Method for measuring specific gravity of converter slag

Abstract

The invention discloses a method for measuring the specific gravity of converter slag, relates to a steelmaking technology, and aims to ignore the influence of the slag blocking effect caused by the specific gravity change of the converter slag in the prior art. Comprising the following steps: extracting converter slag from a converter, cooling to obtain a test sample, weighing the test sample by using an electronic scale with the accuracy of 0.1 g, measuring the volume by using a measuring cylinder containing distilled water, and finally calculating the specific gravity of the test sample. The method has the advantages that the slag proportions of the converter under different conditions are obtained by weighing the converter slag with different slag alkalinity and measuring the volume, and data support is provided for reasonably selecting the converter slag stopping plug and improving the slag stopping qualification rate. The method is simple, convenient and applicable to operation, has few risk factors to people, can quickly measure the specific gravity of various slag of the converter to guide production, and can flexibly call more than two slag stopping plugs on the premise of ensuring the tapping time to reduce the occurrence of slag tapping times.

Description

Technical Field

[0001] The invention relates to steelmaking technology, in particular to a method for measuring the specific gravity of converter slag. Background Art

[0002] In the slag blocking stage of converter steelmaking, commonly used slag blocking technologies include slag blocking balls, slag blocking plugs, and slide plate slag blocking (infrared slag blocking technology). The best of these is the slide plate slag blocking, but the configuration cost and maintenance cost are very high, so it is not the most cost-effective option.

[0003] The technology of the present invention is based on a slag plug, and its principle is to use the specific gravity of the slag plug to be greater than the specific gravity of converter slag but less than the specific gravity of liquid molten steel. At the end of steel tapping, the slag plug is suspended between molten steel and converter slag. After the steel flows out, the slag plug just covers the steel tapping, thereby blocking the converter slag and preventing it from flowing into the molten steel tank.

[0004] At present, the slag-making materials used in steelmaking are adjusted according to the silicon and phosphorus content of molten iron and the converter conditions, and the CaO%, SiO2%, MgO%, and FeO% in the converter slag vary with the final composition of each furnace of steel. When the FeO% content in the converter slag increases significantly due to overoxidation of the molten steel, the specific gravity of the converter slag of this furnace of steel needs to be increased. For example, when smelting XGL steel for wire drawing, since the final carbon is lower than 0.06%, the FeO% content of the converter slag reaches more than 13%, resulting in a higher specific gravity of the converter slag for smelting XGL steel than that for smelting HRB series steel. If the slag blocking effect is poor, it is easy to cause high oxygen in the incoming molten steel or poor deoxidation effect, and the steel is changed to Q195, which seriously affects the steel grade hit rate and processing cost.

[0005] At present, steelmaking enterprises have not measured and counted the specific gravity of converter slag, and the selection of slag plugs is entirely based on experience. Therefore, detecting the specific gravity of converter slag of different steel grades, thereby guiding the reasonable selection of slag plugs, can effectively improve the slag blocking qualification rate, and have a certain role in promoting steel grade selection and reducing alloy costs.

[0006] About converter: converter is a kind of equipment used for metal smelting, especially key equipment commonly used in steelmaking process. It is generally a cylindrical oxygen blowing steelmaking container that can be tilted. The furnace body is cylindrical and mounted on a horizontal axis frame and can rotate. It uses the blown air, pure oxygen or pure oxygen plus fuel oil (or natural gas, water vapor, carbon dioxide) to oxidize impurities in liquid metal and generate the required heat energy. The converter body includes a furnace shell and a refractory lining inside the furnace shell. The furnace shell is welded with steel plates, and the furnace lining includes three parts: working layer, permanent layer and filling layer. The furnace shell consists of three parts: furnace cap, furnace body and furnace bottom. Each part is processed and formed with steel plates, welded and connected with pins to form a whole.

[0007] The working principle of converter steelmaking is mainly based on the physical heat of the molten iron itself and the heat generated by the chemical reaction between the components of the molten iron. In the converter, oxygen is blown into the high-temperature molten iron to cause oxidation reactions with carbon, silicon, manganese, phosphorus and other elements in the molten iron, thereby removing impurity elements and improving the purity and quality of the molten steel. At the same time, the heat generated during these oxidation reactions can maintain the temperature required for steelmaking.

[0008] About converter slag: Converter slag, also known as steel slag, is a kind of waste slag produced in the converter steelmaking process. It mainly comes from oxides formed by oxidation of elements contained in molten iron and scrap steel, impurities brought in by metal charge, added slag-making agents (such as limestone, fluorite, silica), oxidants, desulfurization products and corroded furnace lining materials. The chemical composition of converter slag is very complex, mainly composed of iron oxide (FeO, Fe2O3, Fe3O4), silicon oxide (SiO2), calcium oxide (CaO), etc. Among them, iron oxide is the main component of converter slag, accounting for more than 50% of the total mass. In addition, converter slag also contains impurities and trace elements such as manganese, copper, tin, antimony, and lead. Summary of the invention

[0009] The present invention aims to provide a method for measuring the specific gravity of converter slag, so as to solve the problem that the prior art lacks attention to the specific gravity of converter slag.

[0010] The method for measuring the specific gravity of converter slag described in the present invention comprises the following steps: extracting converter slag from a converter and cooling it to obtain a test sample, weighing the test sample using an electronic scale with an accuracy of 0.1g, then measuring the volume using a measuring cylinder filled with distilled water, and finally calculating the specific gravity of the test sample.

[0011] The method for measuring the specific gravity of converter slag described in the present invention has the advantages that the specific gravity of converter slag under different conditions is obtained by weighing converter slag with different slag basicities and measuring the volume, providing data support for the reasonable selection of converter slag stopper and improving the qualified rate of slag stopper. The operation is simple, convenient and applicable, with few dangerous factors for people. The specific gravity of various types of converter slag can be quickly measured to guide production. Under the premise of ensuring the length of steelmaking time, more than two types of slag stoppers can be flexibly called to reduce the occurrence of slag furnaces. DETAILED DESCRIPTION

[0012] The method for measuring the specific gravity of converter slag described in the present invention firstly overcomes the technical prejudice in the industry that the specific gravity of converter slag does not pay attention to the effect of the slag stopper, and secondly proposes the following specific operations:

[0013] The converter slag is extracted from the converter and cooled to obtain a test sample, the test sample is weighed using an electronic scale with an accuracy of 0.1 g, and then the volume is measured using a measuring cylinder filled with distilled water, and finally the specific gravity of the test sample is calculated.

[0014] Take out the test sample from the measuring cylinder and air dry it, seal it and then conduct component analysis. Fill in the results of the component analysis and the corresponding specific gravity into the statistical table. After repeated several times, the relationship between the influence of each component ratio on the specific gravity is obtained. In the subsequent production batches of each type of steel, the composition of the slag is predicted, and a suitable slag stopper is selected according to the statistical table to ensure that the slag stopper can be effectively suspended between the molten steel and the converter slag.

[0015] The composition analysis includes at least C, O, TFe, MgO, Al2O3, CaO, FeO, MnO, SiO2, P2O5 and TiO2. The statistical table also includes the end point temperature and date of the corresponding furnace.

[0016] Since December 2023, we have started to measure the specific gravity of converter slag, and obtained the specific gravity of converter slag at different contents, so as to select different slag plugs, reduce the number of slag furnaces at the end of steelmaking and reduce costs. When there is carbon steelmaking at the end (end carbon ≥ 0.06%), when the Fe0 content in the slag is 12% lower, the slag does not foam, and the specific gravity of converter slag is often ≥ 3.3g / cm3. This is also the case with actual verification. The specific gravity of converter slag made since December is as follows:

[0017] Furnace No. Weight g <![CDATA[Volume cm 3 > <![CDATA[Density g / cm 3 > date 23213669 212.2 59 3.5966 December 8 23114296 156.7 47 3.3340 December 8 23114297 178.2 52 3.4269 December 8 23213811 144.3 43 3.3658 December 11 23213988 199.5 60 3.3250 December 15 23213949 248.3 74 3.3554 December 14 23213863 136.9 40 3.4225 December 12 23213906 181.9 55 3.3073 December 13 23213864 166.3 48 3.4646 December 12 24100111 150.2 42 3.5762 January 3 24100112 133.1 39 3.4128 January 3 24100220 138.3 40 3.4575 January 5 24100268 121.5 34 3.5735 January 6 24100301 117.5 35 3.3571 January 7 24100548 101 28 3.6071 January 13 24100161 138.7 41 3.3829 January 4 24100445 141.7 41 3.4561 January 10 24100295 81.9 23 3.5609 January 7 24100190 149.4 43 3.4345 January 5 24100142 139.2 41 3.3951 January 4

[0018] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for measuring the specific gravity of converter slag, characterized in that: The following steps are involved: The converter slag is extracted from the converter and cooled to obtain a test sample, the test sample is weighed using an electronic scale, the volume is measured, and finally the specific gravity of the test sample is calculated.

2. A method for measuring the specific gravity of converter slag according to claim 1, characterized in that: The electronic scale has an accuracy of 0.1 g.

3. The method for measuring the specific gravity of converter slag according to claim 1, characterized in that: Volume measurements were made using graduated cylinders.

4. A method for measuring the specific gravity of converter slag according to claim 3, characterized in that: The volume change of the measuring cylinder is obtained by filling it with distilled water.

5. A method for measuring specific gravity of converter slag according to claim 1, characterized in that: The test sample is taken out from the measuring cylinder and air-dried, and then sealed for component analysis; the results of the component analysis and the corresponding specific gravity are filled in the statistical table; after repeated multiple times, the relationship between the influence of the proportion of each component on the specific gravity is obtained; in subsequent production batches of each type of steel, the composition of the slag is predicted, and a suitable slag stopper is selected according to the statistical table to ensure that the slag stopper can be effectively suspended between the molten steel and the converter slag.

6. A method for measuring specific gravity of converter slag according to claim 5, characterized in that: The composition analysis includes at least C, O, TFe, MgO, Al2O3, CaO, FeO, MnO, SiO2, P2O5 and TiO2.

7. A method for measuring specific gravity of converter slag according to claim 5, characterized in that: The statistical table also includes statistics on the end point temperature and date of the corresponding furnace.