CN110980753B - Process for producing high-quality sodium silicate by adopting high-silicon iron ore - Google Patents
Process for producing high-quality sodium silicate by adopting high-silicon iron ore Download PDFInfo
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Abstract
A process for producing high-quality sodium silicate by adopting high-silicon iron ores comprises the following steps: 1) preparing a reducing material: preparing high-silicon iron ore into pellets to be sintered; 2) reducing the pellets to be sintered: heating the pellets to be sintered at high temperature to obtain reduced pellets; 3) crushing and grinding to obtain high-silicon tailings: crushing the reduction pellets to obtain reduced crushed materials, grinding the reduced crushed materials by using an ultra-fine grinding device to obtain reduced powder, and magnetically separating the reduced powder to obtain high-silicon tailings; 4) extracting a sodium silicate solution: and adding alkali liquor into the high-silicon tailings to obtain a solid-liquid mixture, and leaching the sodium silicate solution. The application provides a technical scheme, its manufacturing cost that can reduce sodium silicate improves sodium silicate's production quality.
Description
Technical Field
The invention relates to a process for producing sodium silicate, in particular to a process for producing high-quality sodium silicate by adopting high-silicon iron ores, belonging to the technical field of iron ore metallurgy.
Background
By 2018, the reserve of iron ore resources in China is about 470 hundred million t, but 97% of the iron ore resources are lean ores, the average iron grade is only 34.29%, 14 points lower than the average iron grade (48.24%) of the iron ores in the world, and 22 points lower than the average iron grade (56.07%) of the iron ores in four mines. The ore has huge reserves in places such as Heyang, Ningxiang and the like in Hunan China, the reserves of the iron ore at the entrance of a cave in the Heyang market only reach 5-6 hundred million tons, but the iron-containing minerals of the ores generally have extremely fine embedded granularity which reaches-400 meshes or even more than-600 meshes, and the conventional ore dressing means is difficult to effectively enrich.
The traditional high-temperature metallurgical process for treating iron ore mainly comprises magnetizing roasting, direct reduction (coal-based method and gas-based method) and burden sintering-blast furnace iron-making method. Although the magnetizing roasting is a better treatment process for recovering metallic iron from iron ore, the product is magnetite and a small amount of float bodies, and the product has low grade and low price. Meanwhile, the process, whether a rotary kiln method, a shaft furnace method or a fluidized bed method, is in the laboratory research stage at present because the problems of low iron recovery rate, difficult homogenization of reduction degree, large-scale equipment and the like are not solved. The ore blending sintering-blast furnace method provides a thought for the utilization of low-grade ores in China, but the method has high energy consumption and large slag quantity per ton of molten iron, thereby not only wasting precious coke resources, but also causing difficulty in smooth operation of furnace burden. Under the call of national energy conservation and environmental protection and the policy of blast furnace concentrate, the process is gradually eliminated. At present, oxidized pellets are needed to be used in a gas-based method and a partial coal-based method in the traditional direct reduction process, and energy consumption per ton of high-silicon low-grade iron ore is very high by adopting the oxidized pellets-direct reduction process, so that the energy-saving and environment-friendly advantages are not achieved. Part of the coal-based reduction process can adopt ore-coal composite pellets for production, but the high-silicon iron ore can generate a large amount of fayalite under the high-temperature condition of the traditional direct reduction, so that the iron recovery fails. Therefore, it is difficult to efficiently recover iron resources from high-silicon low-grade iron ores.
Meanwhile, aiming at the characteristic that the high-silicon iron ore has high silicon content, if the process link for producing the reduced iron powder can be fully utilized, the high-silicon tailings can be assisted to be treated in the later period to produce high-quality sodium silicate, and the by-product value of the iron powder reduction process can be effectively improved.
Therefore, how to provide a process for producing high-quality sodium silicate by using high-silicon iron ore, which can reduce the production cost of sodium silicate and improve the production quality of sodium silicate, is a technical problem to be solved urgently by technical personnel in the field.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to produce the sodium silicate by using the high-silicon iron ore, reduce the production cost of the sodium silicate and improve the production quality of the sodium silicate. The invention provides a process for producing high-quality sodium silicate by adopting high-silicon iron ore, which comprises the following steps: 1) preparing a reducing material: the high-silicon iron ore is made into pellets to be sintered. 2) Reducing the pellets to be sintered: and heating the pellets to be sintered at high temperature to obtain the reduced pellets. 3) Crushing and grinding to obtain high-silicon tailings: crushing the reduction pellets to obtain reduced crushed materials, grinding the reduced crushed materials by using an ultra-fine grinding device to obtain reduced powder, and magnetically separating the reduced powder to obtain high-silicon tailings. 4) Extracting a sodium silicate solution: and adding alkali liquor into the high-silicon tailings to obtain a solid-liquid mixture, and leaching the sodium silicate solution.
According to the embodiment of the invention, the process for producing the high-quality sodium silicate by adopting the high-silicon iron ore is provided,
a process for producing high-quality sodium silicate by adopting high-silicon iron ores comprises the following steps:
1) preparing a reducing material: the high-silicon iron ore is made into pellets to be sintered.
2) Reducing the pellets to be sintered: and heating the pellets to be sintered at high temperature to obtain the reduced pellets.
3) Crushing and grinding to obtain high-silicon tailings: crushing the reduction pellets to obtain reduced crushed materials, grinding the reduced crushed materials by using an ultra-fine grinding device to obtain reduced powder, and magnetically separating the reduced powder to obtain high-silicon tailings.
4) Extracting a sodium silicate solution: and adding alkali liquor into the high-silicon tailings to obtain a solid-liquid mixture, and leaching the sodium silicate solution.
Preferably, the discharge granularity of the superfine grinding device in the step 3) is 600-900 meshes. Preferably 750-850 mesh.
Preferably, the temperature of the low-temperature heating in the step 2) is 800-1200 ℃, preferably 900-1000 ℃, and more preferably 900-980 ℃.
Preferably, the time for low-temperature heating in the step 2) is 15-45min, preferably 20-30 min.
Preferably, the sodium silicate solution leached in step 4) is weakly alkaline.
Preferably, in the step 4), the sodium silicate solution is leached from the high-silicon tailings by adopting a counter-current leaching method. The method comprises the following steps.
4a) Forward alkaline leaching of high-silicon tailings: and the high-silicon tailings subjected to alkaline leaching in the first layer of alkaline leaching unit enter a second layer of alkaline leaching unit for alkaline leaching. And the high-silicon tailings subjected to alkaline leaching in the second-layer alkaline leaching unit enter a third-layer alkaline leaching unit for alkaline leaching.
4b) Reverse discharge of leaching solution: and adding alkali liquor into the third layer of alkaline leaching unit, adding the third layer of leaching solution into the second layer of alkaline leaching unit, adding the second layer of leaching solution into the first layer of alkaline leaching unit, and introducing the leaching solution of the first layer of alkaline leaching unit into a sodium silicate storage container.
4c) Keeping alkalescence: and (3) supplementing alkali liquor to the first layer of alkali leaching unit and the second layer of alkali leaching unit, and keeping the pH value of the solution of the first layer of alkali leaching unit and the second layer of alkali leaching unit to be 7-9, preferably 7.5-8.5.
Preferably, the step 1) comprises the following steps:
1a) crushing the iron ore to obtain iron ore crushed materials, and crushing the internal blending coal to obtain internal blending coal crushed materials.
1b) The iron ore crushed aggregates and the internal blending coal crushed aggregates are mixed and ground under the action of a binder to obtain the pellet raw material.
1c) Pelletizing raw materials are made into pellets in a pelletizing device.
1d) And (3) drying the pellets: and drying and preheating the pellets in a first drying device to obtain the pellets to be sintered.
Preferably, the sintering flue gas discharged in the step 2) is introduced into the superfine grinding device in the step 3) to prevent iron from being oxidized.
Preferably, the sintering flue gas discharged in the step 2) is firstly introduced into a first drying device to dry the pellets, and then introduced into the superfine grinding device in the step 3) to prevent iron oxidation.
Preferably, the filter residue left after the alkaline leaching in the step 4) is used as a binder to participate in the preparation process of the pellets to be sintered in the step 1).
Preferably, the sintering flue gas generated in the step 2) exchanges heat with the solid-liquid mixture in the step 4).
In the application, after the high-silicon iron ore is made into sintered pellets to be sintered, the sintered pellets enter a direct reduction system, oxidation-reduction reaction is carried out on the sintered pellets through high-temperature heating in the direct reduction system, and the iron ore in the pellets is reduced to obtain small iron monomers so as to obtain the reduced pellets. Crushing, grinding and selecting the reduction pellets, crushing the reduction pellets to obtain reduction crushed materials, and grinding the reduction crushed materials into reduction powder by using an ultra-fine grinding device. And magnetically separating the reduced powder to obtain reduced iron powder, and obtaining the residual high-silicon tailings. And finally, carrying out alkaline leaching on the high-silicon filter residue to obtain sodium silicate. According to the technical scheme provided by the application, in the crushing and grinding process in the step 3), the reducing pellets are finally ground into superfine powder. That is, the high silicon tailings are also in the form of ultrafine powder, so that the specific surface area of the high silicon tailings is increased. So that the high-silicon tailings can react with the alkali liquor more fully and quickly in the alkaline leaching process in the step 4). At the same time, since the silicon oxide is ground into ultra-fine powder, the particle size of the silicon oxide is small. Silicon oxide is mostly present in the form of silicon-oxygen tetrahedra. Then during the reaction of the silica with the base, the silica is acidic under alkaline conditions, i.e. the silica reacts with sodium hydroxide in the form of silicic acid. The sodium ions are combined with silicate ions. Specifically, sodium ions form chemical bonds with oxygen of silicate ions, and the combination of sodium ions and silicate ions enables silicon oxide to be continuously dissolved in sodium hydroxide in the reaction to produce sodium silicate. The reducing pellets are ground into superfine powdery reducing powder, which is beneficial to the dissolution of silicon oxide. Meanwhile, the addition of alkali can be effectively reduced, and the production cost is reduced.
It should be noted that from the two perspectives of silicon and iron extraction, the ultrafine grinding is not only a process for preparing ultrafine iron powder, but also a process for preparing ultrafine silicon extraction raw material. Tests show that the alkali leaching process of the high-silicon tailings belongs to an unreacted nuclear model, and the reaction is gradually carried out from the outside of the particles to the inside. The tailing particles are reduced through superfine grinding, the reaction surface area of the powder is improved, and the leaching rate of silicon is accelerated.
It should be noted that the superfine mill tailings after reduction-magnetic separation have good selectivity in alkaline leaching under normal pressure, and a sodium silicate solution with large molecular weight can be obtained by using a small amount of alkali. Because the silicon oxide generated by adopting the superfine grinding is high in activity, a large amount of active silicon oxide is combined with sodium hydroxide to generate a sodium silicate solution under normal pressure.
In the application, the granularity of the reducing powder ground by the superfine grinding device is required to be 600-900 meshes. Preferably 750-850 mesh. The prior art is fully capable of achieving this feature. The requirement on the granularity is limited, and the grinding energy consumption and the selection of the magnetic separation mode are integrated.
It should be further explained that manufacturers for producing precipitated silica white in industry all adopt fire method to prepare sodium silicate solution. The raw materials for producing sodium silicate are quartz sand and soda ash, and the quartz sand and the soda ash are mixed according to a certain proportion, and then are fed into a reflecting kiln furnace, and are calcined at high temperature (about 1400 ℃) and meltedAnd (5) melting the mixture in a furnace, and then performing water quenching and packaging to obtain the solid sodium silicate. The solid sodium silicate is dissolved into liquid under certain temperature and pressure, and the liquid is the water glass. The chemical reaction formula is as follows: na (Na)2CO3+SiO2→ Na (high temperature)2SiO3+CO2×) @. Compared with the wet method for producing the water glass, the dry method has high energy consumption and high impurity content of sodium silicate, and the white carbon black prepared by the precipitation method has poor quality. The process achieves the purposes of silicon extraction, iron reduction and aluminum reduction through reduction roasting, realizes the granularity refinement of the leaching raw materials through superfine ore grinding, realizes silicon enrichment through magnetic separation-strong magnetic separation, and can prepare a high-quality sodium silicate solution with extremely low impurity content of more than 2.5 by adopting normal-pressure low-temperature low-alkali-consumption leaching, thereby realizing green production.
According to the scheme provided by the application, the targeted high-silicon iron ore has the characteristic of low iron grade, but the embedded granularity of the iron-containing minerals of the high-silicon iron ore is extremely fine. That is, when the iron ore is reduced by heating, the particle size of the reduced iron monomer is very fine. In the prior art, the heating temperature adopted by the scheme of heating direct reduction is higher than 1200 ℃ generally, and the duration time is more than 45 min. The application of the prior art to the process of refining the high-silicon iron ore results in excessive enrichment of the reduced iron monomer in the iron ore, resulting in increased particle size. This can make the milling difficult at a later stage. Therefore, in the scheme of the application, the low-temperature heating scheme is adopted to be 800-1200 ℃, preferably 900-1000 ℃ and more preferably 900-980 ℃ by combining the characteristics of the high-silicon iron ore. And the duration of the low temperature heating schedule is 15-45min, preferably 20-30 min. So as to prevent the particle size of the iron monomer from growing and be beneficial to the grinding and the selection of the subsequent process.
It should be noted that the superfine mill tailings after reduction-magnetic separation have good selectivity of alkaline leaching under normal pressure, only active silicon is leached, and other impurities such as gamma-alumina are not dissolved out.
It needs to be further explained that the requirement of the high-silicon iron ore on the reduction temperature is higher compared with the conventional coal-based direct reduction of the iron ore, and on the basis, the direct reduction process of the coal blending composite pellet in the iron ore is developed. The iron oxide in the high-silicon iron ore is quickly converted into metallic iron by adopting a low-temperature (the high-temperature section is only 900-.
The main chemical reactions of the iron ore coal-based direct reduction comprise the following reactions:
3Fe2O3(s)+C(s)→2Fe3O4(s) + CO (g) formula (1)
3Fe2O3(s)+CO(g)→2Fe3O4(s)+CO2(g) Formula (2)
Fe3O4(s)+CO(g)→3FeO(s)+CO2(g) (T is not less than 843K) formula (3)
FeO(s)+CO(g)→Fe(s)+CO2(g) Formula (4)
C(s)+CO2(g) → 2CO (g) formula (5)
2FeO(s)+SiO2(s)→2FeO·SiO2(s) formula (6)
1/2(2FeO·SiO2)(s)+CO(s)→Fe(s)+1/2SiO2(s)+CO2(g) Formula (7)
The method needs to be further explained that the separation degree of the gangue and iron is improved after the iron particles are pre-enriched, the gangue mainly takes SiO2 as a main component, the crystallinity is greatly reduced after roasting, the activity is high, the grindability is good, and the energy consumption is reduced; meanwhile, the plasticity of the metallic iron is strong, so that the whole ore grinding time is short, and the ore grinding energy consumption is low. The metal iron particles obtained by the reduction system are fine, so that the superfine iron powder can be obtained only by dissociating iron particle monomers in the ore grinding process.
In the traditional scheme, the granularity of silicon oxide in slag is too large. In order to make the silicon oxide be melted into the alkali solution as quickly as possible, the addition amount of the alkali solution is often increased.
In the application, the alkali liquor is added in the step 4) for leaching, and the amount of the alkali liquor is that the pH value of the mixed solution is kept alkalescent. I.e. without the need for excessive addition of lye. This is because in step 3), the particle size of the reducing powder is controlled within the range of 600-900 mesh by adopting an ultra-fine grinding method. Preferably 750-850 mesh. Thus, the silicon oxide can be completely dissolved with the addition of a small amount of lye. And controlling the mode of adding a small amount of alkali liquor, namely controlling the pH value of the solution in the round. Therefore, the addition amount of the alkali liquor is controlled by controlling the pH value of the solution.
It should be noted that, as shown in the figure, the main gangue component in the high silica iron ore is SiO2In the reduction roasting temperature range of the process, SiO2The crystallinity is greatly reduced and is converted into amorphous SiO2And the activity is high, and favorable conditions are created for subsequent alkali leaching of silicon. Meanwhile, the reduction roasting is carried out within the temperature range of the process, the quartz phase can generate second-level phase change from alpha-quartz to beta-quartz and beta-quartz2-tridymite transformation and finally gradual transformation into α -tridymite during cooling. From the thermodynamic analysis, it is found that the crystal form of alpha-quartz is compared with that of crystalline alpha-quartz in the raw ore (Gibbs free energy-87.84 kJ. mol.)-1) Alpha-tridymite (-174.29 kJ. mol)-1) And amorphous SiO2(-210.92kJ·mol-1) The thermodynamic condition of the reaction with NaOH is more excellent, and the leaching of silicon is effectively promoted.
In the application, a sodium silicate solution with a high modulus and a high silica-sodium ratio can be obtained by adopting a countercurrent leaching mode. The high-silicon tailings contain a small amount of ferrous oxide, gamma-alumina and activated carbon. Ferrous oxide is insoluble in alkali and enters the filter residue during leaching. The gamma-alumina has extremely strong water absorption performance, and the internal structure of the gamma-alumina is a porous structure, so that a certain adsorption and filtration effect can be achieved. In addition, the active carbon is also of a porous structure and has a filtering effect. Therefore, when a countercurrent leaching mode is adopted, the reaction from the first layer of alkaline leaching unit to the third layer of alkaline leaching unit not only has the function of fully reacting silicon oxide with sodium hydroxide; because a small amount of gamma-alumina and activated carbon exist in the high-silicon tailings, a higher filtering and adsorbing effect can be achieved in the countercurrent leaching process, and the modulus of the finally obtained sodium silicate solution is high.
It should be noted that the modulus of the ratio of sodium to silica is the amount of leached silicon compared to the amount of sodium added to the alkaline solution. Can reduce the use of alkali liquor.
It is noted that the silica product for preparing the white carbon black is rapidly leached at 90-105 ℃ for 40-120min under normal pressure, and porous particles such as active carbon and the like in the tailings can adsorb Na2O.Al2O3.1.7SiO2.nH2O (n is less than or equal to 2) and silica gel and the like. The product performance is improved through the processes of sedimentation, filtration, dehydration, drying, purity and the like in the process.
It should be further explained that, from the perspective of recovering silicon element, the reduction roasting process is a process of extracting silicon, reducing iron and reducing aluminum, and can obtain high-quality sodium silicate solution, thereby creating favorable conditions for the subsequent preparation of white carbon black. The reduction roasting is a process for converting iron oxide into metallic iron and is used for converting the substance with the largest content of crystalline SiO2Conversion to amorphous SiO2The process of (1). Thermodynamically with Fe2O3Compared with the prior art, the thermodynamic condition of the reaction of the metallic iron and the alkali liquor is poorer, so that the iron element in the tailings after roasting-magnetic separation is less prone to entering the silicon extracting solution. Because the aluminum oxide contained in the iron ore raw ore is mainly alpha-Al2O3And alpha-Al2O3The activity is very strong, the alkali liquor is easy to react with NaOH to consume and enter the silicon extracting solution, and the aluminum element belongs to toxic elements in the white carbon black product, so that the preparation of the white carbon black is not favorable. As can be seen from the thermodynamic phase diagram analysis, when the calcination temperature is raised to 930-2O3Gradually converts into gamma-Al which is not easy to react with alkali liquor2O3. Meanwhile, SiO is separated out from mullite in the temperature range2Thereby further improving the silicon extraction rate.
The alumina-related chemical reaction is as follows:
α-Al2O3→γ-Al2O3formula (8)
Al2O3·2SiO2→γ-Al2O3+2SiO2Formula (9)
Therefore, the purposes of silicon extraction, iron reduction and aluminum reduction of the iron ore are realized through reduction roasting, and good conditions are created for producing high-quality silicon extraction liquid.
In this application, the features of the process themselves are combined. In the first scheme, the sintering flue gas discharged in the step 2) is introduced into the superfine grinding device in the step 3) to prevent iron oxidation. Because the sintering flue gas mainly contains N2、CO2Because of excessive C during pelletizing, CO may also be present in the sintering flue gas. That is to say the sintering fume is a neutral or reducing gas. The neutral or reducing gas can prevent the high-temperature iron powder from contacting oxygen to be oxidized in the superfine grinding process.
In the second scheme, the sintering flue gas discharged in the step 2) is firstly introduced into a first drying device to dry the pellets, and then introduced into the superfine grinding device in the step 3) to prevent iron oxidation. The sintering flue gas is used as the center or the physicochemical property of the reducing gas, and the sintering flue gas is used for drying and preheating the pellets in the first drying device by utilizing the characteristic of high temperature of the sintering flue gas. The energy can be effectively utilized, and the resource waste is reduced.
It needs to be further explained that the superfine iron powder is produced by adopting a superfine grinding mode, the grinding is either dry grinding or wet grinding, and the rotary kiln smoke is used as protective atmosphere in the grinding process.
In the application, a second drying device is further arranged and used for drying the magnetically-separated reduced iron powder, and the purified flue gas is used as a medium for drying and passivating the superfine iron powder, so that the effects of comprehensive utilization of resources and process optimization are achieved.
In the application, after the high-silicon tailings are leached by alkali liquor, sodium silicate solution and filter residues are obtained. The filter residue contains colloid generated by aluminum oxide when being subjected to alkali, and has certain viscosity. The filter residue is used as a binder for pelletizing, so that the use of extra binders can be reduced, and the production cost is reduced.
In the application, the sintering flue gas and the alkaline leaching solution in the step 4) are utilized for heat exchange, so that the temperature of the alkaline solution can be increased, the reaction of silicon oxide and the alkaline solution is accelerated, and the alkaline leaching rate is increased.
It needs to be added to explain that the scheme provided by the application realizes zero discharge of industrial three wastes. The process changes industrial three wastes (waste water, waste gas and waste solids) into valuable, combines the advantages and characteristics of the process, and realizes zero discharge of industrial production. Wherein, the main substances in the wastewater are additives required by the reduction system, so the wastewater is returned to the pelletizing system for utilization; the waste gas is used as a passivation gas for drying pellets, leaching heat supply, a white carbon black precipitator, an iron powder grinding protective atmosphere and drying iron powder after heat exchange and purification treatment; the waste solids comprise two parts of middlings and leached filter residues, wherein the middlings are low-iron carbon-containing residues and can be used as qualified cement raw materials. The filter residue can be used as a binder to return to the batching system for full use. Therefore, the whole process realizes zero discharge of industrial three wastes.
The scheme provided by the application realizes 100% utilization of energy. The process with the highest energy consumption of the whole process is a direct reduction system, the heat taken away by the flue gas of the system accounts for 20-40% of the total heat, and the part of heat is not well utilized in other direct reduction processes, even is directly discharged and lost. The process uses the part of heat for drying green pellets in sequence, supplies low-temperature leaching after heat exchange, uses the residual heat for other purposes in a plant area, and realizes 100% utilization of energy.
The scheme provided by the application has the advantages of low production cost and high product quality. The process has wide raw material source and low cost; the process is simple, and the equipment cost is low; the product is high-quality superfine iron powder and high-quality ultrapure white carbon black, and has larger profit margin.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the technical scheme provided by the application, the reduced iron powder with ultra-fine particle size is directly reduced by short-time low-temperature heating, so that the energy consumption in the roasting process is reduced;
2. according to the technical scheme provided by the application, the produced reduced iron powder is superfine in granularity, so that crushing and grinding can be facilitated, and the energy consumption of grinding is reduced;
3. according to the technical scheme provided by the application, the purified flue gas is used for drying the reduced iron powder and the passivated iron powder particles, and waste heat is utilized, so that energy is saved;
4. according to the technical scheme provided by the application, the sintering flue gas is used as the protective gas in the ore grinding process, so that the quality of the reduced iron powder produced by superfine grinding is favorably ensured;
5. according to the technical scheme provided by the application, the direct reduction technology of low-temperature heating can ensure that the alpha-quartz of the high-silicon iron ore is converted into the alpha-tridymite, so that the leaching of silicon is facilitated;
6. according to the technical scheme provided by the application, the reducing pellets are treated by adopting an ultra-fine grinding technology, so that ultra-fine reduced iron powder can be obtained, and the leaching rate of later-stage silicon can be increased;
7. according to the technical scheme provided by the application, the scheme of leaching sodium silicate with alkali liquor is adopted, so that the energy consumption is reduced;
8. the technical scheme provided by the application realizes zero emission of industrial three wastes, achieves the aim of recycling 100% of energy, reduces the generation cost and improves the product quality.
Drawings
FIG. 1 is a schematic flow chart of the process for producing high-quality sodium silicate using high-silicon iron ore according to the present invention;
FIG. 2 is a detailed overall flow chart of the process for producing high-quality sodium silicate using high-silicon iron ore according to the present invention;
FIG. 3 is a diagram of the polytype transition of SiO 2;
FIG. 4 is a thermodynamic absorption and desorption thermogram of an iron ore reduction system;
fig. 5 is a diagram for analyzing thermodynamic CO consumption of the iron ore reduction system.
Detailed Description
According to the embodiment of the invention, the process for producing high-quality sodium silicate by adopting high-silicon iron ore comprises the following steps:
a process for producing high-quality sodium silicate by adopting high-silicon iron ores comprises the following steps:
1) preparing a reducing material: the high-silicon iron ore is made into pellets to be sintered.
2) Reducing the pellets to be sintered: and heating the pellets to be sintered at high temperature to obtain the reduced pellets.
3) Crushing and grinding to obtain high-silicon tailings: crushing the reduction pellets to obtain reduced crushed materials, grinding the reduced crushed materials by using an ultra-fine grinding device to obtain reduced powder, and magnetically separating the reduced powder to obtain high-silicon tailings.
4) Extracting a sodium silicate solution: and adding alkali liquor into the high-silicon tailings to obtain a solid-liquid mixture, and leaching the sodium silicate solution.
Preferably, the discharge granularity of the superfine grinding device in the step 3) is 600-900 meshes. Preferably 750-850 mesh.
Preferably, the temperature of the low-temperature heating in the step 2) is 800-1200 ℃, preferably 900-1000 ℃, and more preferably 900-980 ℃.
Preferably, the time for low-temperature heating in the step 2) is 15-45min, preferably 20-30 min.
Preferably, the sodium silicate solution leached in step 4) is weakly alkaline.
Preferably, in the step 4), the sodium silicate solution is leached from the high-silicon tailings by adopting a counter-current leaching method. The method comprises the following steps.
4a) Forward alkaline leaching of high-silicon tailings: and the high-silicon tailings subjected to alkaline leaching in the first layer of alkaline leaching unit enter a second layer of alkaline leaching unit for alkaline leaching. And the high-silicon tailings subjected to alkaline leaching in the second-layer alkaline leaching unit enter a third-layer alkaline leaching unit for alkaline leaching.
4b) Reverse discharge of leaching solution: and adding alkali liquor into the third layer of alkaline leaching unit, adding the third layer of leaching solution into the second layer of alkaline leaching unit, adding the second layer of leaching solution into the first layer of alkaline leaching unit, and introducing the leaching solution of the first layer of alkaline leaching unit into a sodium silicate storage container.
4c) Keeping alkalescence: and (3) supplementing alkali liquor to the first layer of alkali leaching unit and the second layer of alkali leaching unit, and keeping the pH value of the solution of the first layer of alkali leaching unit and the second layer of alkali leaching unit to be 7-9, preferably 7.5-8.5.
Preferably, the step 1) comprises the following steps:
1a) crushing the iron ore to obtain iron ore crushed materials, and crushing the internal blending coal to obtain internal blending coal crushed materials.
1b) The iron ore crushed aggregates and the internal blending coal crushed aggregates are mixed and ground under the action of a binder to obtain the pellet raw material.
1c) Pelletizing raw materials are made into pellets in a pelletizing device.
1d) And (3) drying the pellets: and drying and preheating the pellets in a first drying device to obtain the pellets to be sintered.
Preferably, the sintering flue gas discharged in the step 2) is introduced into the superfine grinding device in the step 3) to prevent iron from being oxidized.
Preferably, the sintering flue gas discharged in the step 2) is firstly introduced into a first drying device to dry the pellets, and then introduced into the superfine grinding device in the step 3) to prevent iron oxidation.
Preferably, the filter residue left after the alkaline leaching in the step 4) is used as a binder to participate in the preparation process of the pellets to be sintered in the step 1).
Preferably, the sintering flue gas generated in the step 2) exchanges heat with the solid-liquid mixture in the step 4).
Example 1
According to the embodiment of the invention, the process for producing high-quality sodium silicate by adopting high-silicon iron ore comprises the following steps:
a process for producing high-quality sodium silicate by adopting high-silicon iron ores comprises the following steps:
1) preparing a reducing material: the high-silicon iron ore is made into pellets to be sintered.
2) Reducing the pellets to be sintered: and heating the pellets to be sintered at high temperature to obtain the reduced pellets.
3) Crushing and grinding to obtain high-silicon tailings: crushing the reduction pellets to obtain reduced crushed materials, grinding the reduced crushed materials by using an ultra-fine grinding device to obtain reduced powder, and magnetically separating the reduced powder to obtain high-silicon tailings.
4) Extracting a sodium silicate solution: and adding alkali liquor into the high-silicon tailings to obtain a solid-liquid mixture, and leaching the sodium silicate solution.
Example 2
Example 1 was repeated except that the discharge particle size of the ultrafine grinding apparatus in step 3) was 800 mesh.
Example 3
Example 2 was repeated, except that the temperature of the low-temperature heating in step 2) was 950 ℃.
Example 4
Example 3 was repeated except that the time for the low temperature heating in step 2) was 25 min.
Example 5
Example 4 was repeated except that the sodium silicate solution leached in step 4) was weakly alkaline.
Example 6
Example 5 was repeated except that in step 4), the sodium silicate solution was leached from the high silica tailings using a counter current leaching process. The method comprises the following steps.
4a) Forward alkaline leaching of high-silicon tailings: and the high-silicon tailings subjected to alkaline leaching in the first layer of alkaline leaching unit enter a second layer of alkaline leaching unit for alkaline leaching. And the high-silicon tailings subjected to alkaline leaching in the second-layer alkaline leaching unit enter a third-layer alkaline leaching unit for alkaline leaching.
4b) Reverse discharge of leaching solution: and adding alkali liquor into the third layer of alkaline leaching unit, adding the third layer of leaching solution into the second layer of alkaline leaching unit, adding the second layer of leaching solution into the first layer of alkaline leaching unit, and introducing the leaching solution of the first layer of alkaline leaching unit into a sodium silicate storage container.
4c) Keeping alkalescence: and (3) supplementing alkali liquor to the first layer of alkali leaching unit and the second layer of alkali leaching unit, and keeping the pH values of the solutions of the first layer of alkali leaching unit and the second layer of alkali leaching unit to be 7.5.
Example 6
Example 5 was repeated except that in step 1), the following steps were included:
1a) crushing the iron ore to obtain iron ore crushed materials, and crushing the internal blending coal to obtain internal blending coal crushed materials.
1b) The iron ore crushed aggregates and the internal blending coal crushed aggregates are mixed and ground under the action of a binder to obtain the pellet raw material.
1c) Pelletizing raw materials are made into pellets in a pelletizing device.
1d) And (3) drying the pellets: and drying and preheating the pellets in a first drying device to obtain the pellets to be sintered.
Example 7
Example 6 was repeated except that the sintering flue gas discharged in step 2) was passed through the ultrafine grinding apparatus in step 3) to prevent iron oxidation.
Example 8
Example 6 is repeated, except that the sintering flue gas discharged in step 2) is firstly introduced into the first drying device to dry the pellets, and then introduced into the superfine grinding device in step 3) to prevent iron oxidation.
Example 9
Example 8 is repeated except that the filter residue remaining after the alkaline leaching in step 4) is used as a binder to participate in the preparation process of the pellets to be sintered in step 1).
Example 10
Example 9 was repeated except that the sintering flue gas generated in step 2) was heat exchanged with the solid-liquid mixture in step 4).
Claims (17)
1. A process for producing high-quality sodium silicate by adopting high-silicon iron ore is characterized by comprising the following steps:
1) preparing a reducing material: preparing high-silicon iron ore into pellets to be sintered;
2) reducing the pellets to be sintered: heating the pellets to be sintered at high temperature to obtain reduced pellets;
3) crushing and grinding to obtain high-silicon tailings: crushing the reduction pellets to obtain reduced crushed materials, grinding the reduced crushed materials by using an ultra-fine grinding device to obtain reduced powder, and magnetically separating the reduced powder to obtain high-silicon tailings;
4) extracting a sodium silicate solution: adding alkali liquor into the high-silicon tailings to obtain a solid-liquid mixture, and leaching a sodium silicate solution;
the temperature for high-temperature heating in the step 2) is 900-980 ℃; the discharge granularity of the superfine grinding device in the step 3) is 600-900 meshes.
2. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 1, wherein the discharge granularity of the ultra-fine grinding device in the step 3) is 750-850 meshes.
3. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 1, wherein the time for high-temperature heating in the step 2) is 15-45 min.
4. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 1, wherein the time for high-temperature heating in the step 2) is 20-30 min.
5. A process for producing high-quality sodium silicate using high-silicon iron ore according to any one of claims 1 to 4, wherein the sodium silicate solution leached in step 4) is weakly alkaline.
6. A process for producing high-quality sodium silicate by using high-silicon iron ore according to any one of claims 1 to 4, wherein in the step 4), the sodium silicate solution is leached from the high-silicon tailings by a counter-current leaching method; wherein, the method comprises the following steps;
4a) forward alkaline leaching of high-silicon tailings: the high-silicon tailings after alkaline leaching in the first layer of alkaline leaching unit enter a second layer of alkaline leaching unit for alkaline leaching; the high-silicon tailings after the alkaline leaching of the second layer of alkaline leaching unit enter a third layer of alkaline leaching unit for alkaline leaching;
4b) reverse discharge of leaching solution: adding alkali liquor into the third layer of alkaline leaching unit, adding the third layer of leaching solution into the second layer of alkaline leaching unit, adding the second layer of leaching solution into the first layer of alkaline leaching unit, and introducing the leaching solution of the first layer of alkaline leaching unit into a sodium silicate storage container;
4c) keeping alkalescence: and (3) supplementing alkali liquor to the first layer of alkali leaching unit and the second layer of alkali leaching unit, and keeping the pH values of the solutions of the first layer of alkali leaching unit and the second layer of alkali leaching unit to be 7-9.
7. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 5, wherein in the step 4), the sodium silicate solution is leached from the high-silicon tailings by a counter-current leaching method; wherein, the method comprises the following steps;
4a) forward alkaline leaching of high-silicon tailings: the high-silicon tailings after alkaline leaching in the first layer of alkaline leaching unit enter a second layer of alkaline leaching unit for alkaline leaching; the high-silicon tailings after the alkaline leaching of the second layer of alkaline leaching unit enter a third layer of alkaline leaching unit for alkaline leaching;
4b) reverse discharge of leaching solution: adding alkali liquor into the third layer of alkaline leaching unit, adding the third layer of leaching solution into the second layer of alkaline leaching unit, adding the second layer of leaching solution into the first layer of alkaline leaching unit, and introducing the leaching solution of the first layer of alkaline leaching unit into a sodium silicate storage container;
4c) keeping alkalescence: and (3) supplementing alkali liquor to the first layer of alkali leaching unit and the second layer of alkali leaching unit, and keeping the pH values of the solutions of the first layer of alkali leaching unit and the second layer of alkali leaching unit to be 7-9.
8. The process for producing high-quality sodium silicate according to claim 6, wherein the pH values of the solutions in the first and second alkaline leaching units are maintained at 7.5-8.5.
9. The process for producing high-quality sodium silicate using high-silicon iron ore according to claim 7, wherein the pH values of the solutions in the first and second alkaline leaching units are maintained at 7.5 to 8.5.
10. A process for producing high-quality sodium silicate by using high-silicon iron ore according to any one of claims 1 to 4 and 7 to 9, wherein the step 1) comprises the following steps:
1a) crushing iron ore to obtain crushed iron ore, and crushing internal coal blending to obtain crushed internal coal blending;
1b) mixing and grinding the iron ore crushed aggregates and the internal mixed coal crushed aggregates under the action of a binder to obtain a pellet raw material;
1c) pelletizing raw materials into pellets in a pelletizing device;
1d) and (3) drying the pellets: and drying and preheating the pellets in a first drying device to obtain the pellets to be sintered.
11. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 5, wherein the step 1) comprises the following steps:
1a) crushing iron ore to obtain crushed iron ore, and crushing internal coal blending to obtain crushed internal coal blending;
1b) mixing and grinding the iron ore crushed aggregates and the internal mixed coal crushed aggregates under the action of a binder to obtain a pellet raw material;
1c) pelletizing raw materials into pellets in a pelletizing device;
1d) and (3) drying the pellets: and drying and preheating the pellets in a first drying device to obtain the pellets to be sintered.
12. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 10, wherein the sintering flue gas discharged in the step 2) is introduced into the superfine grinding device in the step 3) to prevent iron from being oxidized; or
And (3) introducing the sintering flue gas discharged in the step 2) into a first drying device to dry the pellets, and introducing into the superfine grinding device in the step 3) to prevent iron oxidation.
13. The process for producing high-quality sodium silicate by using high-silicon iron ores according to claim 5, wherein the sintering flue gas discharged in the step 2) is introduced into the superfine grinding device in the step 3) to prevent iron from being oxidized; or
And (3) introducing the sintering flue gas discharged in the step 2) into a first drying device to dry the pellets, and introducing into the superfine grinding device in the step 3) to prevent iron oxidation.
14. The process for producing high-quality sodium silicate by using high-silicon iron ore according to any one of claims 1 to 4, 7 to 9 and 11 to 13, wherein the filter residue left after alkaline leaching in the step 4) is used as a binder to participate in the process of preparing the pellets to be sintered in the step 1).
15. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 5, wherein the filter residue left after alkaline leaching in the step 4) is used as a binder to participate in the process of preparing the pellets to be sintered in the step 1).
16. A process for producing high-quality sodium silicate by using high-silicon iron ore according to any one of claims 1 to 4, 7 to 9, 11 to 13 and 15, wherein the sintering flue gas generated in the step 2) exchanges heat with the solid-liquid mixture in the step 4).
17. The process for producing high-quality sodium silicate by using high-silicon iron ore according to claim 5, wherein the sintering flue gas generated in the step 2) exchanges heat with the solid-liquid mixture in the step 4).
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| GB191304403A (en) * | 1912-02-21 | 1914-02-19 | Philipp Schneider | Improved Process of Producing from Silicates containing Potash, Products which are Richer in Potassium Oxide. |
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| GB191304403A (en) * | 1912-02-21 | 1914-02-19 | Philipp Schneider | Improved Process of Producing from Silicates containing Potash, Products which are Richer in Potassium Oxide. |
| CN103754885A (en) * | 2014-01-26 | 2014-04-30 | 乌鲁木齐金石徽龙矿业有限公司 | Method for preparing porous silicon dioxide in acid leaching way |
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