Two-step method for efficiently separating iron and phosphorus from high-phosphorus iron-containing resource based on gas-based energy
阅读说明：本技术 基于气基能源的两步法高磷含铁资源铁磷高效分离的方法 (Two-step method for efficiently separating iron and phosphorus from high-phosphorus iron-containing resource based on gas-based energy ) 是由 王静松 王广 薛庆国 郭占成 左海滨 佘雪峰 于 2020-06-03 设计创作，主要内容包括：本发明公开了一种基于气基能源的两步法高磷含铁资源铁磷高效分离的方法,属于炼铁和资源综合利用领域。该方法包括：将高磷含铁资源、渗碳剂、熔剂、粘结剂按预定配比添加并混匀,加适量水分润湿,再次混匀后压制成具有一定抗压强度的团块；团块经烘干后,装入竖炉进行气基还原,还原气体来自于天然气与还原炉尾气重整,制得金属化团块；将金属化团块排出,直接热装入熔分炉,以天然气为燃料进行快速熔分,经水淬和磁选,生产出固态粒状生铁和玻璃渣。本发明原料适应性强、操作简单、可控性强、反应速度快、生产效率高、脱磷效率高、易于实现自动化。(The invention discloses a two-step method for efficiently separating iron and phosphorus from a high-phosphorus iron-containing resource based on gas-based energy, and belongs to the field of iron making and comprehensive utilization of resources. The method comprises the following steps: adding the high-phosphorus iron-containing resource, the carburizing agent, the flux and the binder according to a predetermined proportion, uniformly mixing, adding a proper amount of water for wetting, uniformly mixing again, and pressing into a briquette with a certain compressive strength; after drying, the briquettes are put into a shaft furnace for gas-based reduction, and reducing gas is obtained by reforming natural gas and tail gas of a reducing furnace to prepare metallized briquettes; discharging the metallized lumps, directly hot-charging into a melting furnace, carrying out rapid melting by taking natural gas as fuel, and producing solid granular pig iron and glass slag by water quenching and magnetic separation. The method has the advantages of strong adaptability of raw materials, simple operation, strong controllability, high reaction speed, high production efficiency, high dephosphorization efficiency and easy realization of automation.)
1. A method for efficiently separating iron and phosphorus from a high-phosphorus iron-containing resource by a two-step method based on gas-based energy is characterized by comprising the following steps of:
step 1: adding the high-phosphorus iron-containing resource, the carburizing agent, the flux and the binder according to a predetermined proportion, uniformly mixing, adding a proper amount of water for wetting, uniformly mixing again, and pressing into a briquette with a certain compressive strength;
step 2: after drying, the briquettes are put into a shaft furnace for gas-based reduction, and reducing gas is obtained by reforming natural gas and tail gas of a reducing furnace to prepare metallized briquettes;
and step 3: discharging the metallized lumps, directly hot-charging into a melting furnace, carrying out rapid melting by taking natural gas as fuel, and producing solid granular pig iron and glass slag by water quenching and magnetic separation.
2. The method of claim 1, wherein in step 1, the briquette has a compressive strength of greater than 200N/briquette.
3. The method of claim 1, wherein in step 2, the reducing gas has a composition of H2/CO>1.0。
4. The method of claim 1, wherein in step 1, the high-phosphorus iron-containing resource has a total iron content of 30-70%, a phosphorus content of 0.1-1.5%, and a particle size of less than 1 mm.
5. The method as claimed in claim 1, wherein in the step 3, the gas-based melting furnace adopts a natural gas burner to rapidly heat the metallized briquette so as to rapidly melt the slag iron, and the melted liquid pig iron or semi-steel and slag are rapidly discharged into a water tank to be water-quenched; the melting temperature is 1450-1600 ℃, and the melting time is less than 10 min.
6. The method according to claim 1, wherein in step 1, the carburizing agent is anthracite or coke powder, wherein the fixed carbon content is about 80%, the ash content is below 15%, and the particle size is less than 1 mm.
7. The method of claim 1, wherein in step 1, the fluxing agent is limestone and technical grade sodium carbonate with a particle size of less than 1 mm.
8. The method according to claim 1, wherein in the step 1, the alkalinity of the briquette is controlled to be 1.0-1.6, the internal carburizer accounts for 0-2% of the weight of the iron-containing material, and the sodium carbonate accounts for 0-3% of the weight of the iron-containing material.
9. The method according to claim 1, wherein in the step 2, the degree of terminal reduction of the metallized briquette is 85 to 95%, and the terminal gas phase carburization amount of the metallized briquette is controlled to 2 to 3%.
10. The method of claim 1, wherein the solid granular raw iron phosphorus content is 0.05-0.1% and meets the steel-making requirements.
Technical Field
The invention belongs to the field of ironmaking and comprehensive utilization of resources, and relates to a method for separating iron and phosphorus in a high-phosphorus iron-containing resource and preparing high-quality steel-making pig iron (or semisteel), which is used for developing and utilizing the high-phosphorus iron-containing resource.
Background
The development of the modern steel industry has been in a long history period, the iron ore is in a deterioration trend along with the consumption of high-grade iron ore resources worldwide, and the silicon, aluminum, phosphorus and burning loss content in the ore is continuously increased. The resource reserves of high-phosphorus iron ore at home and abroad are huge, and the problem of comprehensive utilization of the high-phosphorus iron ore is one of the key research directions in the fields of mining industry and metallurgy discipline. Phosphorus impairs the brittleness of the steel, which is particularly pronounced at low temperatures (colloquially referred to as "cold embrittlement"), and must be reduced to reasonable levels. Generally, the phosphorus content in iron ore is less than 0.2%, and the phosphorus content in steel-making pig iron is less than 0.1%. The core of the rational utilization of the high-phosphorus iron ore lies in how to economically and effectively realize iron-phosphorus separation and improve iron grade, thereby obtaining ores meeting the iron making requirement of a blast furnace or clean iron sources meeting the steel making requirement. In order to solve the problems, many researchers at home and abroad explore in many aspects, and generally, two ideas exist: firstly, the ore is pretreated to remove phosphorus before entering the furnace, such as ore dressing, wet leaching, direct reduction-separation and other methods, and qualified iron ore concentrate is obtained for iron-making production; and secondly, removing phosphorus by adopting targeted treatment in smelting, such as molten iron dephosphorization in advance.
The physical beneficiation method mainly realizes the enrichment of iron element and the removal of phosphorus element to a certain extent by means of the difference of physical properties of iron mineral and gangue impurities, and the common methods include reverse flotation, high-gradient magnetic separation, gravity separation and the like. Although the physical separation method is relatively simple in process, because the mineral embedding granularity in the oolitic hematite is extremely fine and often coexists with oolitic green mud and phosphorus-containing minerals or is mutually wrapped, the problems of low concentrate iron grade, low iron recovery rate, poor phosphorus removal effect and the like generally exist by adopting a conventional physical ore dressing method.
The leaching method for reducing phosphorus mainly comprises a chemical leaching method and a microbial leaching method. The chemical leaching method uses acid media such as sulfuric acid, nitric acid or hydrochloric acid to leach the iron ore, selectively dissolves the phosphate ore in the ore, thereby achieving the purpose of reducing phosphorus. The chemical leaching method can effectively realize the separation of iron and phosphorus elements, but the method has more acid consumption and higher cost, and easily causes the dissolution of iron-containing minerals in the ores to form iron loss; the microbiological method has the advantages of low cost and little environmental pollution, but has longer production period.
In the oolitic high-phosphorus hematite, minerals are tightly wrapped and embedded layer by layer, and are difficult to dissociate from monomers, but after direct reduction roasting, the hematite is gradually reduced into metallic iron, iron particles and gangue are respectively gathered and grow up, the original combination state of iron-containing minerals and gangue minerals is changed, and efficient separation of iron and phosphorus can be realized through a subsequent ore grinding-separation process. In order to obtain high iron concentrate grade, iron recovery rate and phosphorus removal rate, a certain dephosphorization agent needs to be added in the reduction process. The direct reduction-magnetic separation method for treating oolitic hematite is superior to the various methods in terms of product iron grade, recovery rate and dephosphorization effect, but a series of technical and economic problems still exist if the method is put into industrial application, such as partial phosphorus still remains in the product, high production cost, high dephosphorization agent consumption and the like.
The influence of reduction melting of high-phosphorus iron ore carbon-containing pellets on dephosphorization is researched and investigated, based on the reduction melting characteristics of the iron ore carbon-containing pellets and the selective reduction characteristics of phosphorus and iron minerals, the product is the iron beads with similar properties to blast furnace pig iron, and the phosphorus content in iron is improved by slag system alkalinity and fluxes (sodium carbonate, fluorite and the like), so that the alkalinity is favorable for reducing the phosphorus content in the iron beads. Meanwhile, no mature reduction melting equipment exists, so that the process is difficult to realize industrial production. The research also adopts the gas reduction-electric furnace melting separation technology to treat the high-phosphorus iron ore to realize the iron-phosphorus separation, and the phosphorus ore is returned in the solid stateThe original stage can not be reduced, and phosphorus and gangue are removed through slag iron melting in the melting stage, so that high-quality pig iron is obtained. Research shows that high phosphorus ore is directly reduced and treated with CO and H at 800 deg.c2Reducing the ore powder for 2H, adding CaO at 1600 ℃ for melting separation for 30min, and finally melting and separating the CO reduced ore sample to obtain an iron sample containing 0.27% of phosphorus, H2And melting and separating the reduced ore sample to obtain an iron sample containing 0.33 percent of phosphorus. The process is more reasonable than coal-based reduction melting in principle, but the melting and separating process of the reduced ore is the key point for controlling phosphorus in iron, and because the smelting period of an electric furnace is relatively long, slag-gold reaction is more sufficient, and part of phosphorus in the slag is reduced, the molten iron or semisteel with low phosphorus content is difficult to obtain.
When the phosphorus content in the molten iron is high, the molten iron must be removed through pretreatment. The common pretreatment equipment comprises a ladle (or torpedo tank car) and a special dephosphorization converter. The common dephosphorization slag system comprises a soda system and a lime system, wherein the soda can obviously reduce the phosphorus content, and the molten iron containing less than 0.1 percent of phosphorus can be obtained. The converter dephosphorization iron water temperature is reduced, pre-desiliconization is not needed, powder spraying is not needed, the process equipment is simple and reliable, the slag quantity is small, the obtained dephosphorization slag contains high phosphorus and has good fertilizer efficiency on crops, but synchronous desulfurization cannot be carried out in the process, the production efficiency is reduced, and the equipment investment is high; the investment of dephosphorization equipment in the foundry ladle and the torpedo ladle is relatively low, dephosphorization and desulfurization can be simultaneously carried out, adverse effects on steel-making production are avoided, but the method has the defects of large slag quantity, high temperature drop, environmental pollution caused by waste slag, incapability of being used as fertilizer and the like. In addition, the molten iron pretreatment dephosphorization process in actual production can only treat low-phosphorus molten iron with the phosphorus content of about 0.10 percent, has certain difficulty in dephosphorization of high-phosphorus molten iron, and adopts a double-slag method for molten iron with medium-high phosphorus content, so that the process has high technical difficulty and high production cost.
Although great progress is made in various aspects of phosphorus reduction of iron ores worldwide, a plurality of problems exist in general, and the requirements of high dephosphorization rate, high metal recovery rate and high iron-containing grade of concentrate products are difficult to meet at the same time; the raw material adaptability, investment cost, technical complexity, production efficiency and the like of different processes also limit the industrial application thereof. Particularly, for areas with rich oil and gas resources, rich high-phosphorus and iron-containing resources and high environmental requirements, no proper and mature high-phosphorus and iron-containing resource utilization technology exists.
Disclosure of Invention
The invention aims to find a technically feasible, economically reasonable and industrialized gas-based energy-based high-phosphorus iron-containing resource comprehensive utilization method, and a low-grade high-phosphorus iron-containing resource gas-based energy clean comprehensive utilization process is opened, so that the existing low-grade iron ore resources are fully utilized, and the sustainable development requirement of the steel industry is met. The invention takes natural gas as a reducing agent (after reforming) and heats fuel in the reduction-melting process, compared with the process taking coal as the reducing agent and energy, the invention can clean and prepare low-phosphorus pig iron (or semisteel) and reduce the emission of gas pollutants and carbon; compared with the coal-based reduction of high-phosphorus iron ore, the reduction temperature of the invention is low, so that the reduction of phosphorus minerals in iron-containing resources can be obviously inhibited, and the phosphorus content in pig iron (or semisteel) can be reduced in principle; compared with the existing high-phosphorus iron ore gas-based reduction, the method controls the gas-phase carburization of the metallic iron and the internal solid carburizing agent in the reduction process, thereby providing an important basis for further realizing iron-phosphorus separation through high-temperature rapid slag iron melting; different from the existing electric energy-based high-phosphorus iron ore melting utilization process, the invention realizes the rapid melting of the metal melting furnace material by using the melting furnace taking natural gas as energy source so as to further complete the iron-phosphorus separation and the metal product quality improvement, and the energy consumption is lower; the liquid metal and slag water quenching process is an important measure for ensuring that the contact reaction time of slag and metal is reduced so as to reduce the phosphorus content in pig iron (or semisteel), and is also an important guarantee that the melting separation process of the metallized furnace burden can be rapidly and smoothly carried out. The comprehensive analysis of the advantages of the whole process of the invention shows that compared with the existing utilization technology of high-phosphorus iron-containing resources, the method is easier to realize industrialization, has lower carbon and is more environment-friendly, and is particularly suitable for popularization and application in areas with rich oil and gas resources, high-phosphorus iron-containing resources and high environmental requirements.
According to the technical scheme of the invention, a two-step method for efficiently separating iron and phosphorus from a high-phosphorus iron-containing resource based on gas-based energy is provided, wherein the method comprises the following steps:
step 1: adding the high-phosphorus iron-containing resource, the carburizing agent, the flux and the binder according to a predetermined proportion, uniformly mixing, adding a proper amount of water for wetting, uniformly mixing again, and pressing into a briquette with a certain compressive strength;
step 2: after drying, the briquettes are put into a shaft furnace for gas-based reduction, and reducing gas is obtained by reforming natural gas and tail gas of a reducing furnace to prepare metallized briquettes;
and step 3: discharging the metallized lumps, directly hot-charging into a melting furnace, carrying out rapid melting by taking natural gas as fuel, and producing solid granular pig iron and glass slag by water quenching and magnetic separation.
Further, in step 1, the compression strength of the briquette is more than 200N/briquette.
Further, in step 2, the reducing gas has a composition of H2/CO>1.0。
Further, in the step 1, the total iron content of the high-phosphorus iron-containing resource is 30-70%, the phosphorus content is 0.1-1.5%, and the granularity is less than 1 mm.
Further, in the step 3, the gas-based melting furnace adopts a natural gas burner to rapidly heat the metallized briquette so as to realize rapid melting of the slag iron, and the melted liquid pig iron or semisteel and the molten slag are rapidly discharged into a water tank for water quenching.
Further, in the step 3, the melting temperature is 1450-1600 ℃, and the melting time is less than 10 min.
Furthermore, the carburizing agent is anthracite or coke powder, wherein the fixed carbon content is about 80%, the ash content is below 15%, and the granularity is less than 1 mm.
Furthermore, the fusing agent is limestone and industrial grade sodium carbonate, and the granularity is less than 1 mm.
Further, the alkalinity of the briquette is controlled to be 1.0-1.6, the internal carburizer accounts for 0-2% of the weight of the iron-containing material, and the sodium carbonate accounts for 0-3% of the weight of the iron-containing material;
furthermore, the end point reduction degree of the metallized briquette is 85-95%, and the end point gas phase carburization amount of the metallized briquette is controlled to be 2-3%.
Furthermore, the phosphorus content of the obtained solid granular pig iron (or semisteel) is 0.05-0.1 percent, and the requirement of steel making is met.
The technical scheme of the invention has the beneficial effects that:
the method has the advantages of strong raw material adaptability, simple operation, strong controllability, high reaction speed, high production efficiency, high dephosphorization efficiency and easy realization of automation, and in addition, natural gas is used as a reducing agent and energy in the slag iron melting process, so the method has less pollutant emission and is environment-friendly. The pre-reduction technology, namely the gas-based shaft furnace direct reduction technology, is the leading-edge technology in the field of iron making, and has a good development trend at home and abroad.
Drawings
FIG. 1 shows the principle flow of the process of the present invention.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.
The terms "first," "second," and the like in the description and in the claims of the present disclosure are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the disclosure described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein.
Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
A plurality, including two or more.
And/or, it should be understood that, for the term "and/or" as used in this disclosure, it is merely one type of association that describes an associated object, meaning that three types of relationships may exist. For example, a and/or B, may represent: a exists alone, A and B exist simultaneously, and B exists alone.
The invention takes a gas-based reduction shaft furnace and a gas-based melting furnace as main equipment, and auxiliary equipment comprises a feeding system, a storage bin, an electronic belt scale, a mixer, a pelletizer, a dryer, a discharging machine, a belt conveying device and an airtight high-temperature chain plate type ore feeder. The specific production process is as follows:
the raw material conditions are as follows:
the total iron content of the high-phosphorus iron-containing resource is 30-70%, the P content is 0.1-1.5%, and the granularity of more than 100% is less than 1 mm.
The carburizing agent is anthracite or coke powder, wherein the fixed carbon content is about 80%, the ash content is below 15%, and the granularity reaches more than 100% and is less than 1 mm.
The flux is limestone and industrial grade sodium carbonate, and the granularity reaches more than 100 percent and is less than 1 mm.
The main production process flow is as follows:
(1) adding the high-phosphorus iron-containing resource, the carburizing agent, the flux and the binder according to a predetermined proportion, adding a proper amount of water for wetting, uniformly mixing again, and pressing into a briquette with higher compressive strength;
(2) drying the briquettes, and then loading the briquettes into a shaft furnace for gas-based reduction, wherein the reducing gas is obtained by reforming natural gas to prepare metallized briquettes;
(3) the metallized lumps are discharged, directly hot-charged into gas furnace, quickly molten, water-quenched and magnetically separated to obtain solid granular pig iron (or semisteel) as raw material for smelting steel and glass dregs as raw material for cement.