阅读说明：本技术 一种引流砂中三氧化二铬含量的测定方法 (Method for measuring content of chromium sesquioxide in drainage sand ) 是由 李金花 卞玉涵 于 2020-04-26 设计创作，主要内容包括：本发明涉及一种引流砂中三氧化二铬含量的测定方法,包括以下步骤：准备试剂阶段,试液获取阶段,称取0.1000g试样于250ml锥形瓶中,加入20ml水、10ml硫酸和10ml磷酸,轻摇,并放到电热板上加热,煮沸1min,再加入2ml硝酸,去除碳化物,发硫酸烟至半瓶,取下冷却,加50ml水溶盐；再用中速滤纸将试液过滤到500ml容量瓶中,定容,摇匀备用；标准溶液配制阶段,分别从量取1.00mL、3.00mL、5.00mL、7.00mLCr储备溶液至4个加有10mL水的锥形瓶中,分别加入2ml硫酸和2ml磷酸,发硫酸烟,取下稍冷,定容至100mL容量瓶中摇匀；测定阶段,将试液和标准溶液同时进行测定。(The invention relates to a method for measuring the content of chromium sesquioxide in drainage sand, which comprises the following steps: a reagent preparation stage and a test solution acquisition stage, wherein 0.1000g of a sample is weighed in a 250ml conical flask, 20ml of water, 10ml of sulfuric acid and 10ml of phosphoric acid are added, the mixture is lightly shaken and placed on an electric heating plate to be heated, the boiling is carried out for 1min, 2ml of nitric acid is added, carbides are removed, sulfuric acid fume is added into a half bottle, the half bottle is taken down and cooled, and 50ml of water-soluble salt is added; then filtering the test solution into a 500ml volumetric flask by using medium-speed filter paper, fixing the volume, and shaking up for later use; in the standard solution preparation stage, 1.00mL, 3.00mL, 5.00mL and 7.00mL of LCr stock solutions are respectively measured into 4 conical flasks with 10mL of water, 2mL of sulfuric acid and 2mL of phosphoric acid are respectively added, sulfuric acid fume is generated, the flasks are taken down and cooled slightly, and the volume is determined to be 100mL and shaken uniformly; and a measuring stage, wherein the test solution and the standard solution are measured simultaneously.)

1. A method for measuring the content of chromium sesquioxide in drainage sand is characterized by comprising the following steps:

in the reagent preparation stage, 1000 mu g/ml of Cr element standard stock solution is measured, sulfuric acid, phosphoric acid and nitric acid reagents are prepared, and then the experimental water of deionized water is prepared;

a test solution obtaining stage, weighing 0.1000g of sample in a 250ml conical flask, adding 20ml of water, 10ml of sulfuric acid and 10ml of phosphoric acid, slightly shaking, placing on an electric hot plate for heating, boiling for 1min, adding 2ml of nitric acid, removing carbide, adding sulfuric acid fume to a half bottle, taking down, cooling, and adding 50ml of water-soluble salt; then filtering the test solution into a 500ml volumetric flask by using medium-speed filter paper, fixing the volume, and shaking up for later use;

in the standard solution preparation stage, 1.00mL, 3.00mL, 5.00mL and 7.00mL of LCr stock solutions are respectively measured into 4 conical flasks with 10mL of water, 2mL of sulfuric acid and 2mL of phosphoric acid are respectively added, sulfuric acid fume is generated, the flasks are taken down and cooled slightly, and the volume is determined to be 100mL and shaken uniformly;

and in the measurement stage, the working parameters of the inductively coupled plasma atomic emission spectrometer are adjusted, and the test solution and the standard solution are measured simultaneously.

2. The method for determining chromium oxide in drainage sand according to claim 1, wherein the operating parameters of the inductively coupled plasma atomic emission spectrometer are power 1300W, plasma gas flow rate 15L/min, atomizer flow rate 0.8L/min, sample injection amount 1.5mL/min and light source stabilization time 20 s.

3. The method for measuring chromium oxide in drainage sand according to claim 1, wherein the number of repeated detections by the inductively coupled plasma atomic emission spectrometer is at least 2.

Technical Field

The invention belongs to the technical field of chemical detection, and particularly relates to a method for determining the content of chromium sesquioxide in drainage sand.

Background

The drainage sand is an indispensable refractory material for tapping of the eccentric furnace, and is a bottom material for tapping of a ladle. The drainage sand for ladle drainage has four basic conditions: the drainage sand is in a high-temperature state at a ladle nozzle for a long time, and the refractoriness of a sintering layer is required to be high; after filling the drainage sand into the water gap, the drainage sand is directly contacted with molten steel, and the initial sintering temperature is not easy to be too high; in the using process, the drainage sand bears larger ferrostatic pressure, so that the drainage sand is required to have very good fluidity and the friction force among particles is as small as possible in order to prevent material stretching; the drainage sand is in a high-temperature state, so that the drainage sand is prevented from automatically falling or being incapable of effectively supporting upper materials in the using process. Based on the requirements, the satisfied practical application comprises four types of common drainage sands: forsterite, siliceous, zircon and chromite drainage sands.

Composition w of chromite (Cr2O 3): 32 to 35 percent; w (FeO): 14 to 17 percent; w (MgO): 12 to 18 percent; w (Al2O 3): 16 to 25 percent; w (SiO 2): 2 to 12 percent. The melting point is about 1730-. In the chrome drainage sand, when the addition amount of the chromite is more than 60 percent, the chromite is in continuous distribution, and the distribution is helpful for forming a continuous sintering layer. At high temperature, iron oxide in chromite reacts and exsolution to form secondary spinel, the volume of a sintering layer changes to generate cracks, so when the sliding plate is opened, unsintered drainage sand at the lower part of the water gap flows out rapidly, the cracks of the sintering layer expand rapidly, and the sintering layer is completely destroyed under the action of static pressure of molten steel, thereby achieving the purpose of automatic boiling.

Disclosure of Invention

The invention aims to provide a method for measuring the content of chromium sesquioxide in drainage sand.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for measuring the content of chromium sesquioxide in drainage sand comprises the following steps:

in the reagent preparation stage, 1000 mu g/ml of Cr element standard stock solution is measured, sulfuric acid, phosphoric acid and nitric acid reagents are prepared, and then the experimental water of deionized water is prepared;

a test solution obtaining stage, weighing 0.1000g of sample in a 250ml conical flask, adding 20ml of water, 10ml of sulfuric acid and 10ml of phosphoric acid, slightly shaking, placing on an electric hot plate for heating, boiling for 1min, adding 2ml of nitric acid, removing carbide, adding sulfuric acid fume to a half bottle, taking down, cooling, and adding 50ml of water-soluble salt; then filtering the test solution into a 500ml volumetric flask by using medium-speed filter paper, fixing the volume, and shaking up for later use;

in the standard solution preparation stage, 1.00mL, 3.00mL, 5.00mL and 7.00mL of LCr stock solutions are respectively measured into 4 conical flasks with 10mL of water, 2mL of sulfuric acid and 2mL of phosphoric acid are respectively added, sulfuric acid fume is generated, the flasks are taken down and cooled slightly, and the volume is determined to be 100mL and shaken uniformly;

and in the measurement stage, the working parameters of the inductively coupled plasma atomic emission spectrometer are adjusted, and the test solution and the standard solution are measured simultaneously.

Specifically, the work parameters of the inductively coupled plasma atomic emission spectrometer are 1300W of power, 15L/min of plasma gas flow, 0.8L/min of atomizer flow, 1.5mL/min of sample injection amount and 20s of light source stabilization time.

Specifically, the repeated detection times of the inductively coupled plasma atomic emission spectrometer are at least 2 times.

The invention has the following beneficial effects: the method can accurately detect the content of the chromium oxide in the drainage sand so as to control the addition amount of the chromite, and has the advantages of high analysis speed, wide dynamic linear range, high sensitivity and the like.

Detailed Description

The present invention will now be described in further detail.

A method for measuring the content of chromium sesquioxide in drainage sand comprises the steps of decomposing a sample by sulfuric acid-phosphoric acid, dissolving salt in water, filtering to remove insoluble substances, selecting an analysis element Cr as an analysis line, measuring the content of chromium in the chromium drainage sand by an inductively coupled plasma atomic emission spectrometry, and finally converting the content into the content of chromium sesquioxide.

Content of the experiment

ICP-AES is also the working parameter of Optima-8000DV inductively coupled plasma atomic emission spectrometer, see Table 1: an acid-etching resistant atomizer and an argon purifier;

TABLE 1 operating parameters of inductively coupled plasma atomic emission spectrometer

Preparation phase, preparing standard stock solution of Cr single element 1000 mug/ml, sulfuric acid: analyzing and purifying; phosphoric acid: analyzing and purifying; nitric acid: analyzing and purifying; the experimental water was deionized water.

And a test solution acquisition stage, weighing 0.1000g (accurate to +/-0.0001 g) of sample in a 250ml conical flask, adding 20ml of water, 10ml of sulfuric acid and 10ml of phosphoric acid, slightly shaking, putting on an electric hot plate for heating, boiling for about 1min, adding 2ml of nitric acid, and removing carbide. The smoke was cooled to half a flask, removed and cooled slightly, and 50ml of water-soluble salt was added. The test solution is filtered into a 500ml volumetric flask by using medium-speed filter paper, the conical flask and the filter paper are washed for several times until no residual ions exist, the volume is fixed, and the solution is shaken up for standby.

And in the standard solution preparation stage, 1.00mL, 3.00mL, 5.00mL and 7.00mL of the stock solution are respectively measured into 4 conical flasks added with 10mL of water, 2mL of sulfuric acid and 2mL of phosphoric acid are respectively added, sulfuric acid fume is generated, the solution is taken down, the volume is fixed to 100mL of a volumetric flask, and the solution is uniformly shaken. The concentrations were 10mg/L, 30mg/L, 50mg/L, and 70mg/L, respectively.

In ICP-AES, because the temperature of plasma is higher, the existing chemical interference is less, and the main existing interference is physical interference and spectral interference. The physical interference can be eliminated by adopting a matrix matching method and an internal standard method, namely, the difference of test data caused by different matrixes is eliminated by adding sulfuric acid and phosphoric acid into a standard solution, and the interference caused by the fluctuation of the sampling amount and the atomization efficiency of an atomizer due to the fluctuation of argon and the fluctuation of conditions such as instrument environment and the like is eliminated by the internal standard method. Spectral interference can be avoided by selecting less interfering spectral lines and selecting appropriate background subtraction points.

And (3) measuring the standard solution series according to the working conditions set by the instrument, and drawing a calibration curve by taking the mass concentration of the Cr element as an abscissa and the emission intensity as an ordinate. The linear range, linear regression equation and correlation coefficient of the calibration curve are shown in table 2.

TABLE 2 calibration Curve-related parameters

Element(s)	Analysis line/nm	Linear range mg/L	Correlation coefficient
				Cr	267.716	10-70	0.9997

The content of chromium in the drainage sand is measured according to a test method, precision investigation is carried out, the result is shown in table 3, and the relative deviation of the measured result is less than 1% as shown in table 3.

TABLE 3 results of precision test

TABLE 4 content of Cr2O 3%

Different samples are respectively compared and analyzed by the method and the GB/T4699.2-2008 chromium content determination standard, and the accuracy meets the requirement. The results are shown in Table 5

The present invention is not limited to the above embodiments, and any structural changes made under the teaching of the present invention shall fall within the scope of the present invention, which is similar or similar to the technical solutions of the present invention.

The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.