阅读说明：本技术 一种冶金尘泥中游离氧化钙的快速检测方法 (Rapid detection method for free calcium oxide in metallurgical dust and mud ) 是由 余志友 王东彦 姜海龙 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种冶金尘泥中游离氧化钙的快速检测方法,包括以下步骤：(1)称取经烘干和均质化搅拌处理的尘泥样品；(2)向所述尘泥样品中加水进行消解,快速搅拌后进行连续测温,并绘制温升ΔT与时间t的曲线,记录温升峰值为特征温升；(3)采用化学法测定尘泥样品中f-CaO的含量,标定所述尘泥样品的特征温升所对应的f-CaO的含量；其中,所述温升ΔT为后续温度测量值与初始温度测量值的差值的绝对值。本发明通过检测消解过程中温升,间接确定尘泥中游离氧化钙含量,使其满足样品准备方便,检测简便,检测费用低,能实现快速检测,适应现场检测的需求。(The invention discloses a method for quickly detecting free calcium oxide in metallurgical dust and sludge, which comprises the following steps: (1) weighing a dust mud sample subjected to drying, homogenizing and stirring treatment; (2) adding water into the dust and mud sample for digestion, quickly stirring, continuously measuring the temperature, drawing a curve of temperature rise delta T and time T, and recording a peak value of the temperature rise as a characteristic temperature rise; (3) measuring the content of f-CaO in a dust and mud sample by a chemical method, and calibrating the content of f-CaO corresponding to the characteristic temperature rise of the dust and mud sample; and the temperature rise delta T is the absolute value of the difference value between the subsequent temperature measurement value and the initial temperature measurement value. The invention indirectly determines the content of free calcium oxide in the dust mud by detecting the temperature rise in the digestion process, so that the invention meets the requirements of convenient sample preparation, simple and convenient detection, low detection cost, quick detection and adaptation to on-site detection.)

1. A method for rapidly detecting free calcium oxide in metallurgical dust and sludge is characterized by comprising the following steps:

(1) weighing a dust mud sample subjected to drying, homogenizing and stirring treatment;

(2) adding water into the dust and mud sample for digestion, quickly stirring, continuously measuring the temperature, drawing a curve of temperature rise delta T and time T, and recording a peak value of the temperature rise as a characteristic temperature rise;

(3) measuring the content of f-CaO in a dust and mud sample by a chemical method, and calibrating the content of f-CaO corresponding to the characteristic temperature rise of the dust and mud sample;

and the temperature rise delta T is the absolute value of the difference value between the subsequent temperature measurement value and the initial temperature measurement value.

2. The method for rapidly detecting the free calcium oxide in the metallurgical dust and sludge according to claim 1, wherein in the step (1), the weighing amount of the dust and sludge sample is 1-2 kg.

3. The method for rapidly detecting the free calcium oxide in the metallurgical dust mud according to claim 1, wherein in the step (2), tap water or tap water subjected to magnetization treatment is adopted as the water; and/or

The addition amount of the water is 9-20 wt% of the dust mud sample; and/or

The device used in the digestion process is a temperature rise detection device for digesting free calcium oxide.

4. The method for rapidly detecting the free calcium oxide in the metallurgical dust mud according to claim 3, wherein in the step (2), the magnetic field intensity is 400 +/-50 mT, and the magnetization time is 44-58 min.

5. The method for rapidly detecting the free calcium oxide in the metallurgical dust mud as claimed in claim 4, wherein in the step (2), the magnetization time is 50 min.

Technical Field

The invention belongs to the field of free calcium oxide digestion, and particularly relates to a rapid detection method for free calcium oxide in metallurgical dust and sludge, which is mainly applied to the digestion of the free calcium oxide in zinc-containing dust and sludge in steel plants treated by coal-based direct reduction processes such as a rotary hearth furnace and the like.

Background

Various solid waste dust and mud can be generated in the production process of a steel mill, a large amount of valuable elements such as iron, carbon, zinc, lead and the like can be recycled, but the elements such as zinc, lead and the like have adverse effects on the process when being directly reused in production lines such as sintering, blast furnaces and the like: such as erosion and nodulation of the furnace lining in the blast furnace, which makes the operation not smooth; therefore, many steel mills currently adopt coal-based direct reduction processes such as rotary hearth furnaces and the like to treat the zinc-containing steel mill dust and sludge; the process mainly comprises two steps of direct reduction of dust mud carbon-blending agglomeration, a rotary hearth furnace and the like. In the carbon-blending agglomeration step, high yield and high strength are basic requirements, but because the dust mud contains undigested free calcium oxide (f-CaO), the carbon-blending dust mud can be broken because the free calcium oxide expands due to reaction with water in the agglomeration process, and the yield and the strength of the ball are reduced. Therefore, it is necessary to digest the free calcium oxide before pelletizing or briquetting the dust and mud. At present, the common methods for digesting the free calcium oxide in the dust and mud comprise the following two methods, one method is to add water to soak the dust and mud, so that the free calcium oxide reacts with the water to produce calcium hydroxide, and then the calcium hydroxide is used for agglomeration; the other method is to mix and stir the dust and mud with high water content and the dust and mud with low water content, and utilize water in the dust and mud with high water content to digest free calcium oxide while reducing the water content of the mixed dust and mud. Regardless of the digestion method, the digestion process needs to be controlled to reduce the free calcium oxide to a certain target value.

In order to improve the yield and strength of the ball blocks, the content of free calcium oxide in the digested dust and mud product needs to be determined frequently and compared with the target content, so that the parameter adjustment amount of the digestion process is determined, and the aim of controlling the digestion process is fulfilled. The content of free calcium oxide in the dust mud is generally determined by a chemical method such as extraction of benzene acid by glycol and dripping; for example, a free calcium oxide determinator disclosed in chinese patent CN 211877777U includes a drop positioning device, a heating and stirring device is disposed below a titration position for heating and sufficiently stirring a solution in a sample bottle, a condenser tube mounting platform is disposed above the titration position for detachably hanging a condenser tube, the bottom of the condenser tube corresponds to the titration position, the titration position is provided with a light source and a color collecting unit, and the color collecting unit is a color sensor or a camera for collecting a color of a sample to be detected; the device measures the content of free calcium oxide by titration of glycol-extracted benzoic acid; the main problems with this assay are as follows: the requirements on sample preparation and measurement environment are high, the measurement time is long, more reagents and instruments are needed, the training amount of detection personnel is large, and the detection cost is high.

In view of the above, there is a need in the art to develop a method for rapidly detecting free calcium in dust and mud, which can meet the requirements of high frequency, rapidness, simplicity, low cost and easy detection in field detection.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for rapidly detecting free calcium oxide in metallurgical dust and mud, which indirectly determines the content of residual free calcium oxide in a dust and mud sample by detecting the temperature rise of the dust and mud sample in the digestion process, so that the method meets the requirements of convenient sample preparation, simple and convenient detection, low detection cost, capability of realizing rapid detection and adaptation to field detection.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for quickly detecting free calcium oxide in metallurgical dust and sludge, which comprises the following steps:

(1) weighing a dust mud sample subjected to drying, homogenizing and stirring treatment;

(2) adding water into the dust and mud sample for digestion, quickly stirring, continuously measuring the temperature, drawing a curve of temperature rise delta T and time T, and recording a peak value of the temperature rise as a characteristic temperature rise;

(3) measuring the content of f-CaO in a dust and mud sample by a chemical method, and calibrating the content of f-CaO corresponding to the characteristic temperature rise of the dust and mud sample;

and the temperature rise delta T is the absolute value of the difference value between the subsequent temperature measurement value and the initial temperature measurement value.

Preferably, in the step (1), the weighed amount of the dust and mud sample is 1-2 kg.

Preferably, in the step (2), the water is tap water or tap water subjected to magnetization treatment;

the addition amount of the water is 9-20 wt% of the dust mud sample; the device used in the digestion process is a temperature rise detection device for digesting free calcium oxide.

Preferably, in the step (2), in the magnetization treatment process, the magnetic field strength is 400 +/-50 mT, and the magnetization time is 44-58 min.

Preferably, in the step (2), the magnetization time is 50 min.

The principle of the rapid detection method of free calcium oxide of the invention is as follows: free calcium oxide in steel mill sludge added with water will generate f-CaO (free calcium oxide) which reacts with water to generate Ca (OH)₂The digestion reaction belongs to an exothermic reaction, the heat release is in direct proportion to the reaction quantity of free calcium oxide, and the maximum temperature rise of the dust mud sample generated by adding water is in positive correlation with the content of the free calcium oxide under the non-adiabatic condition; therefore, under a certain non-adiabatic condition, the characteristic temperature rise (the highest temperature rise in the digestion process) caused by the digestion reaction of a certain amount of dust and mud samples and water is detected, and the f-CaO content corresponding to the characteristic temperature rise value is calibrated (such as by adopting a chemical titration method), so that the f-CaO content in the dust and mud samples can be determined through the characteristic temperature rise detection, the amount of the f-CaO in the detected dust and mud deviating from the target value is further determined, and a quantitative basis is provided for the regulation and control of the digestion process parameters.

The method for rapidly detecting the free calcium oxide in the metallurgical dust and mud provided by the invention has the following beneficial effects:

1. according to the invention, the content of free calcium oxide in the dust mud is indirectly determined by detecting the characteristic temperature rise in the dust mud sample digestion process, so that the dust mud f-CaO detection sample is convenient to prepare, simple and convenient to detect, low in detection cost, capable of realizing rapid detection and suitable for the requirements of on-site detection;

2. compared with free calcium oxide detection methods such as a chemical titration method and the like, the detection time of the rapid detection method for the free calcium oxide in the metallurgical dust mud is generally not more than 4 min;

3. when the method for quickly detecting the free calcium oxide in the metallurgical dust and mud adopts the magnetized water, the detection time does not exceed 2min, and the detection is quick, concise and efficient.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic flow chart of the method for rapidly detecting free calcium oxide in metallurgical dust and sludge according to the present invention;

fig. 2 is a schematic structural diagram of a temperature rise detection device for digesting free calcium oxide in dust and mud in the rapid detection method for free calcium oxide in metallurgical dust and mud of the invention.

Detailed Description

In order to better understand the technical solutions of the present invention, the following further describes the technical solutions of the present invention with reference to the accompanying drawings and examples.

Referring to fig. 1, the invention provides a method for rapidly detecting free calcium oxide in metallurgical dust and sludge, comprising the following steps:

(1) weighing a dust mud sample subjected to drying, homogenizing and stirring treatment;

the specific process is as follows: firstly, a sample to be detected is processed, such as drying and uniform stirring, so that dust and mud to be detected is homogenized, the sampling quantity is representative only when the sampling quantity is large due to the fact that the dust and mud are not uniform, and after multiple tests, the sampling quantity of the dust and mud sample is determined to be 1-2 kg.

(2) Adding water into the dust and mud sample for digestion, quickly stirring, continuously measuring the temperature, drawing a curve of temperature rise delta T and time T, and recording a peak value of the temperature rise as a characteristic temperature rise;

the specific process is as follows: putting a dust mud sample into a temperature rise detection device for digesting free calcium oxide, adding water through a water adding device to form a mixture, rapidly and uniformly stirring under the action of a mixer, starting continuous temperature measurement, drawing a curve of temperature rise delta T and time T by taking the temperature rise delta T (namely the absolute value of the difference value between a subsequent temperature measurement value and an initial temperature measurement value) as a longitudinal axis and temperature measurement time T as a transverse axis, wherein the peak value of the temperature rise is taken as characteristic temperature rise because delta T-T is a single-peak value curve; the water used can be tap water or magnetized water, and the magnetized water is obtained by taking tap water as source water through magnetization treatment. Wherein the magnetic field intensity in the magnetization treatment is 400 +/-50 mT, the magnetization time is 44-58 min, and the preferred magnetization time is 50 min.

(3) Measuring the content of f-CaO in a dust and mud sample by a chemical method, and calibrating the content of f-CaO corresponding to the characteristic temperature rise of the dust and mud sample;

the specific process is as follows: and obtaining a dust and mud sample by adopting the same method and steps, determining the content of f-CaO in the dust and mud sample by a chemical method, such as dripping of glycol-extracted benzoic acid, and the like, calibrating the content of f-CaO corresponding to the characteristic temperature rise of the dust and mud sample, and then taking the calibrated content as the quantity basis for adjusting the digestion process parameters by combining the content of the target f-CaO.

The temperature rise detection device (see fig. 2) for digesting the free calcium oxide in the dust and mud sample in the step (2) comprises a stirring kettle 1, a water feeder 2 and a mixer 3 which are arranged in the stirring kettle 1, a temperature measurement metal sheet 5 which is embedded on the inner wall of the stirring kettle 1 and a temperature measurement instrument 6 which is connected with the temperature measurement metal sheet 5; the stirring kettle 1 is of a box body structure, a containing space is arranged in the stirring kettle 1, a through hole 4 is formed in the side wall of the stirring kettle, and the through hole 4 in the stirring kettle 1 is arranged close to the upper wall of the stirring kettle 1 in order to prevent dust and mud in the stirring kettle 1 from coming out of the through hole 4; the material of the upper wall, the side wall and the bottom wall of the stirring tank 1 may be a metal material or a heat insulating material, and the specific selection may be determined according to the content of free calcium oxide in the dust and mud sample, for example, when the f-CaO content in the dust and mud sample is high (for example, the f-CaO content is greater than 3.0 wt%), the metal material is used, and when the f-CaO content in the dust and mud sample is low (for example, the f-CaO content is less than or equal to 3.0 wt%), the heat insulating material, such as wood or plastic, is used. The water feeder 2 is fixed on the upper wall of the stirring kettle 1 and is used for feeding water into the stirring kettle 1 to clear up dust and mud; the mixer 3 is used for stirring the dust and mud after water is added, and aims to fully mix the dust and mud with water so as to facilitate the digestion of free calcium oxide in the dust and mud; wherein, in order to save the inner space of the reaction kettle, the water feeder 2 and the mixer 3 adopt a coaxial structure (see figure 2). Temperature measurement sheetmetal 5 can inlay on stirred tank 1's lateral wall/diapire, can with dirt mud direct contact, this temperature measurement sheetmetal 5 is the heat conduction material of excelling in, for example copper, aluminium etc. is convenient for the temperature measurement. The temperature measuring instrument 6 is connected with the temperature measuring metal sheet 5, and measures the temperature and the temperature rise (the temperature rise refers to the absolute value of the difference value between the subsequent temperature measurement value and the initial temperature measurement value) in the dust and mud sample digestion process by measuring the temperature of the temperature measuring metal sheet 5; wherein the temperature measuring instrument 6 can adopt an infrared temperature measuring instrument 6.

The method for rapidly detecting free calcium oxide of the invention is further described by combining specific examples; wherein, the temperature rise detection device for digesting the free calcium oxide in the process of digesting the free calcium oxide in the step (2) in the embodiment is shown in figure 2.

Example 1

The dust and mud sample is a mixed digestion dust and mud drying material obtained by mixing and digesting LT ash and OG mud through a material stirring digestion process;

taking 1kg of dust and mud sample, placing the dust and mud sample in a temperature rise detection device for digesting free calcium oxide in dust and mud as shown in figure 2, adding tap water accounting for 12 wt% of the mass of the dust and mud sample, quickly stirring uniformly, then starting to continuously measure temperature, making a curve of absolute value delta T of difference value between a subsequent temperature measurement value and an initial temperature measurement value and time T to obtain a peak value delta T-T_maxThe characteristic temperature rise value of the digested mixed dust and mud is obtained; and then measuring the content of free calcium oxide in the dust and mud sample by adopting a titration method, and establishing a corresponding relation between the characteristic temperature rise value of the mixed dust and mud and the content of the free calcium oxide. And reversely operating, namely determining the content of free calcium oxide in the measured dust mud according to the measured characteristic temperature rise value.

In this example, the characteristic temperature rise value of the dust and mud sample was 3.5 ℃, and the time for the characteristic temperature rise value to appear was 3 min. The corresponding mixed dust had a free calcium oxide content of 1.45 wt%.

Example 2

The dust and mud sample is a mixed digestion dust and mud drying material obtained by mixing and digesting LT ash and OG mud through a material stirring digestion process;

taking 1kg of dust and mud sample, placing the dust and mud sample in a temperature rise detection device for digesting free calcium oxide shown in figure 2, and adding 12 wt% of magnetized water based on the mass of the dust and mud sample, wherein the magnetization parameters are as follows: the magnetization intensity is 400mT, and the magnetization time is 44 min; then, after the mixture is quickly stirred uniformly, continuous temperature measurement is started, the absolute value delta T of the difference value between the subsequent temperature measurement value and the initial temperature measurement value and the time T are used for making a delta T-T curve to obtain a peak value delta T_maxNamely the characteristics of the digestion mixed dust and mudA temperature rising value is proved; and then measuring the content of free calcium oxide in the dust and mud sample by adopting a titration method, and establishing a corresponding relation between the characteristic temperature rise value of the mixed dust and mud and the content of the free calcium oxide. And reversely operating, namely determining the content of free calcium oxide in the dust mud sample according to the measured characteristic temperature rise value.

In this example, the characteristic temperature rise value of the dust and mud sample was 3.9 ℃, and the time for the characteristic temperature rise value to appear was 2.2 min. The corresponding mixed dust had a free calcium oxide content of 1.45 wt%.

Example 3

The dust and mud sample is a mixed digestion dust and mud drying material obtained by mixing and digesting LT ash and OG mud through a material stirring digestion process;

taking 1kg of dust and mud sample, placing the dust and mud sample in a temperature rise detection device for digesting free calcium oxide shown in figure 2, and adding 12 wt% of magnetized water based on the mass of the dust and mud sample, wherein the magnetization parameters are as follows: the magnetization intensity is 400mT, and the magnetization time is 50 min; then, after the mixture is quickly stirred uniformly, continuous temperature measurement is started, the absolute value delta T of the difference value between the subsequent temperature measurement value and the initial temperature measurement value and the time T are used for making a delta T-T curve to obtain a peak value delta T_maxThe characteristic temperature rise value of the digested mixed dust and mud is obtained; and then measuring the content of free calcium oxide in the dust and mud sample by adopting a titration method, and establishing a corresponding relation between the characteristic temperature rise value of the mixed dust and mud and the content of the free calcium oxide. And reversely operating, namely determining the content of free calcium oxide in the dust mud sample according to the measured characteristic temperature rise value.

In this example, the characteristic temperature rise value of the dust and mud sample was 4.5 ℃, and the time for the characteristic temperature rise value to appear was 1.5 min. The corresponding mixed dust had a free calcium oxide content of 1.45 wt%.

Example 4

The dust and mud sample is a mixed digestion dust and mud drying material obtained by mixing and digesting LT ash and OG mud through a material stirring digestion process;

taking 1kg of dust and mud sample, placing the dust and mud sample in a temperature rise detection device for digesting free calcium oxide shown in figure 2, and adding 12 wt% of magnetized water based on the mass of the dust and mud sample, wherein the magnetization parameters are as follows: the magnetization intensity is 400mT, and the magnetization time is 58 min; then get fastAfter the mixture is stirred uniformly, continuous temperature measurement is started, the absolute value delta T of the difference value between the subsequent temperature measurement value and the initial temperature measurement value and the time T are used for making a delta T-T curve to obtain a peak value delta T_maxThe characteristic temperature rise value of the digested mixed dust and mud is obtained; and then measuring the content of free calcium oxide in the dust and mud sample by adopting a titration method, and establishing a corresponding relation between the characteristic temperature rise value of the mixed dust and mud and the content of the free calcium oxide. And reversely operating, namely determining the content of free calcium oxide in the digested mixed dust and mud according to the measured characteristic temperature rise value.

In this example, the characteristic temperature rise value of the dust and mud sample was 4.0 ℃, and the time for the characteristic temperature rise value to appear was 1.9 min. The free calcium oxide content in the corresponding dust-mud sample was 1.45 wt%.

In conclusion, the method indirectly determines the content of free calcium oxide in the dust mud sample by detecting the temperature rise in the sample digestion process, so that the method meets the requirements of convenient sample preparation, simple and convenient detection, low detection cost, capability of realizing rapid detection and adaptation to the requirements of on-site detection; compared with free calcium oxide detection methods such as a chemical titration method and the like, the detection time of the rapid detection method for the free calcium oxide in the dust mud is generally not more than 4 min; when the magnetized water is adopted in the method for rapidly detecting the free calcium oxide, the detection time is not more than 2min, and the detection is rapid, concise and efficient.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that changes and modifications to the above described embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.