阅读说明：本技术 一种超低碱度高强度烧结矿的制造方法 (Manufacturing method of ultralow-alkalinity high-strength sintered ore ) 是由 韩宏松 韩凤光 于 2018-06-25 设计创作，主要内容包括：本发明公开了一种超低碱度高强度烧结矿的制造方法,主要解决现有技术中用高SiO<Sub>2</Sub>含量的铁矿石生产的烧结矿的铁品位低的技术问题。本发明采用的技术方案是,一种超低碱度高强度烧结矿的制造方法,包括：1)配置镁质熔剂；2)配料,按照配比称量烧结所用铁矿石及镁质熔剂,控制烧结矿的二元碱度R<Sub>2</Sub>为1.70-1.80,烧结矿中SiO<Sub>2</Sub>的重量百分含量为5.0-5.7％,MgO的重量百分含量为1.0-1.2％；3)混匀造粒,将一次混匀料转入二次混匀滚筒中进行混匀造粒,造粒后得到的二次混匀料；4)对二次混匀料进行抽风烧结,烧结完成后得到成品烧结矿。本发明实现了用高SiO<Sub>2</Sub>含量的铁矿石生产的高强度烧结矿,效益显著。(The invention discloses a method for manufacturing ultra-low alkalinity high-strength sintered ore, mainly aiming at solving the problem of using high SiO in the prior art 2 The low iron grade of the sinter produced by the content of the iron ore. The invention adopts the technical scheme that the manufacturing method of the ultra-low alkalinity high-strength sintered ore comprises the following steps: 1) preparing a magnesium flux; 2) proportioning, weighing iron ore and magnesium flux, and controlling the binary basicity R of sintered ore 2 1.70-1.80 of SiO in the sintered ore 2 5.0-5.7 wt%, 1.0-1.2 wt% of MgO; 3) uniformly mixing and granulating, namely transferring the primary uniformly mixed material into a secondary uniformly mixing roller for uniformly mixing and granulating to obtain a secondary uniformly mixed material after granulation; 4) and (4) performing air draft sintering on the secondary mixed material, and obtaining a finished sintered ore after sintering. The invention realizes the use of high SiO 2 The high-strength sintered ore produced by the iron ore with the content has obvious benefit.)

1. A manufacturing method of ultra-low alkalinity high-strength sintered ore is characterized by comprising the following steps:

1) preparing a magnesium flux, crushing dolomite by using a ball mill, and controlling the dolomite with the grain size of less than or equal to 3mm to account for more than 75 percent of the total mass of the dolomite; the dolomite comprises CaCO as the component in percentage by weight₃：50-60％，MgCO₃: 40-50%, the balance being unavoidable impurities;

2) proportioning, weighing iron ore and magnesium flux, and controlling the binary basicity R of sintered ore₂1.70-1.80 of SiO in the sintered ore₂5.0-5.7 wt%, 1.0-1.2 wt% of MgO;

3) mixing and granulating, loading the prepared iron ore and magnesium flux into a mixing roller for primary mixing, adding water during the primary mixing process, stirring, obtaining a primary mixed material, and mixing H in the primary mixed material₂The weight percentage of O is 5.9-6.2%; transferring the primary uniformly-mixed material into a secondary uniformly-mixed roller for uniformly mixing and granulating to obtain a secondary uniformly-mixed material;

4) and (4) performing air draft sintering on the secondary mixed material, transferring the secondary mixed material to a sintering trolley for air draft sintering, and obtaining a finished sintered ore after sintering.

2. The method for manufacturing ultra-low alkalinity high-strength sintered ore according to claim 1, wherein the TI strength of the finished sintered ore in the step 4) is not less than 81%.

Technical Field

The invention relates to a method for manufacturing blast furnace ironmaking raw material sinter, in particular to a method for manufacturing ultralow-alkalinity high-strength sinter, belonging to the technical field of ferrous metallurgy sintering.

Background

The sinter is one of the main iron-containing raw materials for blast furnace iron making in China at present, and the high-grade and high-strength sinter is an important raw material technical guarantee for obtaining excellent technical and economic indexes in blast furnace smelting. For several years, with the increasing competition of the steel market and the deterioration of iron ore resources, many steel plants have to use some high SiO₂Iron ore in a content of SiO in the iron ore to reduce cost₂The mass content of the compound is more than or equal to 7 percent.

By using high SiO₂The content of iron ore is used for producing sintered ore, and according to the traditional sintering process, in order to ensure that the sintered ore has good drum strength to meet the smelting requirement of a blast furnace, the binary alkalinity R is generally required₂The control is over 1.95, and is even over 2.0 in many cases, so as to ensure the generation of sufficient bond-phase calcium ferrite; even if the so-called low-alkalinity sintering technology is adopted, the binary alkalinity needs to be controlled to be 1.85 or even more than 1.95, and a large amount of CaO flux still needs to be used, so that the iron grade of the sintered ore is finally low, and the optimization of the technical and economic indexes of the blast furnace is influenced. Theories and practices prove that: the iron grade of the sintered ore entering the blast furnace is reduced by 1 percent, the fuel ratio is increased by 1.5 percent, the yield is reduced by 2.5 percent, the iron slag per ton is increased by 30kg/t, and the coal ratio of the blast furnace is reduced by 15 kg/t.

Disclosure of Invention

The invention aims to provide a method for manufacturing an ultralow-alkalinity high-strength sintered ore, which mainly solves the problem of using high SiO in the prior art₂The invention solves the technical problem that the sintered ore produced by the iron ore has low iron grade, and reduces the production cost of the high-strength sintered ore.

The technical idea of the method is to improve the iron grade of the sinter by reducing the alkalinity of the sinter and improve the SiO in the sinter₂The quality content of the sintered ore is reduced to ensure that the sintered ore has good drum strength, and the production technical requirement of the modern blast furnace is met.

The invention adopts the technical scheme that the manufacturing method of the ultra-low alkalinity high-strength sintered ore comprises the following steps:

1) preparing a magnesium flux, crushing dolomite by using a ball mill, and controlling the dolomite with the grain size of less than or equal to 3mm to account for more than 75 percent of the total mass of the dolomite; the dolomite comprises CaCO as the component in percentage by weight₃：50-60％，MgCO₃: 40-50%, the balance being unavoidable impurities;

2) proportioning, weighing iron ore and magnesium flux, and controlling the binary basicity R of sintered ore₂1.70-1.80 of SiO in the sintered ore₂5.0-5.7 wt%, 1.0-1.2 wt% of MgO;

3) mixing and granulating, loading the prepared iron ore and magnesium flux into a mixing roller for primary mixing, adding water during the primary mixing process, stirring, obtaining a primary mixed material, and mixing H in the primary mixed material₂The weight percentage of O is 5.9-6.2%; transferring the primary uniformly-mixed material into a secondary uniformly-mixed roller for uniformly mixing and granulating to obtain a secondary uniformly-mixed material;

4) and (4) performing air draft sintering on the secondary mixed material, transferring the secondary mixed material to a sintering trolley for air draft sintering, and obtaining a finished sintered ore after sintering.

The binary basicity R of the sinter produced by the process of the invention₂1.70-1.80 of SiO in the sintered ore₂5.0-5.7 wt%, 1.0-1.2 wt% of MgO; TI intensity is more than or equal to 81 percent;

the binary alkalinity R of the sinter of the invention₂Is m_CaO/m_SiO2，m_CaOM is the mass of CaO in the sinter_SiO2For SiO in sinter₂The quality of (c).

The method of the invention is based on the following experimental studies: when sintering SiO in ore blending₂When the content is high, a large amount of 2 FeO. SiO is generated in the sintering process₂Fayalite and calcium fayalite (CaO)_x(FeO)_2-xSiO₂The silicate binder phase is added, which can obviously increase the drum strength of the sinter; on the other hand, when SiO is in ore blending₂At high contents, even if the binary basicity R is controlled to be low₂But, however, doThe absolute content of CaO is not low, so that the other main binding phase of calcium ferrite CaO. Fe is generated in the sintering process₂O₃The generation of the sintered ore can be ensured, which is undoubtedly beneficial to the improvement of the drum strength of the sintered ore; finally, the content of MgO in the sintered ore is controlled to be lower, so that the MgO and the iron oxide can be inhibited from generating magnesium ferrite MgO & Fe₂O₃Thereby affecting the combination of CaO and iron oxide to reduce the generation amount of calcium ferrite, and magnesium ferrite MgO & Fe₂O₃The melting temperature of the sintered ore is higher, and a liquid phase is difficult to generate under the condition of a sintering process, so that the control of the MgO content of the sintered ore is also beneficial to improving the drum strength of the sintered ore. Based on the above research mechanism, high SiO₂The low alkalinity and the low MgO can ensure that the sintering ore has good drum strength on the premise of improving the grade of the sintering ore as much as possible, and the requirement of modern blast furnace smelting is met.

The method controls the granularity of the MgO flux dolomite to be less than 3mm mostly, which is because the method ensures a certain specific surface area of the flux, improves the efficiency of the contact reaction of CaO in the dolomite and iron oxide in the sintering process, improves the generation condition of calcium ferrite, and improves the generation quantity, thereby improving the strength of the sintered ore.

The method of the invention enlarges the high SiO content₂The use ratio of the iron ore in the content is high SiO when producing the sinter₂The mass proportion of the iron ore can reach 10-50%, the produced sinter has high drum strength and grade, and can meet 3000m³The requirement of blast furnace smelting.

The high SiO of the invention₂Iron ore in the content of SiO₂Iron ore with a mass content of more than or equal to 7 percent.

Compared with the prior art, the invention has the following positive effects: 1. the method can effectively improve the iron grade by properly and greatly reducing the alkalinity and MgO in the sintered ore. 2. The method maintains the higher SiO content of the sinter₂The content is favorable for 2FeO SiO₂Fayalite and calcium fayalite (CaO)_x(FeO)_2-xSiO₂And the generation of silicate binder phase improves the drum strength of the sinter. 3. The method of the inventionHigh-holding sintered ore SiO₂Content, i.e. control of lower binary basicity R₂But the absolute content of CaO is not low, so that the other main binding phase of calcium ferrite CaO. Fe is generated in the sintering process₂O₃The formation of (b) can be ensured, which is advantageous for ensuring high drum strength of the sinter. 4. The method of the invention can greatly reduce the MgO content in the sintering ore, reduce the generation of low-strength magnesium ferrite, promote the generation of calcium ferrite, improve the strength of the sintering ore, reduce the alkalinity and SiO₂The reduction of (a) has a negative influence on the strength of the sintered ore. 5. The method realizes the use of high SiO₂Production of high-strength high-grade sinter from iron ore₂The iron ore with the content of more than 7.0 percent is sintered and produced, when the using mass proportion of the iron ore is controlled to be 10-50 percent, the strength and the grade of the sintered ore can also reach higher levels, the requirement of blast furnace smelting is met, the benefit is obvious, the process is simple, and the realization is easy.

Detailed Description

The invention is further described below with reference to specific examples.