed material into a shape to obtain a wet ball;

[0061] S4, performing natural curing and low-temperature drying curing on the wet bulb in sequence to obtain a cold-solidified bulb.

[0062] The purpose of natural curing and low-temperature drying curing is that natural curing provides micro-area rusting conditions for iron-containing metal materials, enhances the cohesion between material components, and improves the strength of cold-solidified balls. In the embodiment of the present application, the temperature of natural curing is 5°C to 30°C, and the time of natural curing is 24h to 72h. If the natural curing time is shorter than 24h, the content of the iron-containing bonding phase produced is low, which is not enough to produce sufficient bridging and bonding effects, and the compressive strength is low; if the natural curing time is longer than 72h, the moisture content of the pellets decreases slowly, which easily causes the moisture content of the cold-solidified balls to exceed the standard; at the same time, the compressive strength is not significantly improved, and the production rhythm is affected. If it is directly dried without natural curing, the salt solution content in the system is too low to support the conversion of metallic iron and low-valent iron oxides into iron-containing bonding phases.

[0063] In some embodiments, the temperature of the low-temperature drying and curing is ≤150°C.

[0064] The drying process can further reduce the capillary water in the pellets, increase the capillary force, and improve the compressive strength of the pellets; at the same time, it can reduce the bound water of the binder to ensure that the moisture content of the finished ball meets the requirements. When the temperature is higher than 150°C, the water evaporates too quickly, resulting in cracks and pores inside, causing the strength of the pellets to decrease. Exemplarily, the temperature of low-temperature drying and curing can be 140°C, 142°C, 144°C, 146°C, 148°C, 150°C, etc.

[0065] In some embodiments, the powder rate of the cold-solidified ball is less than 8%, and the single ball compressive strength of the cold-solidified ball is greater than 1000N.

[0066] In the embodiment of the present application, the powder rate of the cold-solidified ball is less than 8%, indicating that the pellet structure is compact and not easy to break. Exemplarily, the powder rate of the cold-solidified ball can be 6.3%, 6.6%, 6.9%, 7.2%, 7.5%, etc. The single ball compressive strength of the cold-solidified ball is greater than 1000N, and has high strength and stability. Exemplarily, the single ball compressive strength of the cold-solidified ball can be 1100N, 1200N, 1300N, 1400N, 1500N, etc.

[0067] The product prepared by the preparation method of the cold-solid ball is the above-mentioned multi-source iron-containing solid waste cold-solid ball. Since the preparation method of the cold-solid ball adopts part or all of the technical solutions of the multi-source iron-containing solid waste cold-solid ball embodiment, it at least has all the beneficial effects brought by the technical solutions of the multi-source iron-containing solid waste cold-solid ball embodiment, which will not be repeated here one by one.

[0068] The present application is further described below in conjunction with specific embodiments. The experimental methods in the following embodiments that do not specify specific conditions are usually measured in accordance with national standards / industry standards; if there are no corresponding national standards / industry standards, they are measured in accordance with common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0069] Example 1

[0070] A multi-source iron-containing solid waste cold solid ball, the raw materials include, by weight: 55 parts of converter OG mud, 5 parts of sintering dust ash, 5 parts of refining dust ash, 20 parts of iron oxide scale, 8 parts of slag steel powder, 2 parts of binder, and 5 parts of high-salt wastewater;

[0071] A method for preparing cold-solidified balls of iron-containing solid waste from multiple sources, comprising:

[0072] Step 1: by mass percentage, the converter OG mud with a moisture content of 10% is mixed with 5 parts of dry-based sintering dust ash and 5 parts of dry-based refining dust ash for dry-wet mixing, and digested for 10 hours to obtain iron-containing dust mud;

[0073] Step 2: Add 20 parts of iron oxide, 8 parts of slag steel powder and 2 parts of binder to the iron-containing dust obtained in step 1, and mix them in a mixer to obtain a first mixture; the particle sizes of the iron oxide and slag steel powder are both below 3 mm.

[0074] Step 3: Add 5 parts of high-salt wastewater to the first mixture, wherein the chloride ion concentration of the high-salt wastewater is 50 g / L, and vigorously mix again for 20 minutes to obtain a second mixture;

[0075] Step 4: Pressing the second mixed material into a shape in a high-pressure roller press to obtain a wet ball of a certain size;

[0076] Step 5: After the wet bulb is naturally cured for 24 hours, it is placed in a dryer and dried at 100°C for 2 hours to obtain a finished cold-solidified ball.

[0077] Example 2

[0078] Compared with Example 1, the difference between Example 2 and Example 1 is that, in parts by weight, the raw materials include: 30 parts of converter OG mud, 5 parts of sintering dust ash, 5 parts of refining dust ash, 20 parts of iron oxide scale, 30 parts of rotary kiln slag, 1.5 parts of binder, and 8.5 parts of high-salt wastewater.

[0079] Step 3: Add 5 parts of high-salt wastewater to the first mixture, wherein the chloride ion concentration of the high-salt wastewater is 80 g / L, and vigorously mix again for 20 minutes to obtain a second mixture.

[0080] Example 3

[0081] Compared with Example 1, the difference between Example 3 and Example 1 is that, in parts by weight, the raw materials include: 55 parts of converter OG mud, 10 parts of sintering dust ash, 5 parts of refining dust ash, 15 parts of iron oxide scale, 5 parts of rotary hearth furnace undersize powder, 3 parts of binder, and 7 parts of high-salt wastewater.

[0082] Step 5: After the wet bulb is naturally cured for 72 hours, it is placed in a dryer and dried at 100°C for 2 hours to obtain a finished cold-solidified ball.

[0083] Example 4

[0084] Compared with Example 1, the difference between Example 4 and Example 1 is that, in parts by weight, the raw materials include: 55 parts of converter OG mud, 10 parts of sintering dust ash, 5 parts of refining dust ash, 20 parts of iron oxide scale, 8 parts of slag steel powder, 5 parts of binder, and 5 parts of high-salt wastewater.

[0085] Step 5: After the wet bulb is naturally cured for 48 hours, it is placed in a dryer and dried at 100°C for 2 hours to obtain a finished cold-solidified ball.

[0086] Comparative Example 1

[0087] Compared with Example 1, the difference between Comparative Example 1 and Example 1 is: Step 3: 5 parts of industrial water are added to the first mixture to replace the high-salt wastewater, and the mixture is vigorously mixed for 20 minutes to obtain a second mixture.

[0088] Comparative Example 2

[0089] Comparative Example 2 is compared with Example 1. The difference between Comparative Example 2 and Example 1 is that, in parts by weight, the raw materials include:

[0090] 75 parts of converter OG mud, 5 parts of sintering dust ash, 5 parts of refining dust ash, 5 parts of binder, and 5 parts of high-salt wastewater;

[0091] Comparative Example 3

[0092] Compared with Example 1, the difference between Comparative Example 3 and Example 1 is that: Step 5: directly drying the wet bulb at a drying temperature of 100° C., and obtaining a finished cold-solidified bulb after drying for 2 hours.

[0093] The cold-solidified balls prepared in Examples 1-4 and Comparative Examples 1-3 were inspected and tested for performance. The results are shown in Table 1.

[0094] Table 1

[0095] project Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Compressive strength / N 1060 1495 1326 1388 820 766 679 Metal iron / % 19.09 35.60 15.22 27.16 19.09 7.32 19.09 TFe / % 60.85 58.46 53.75 55.11 60.85 54.70 60.85

[0096] It can be seen from Table 1 that the raw materials and preparation process of the cold-solidified ball of the embodiment are both within the required range of the present invention, and the compressive strength is good.

[0097] In Comparative Example 1, the high-salt wastewater is replaced with ordinary industrial water. There is not enough salt solution to stimulate the metallic iron and low-valent iron oxides in the components to undergo oxidative phase change, the bonding phase FeO(OH) is reduced, and the compressive strength decreases.

[0098] The raw material of Comparative Example 2 is iron-containing dust and mud, and no secondary metal material is added. The system is composed of fine-grained particles, and the grading is unreasonable; the metallic iron content in the components is low, and the compressive strength of the pellets mainly depends on the bonding force formed by the binder and the iron-containing dust and mud, and the strength is low.

[0099] In Comparative Example 3, the wet ball is directly dried without natural curing, the water in the pellets evaporates too quickly, the hydration reaction between the binder and the components, and the modification effect of the high-salt wastewater on the iron-containing phase are not fully exerted, so the overall strength is reduced.

[0100] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0101] The embodiments of the present invention achieve low-cost consolidation and resource utilization of various iron-containing solid wastes through technical means such as component synergy, particle size optimization, and modification treatment among iron-containing solid wastes from different sources.

[0102] The method for preparing cold-solidified balls of iron-containing solid waste from multiple sources provided in the embodiment of the present invention realizes the resource utilization and coordinated disposal of iron-containing dust and mud, secondary metal materials, and industrial waste liquid.

[0103] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present application, but will conform to the widest range consistent with the principles and novel features applied for by the present application.

Claims

1. A multi-source iron-containing solid waste cold-solidified ball, wherein the raw materials of the cold-solidified ball include, by weight: 40 to 70 parts of iron-containing dust, 15 to 40 parts of secondary metal materials, 1 to 5 parts of binder and 5 to 12 parts of liquid modifier.

2. The cold solid ball according to claim 1, characterized in that: The iron-containing dust includes converter OG mud, sintering dust and refining dust.

3. The cold solid ball according to claim 1, characterized in that: The secondary metal material comprises at least one of oxidized iron scale, slag steel powder, slag iron powder, and fine-grained undersize material obtained by direct reduction.

4. The cold solid ball according to claim 1, characterized in that: The binder is at least one of pregelatinized starch, calcium lignin sulfonate and sodium cellulose.

5. The cold solid ball according to claim 1, characterized in that: The liquid modifier includes high-salinity wastewater.

6. The cold solid ball according to claim 1, characterized in that: The particle size of the iron-containing dust is ≤0.15 mm; and / or, The particle size of the secondary metal material is less than 3 mm.

7. The cold solid ball according to claim 1, characterized in that: In the cold-solidified ball, the mass fraction of metallic iron is greater than 15%.

8. A method for preparing a cold solid ball according to any one of claims 1 to 7, the method comprising: According to the weight proportions, the iron-containing dust, the secondary metal material and the binder are first mixed to obtain a first mixed material; Performing a second mixing of the first mixed material and the liquid modifier to obtain a second mixed material; Pressing the second mixed material into a shape to obtain a wet ball; The wet bulbs are subjected to natural curing and low-temperature drying curing in sequence to obtain cold-solidified bulbs.

9. The method according to claim 8, characterized in that The second mixing time is ≥ 20 min; and / or, The water content of the second mixture is 8% to 12% by mass; and / or, The temperature of the low-temperature drying and curing is ≤150°C.

10. The method according to claim 8, characterized in that The powder rate of the cold-solidified ball is less than 8%, and the single-ball compressive strength of the cold-solidified ball is greater than 1000N.

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