CN112945944A - Method for accurately detecting main content of industrial calcium carbonate - Google Patents
Method for accurately detecting main content of industrial calcium carbonate Download PDFInfo
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- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 title claims abstract description 388
- 229910000019 calcium carbonate Inorganic materials 0.000 title claims abstract description 194
- 238000000034 method Methods 0.000 title claims abstract description 53
- 238000001514 detection method Methods 0.000 claims abstract description 29
- 239000003109 Disodium ethylene diamine tetraacetate Substances 0.000 claims abstract description 21
- ZGTMUACCHSMWAC-UHFFFAOYSA-L EDTA disodium salt (anhydrous) Chemical compound [Na+].[Na+].OC(=O)CN(CC([O-])=O)CCN(CC(O)=O)CC([O-])=O ZGTMUACCHSMWAC-UHFFFAOYSA-L 0.000 claims abstract description 21
- 235000019301 disodium ethylene diamine tetraacetate Nutrition 0.000 claims abstract description 21
- 238000005303 weighing Methods 0.000 claims abstract description 13
- 159000000003 magnesium salts Chemical class 0.000 claims abstract description 8
- 239000012266 salt solution Substances 0.000 claims abstract description 6
- 239000000523 sample Substances 0.000 claims description 63
- 239000007788 liquid Substances 0.000 claims description 52
- 239000000243 solution Substances 0.000 claims description 52
- 239000013074 reference sample Substances 0.000 claims description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 37
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 27
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 24
- 238000012360 testing method Methods 0.000 claims description 24
- 239000012086 standard solution Substances 0.000 claims description 19
- 239000011575 calcium Substances 0.000 claims description 15
- 239000012488 sample solution Substances 0.000 claims description 15
- 238000002360 preparation method Methods 0.000 claims description 13
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 12
- 229910052791 calcium Inorganic materials 0.000 claims description 12
- 238000007865 diluting Methods 0.000 claims description 12
- ORFSSYGWXNGVFB-UHFFFAOYSA-N sodium 4-amino-6-[[4-[4-[(8-amino-1-hydroxy-5,7-disulfonaphthalen-2-yl)diazenyl]-3-methoxyphenyl]-2-methoxyphenyl]diazenyl]-5-hydroxynaphthalene-1,3-disulfonic acid Chemical compound COC1=C(C=CC(=C1)C2=CC(=C(C=C2)N=NC3=C(C4=C(C=C3)C(=CC(=C4N)S(=O)(=O)O)S(=O)(=O)O)O)OC)N=NC5=C(C6=C(C=C5)C(=CC(=C6N)S(=O)(=O)O)S(=O)(=O)O)O.[Na+] ORFSSYGWXNGVFB-UHFFFAOYSA-N 0.000 claims description 10
- 238000009736 wetting Methods 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 5
- 239000012153 distilled water Substances 0.000 claims description 3
- 238000010521 absorption reaction Methods 0.000 abstract description 3
- 238000010494 dissociation reaction Methods 0.000 abstract description 3
- 230000005593 dissociations Effects 0.000 abstract description 3
- 238000005259 measurement Methods 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 abstract description 3
- 235000010216 calcium carbonate Nutrition 0.000 description 163
- 238000004448 titration Methods 0.000 description 31
- 150000002500 ions Chemical group 0.000 description 13
- 239000011521 glass Substances 0.000 description 10
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 9
- 229960001484 edetic acid Drugs 0.000 description 9
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 8
- 239000000758 substrate Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 4
- 239000000292 calcium oxide Substances 0.000 description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- 241001062472 Stokellia anisodon Species 0.000 description 2
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- -1 carboxylic acid sodium salt Chemical class 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- PSHMSSXLYVAENJ-UHFFFAOYSA-N dilithium;[oxido(oxoboranyloxy)boranyl]oxy-oxoboranyloxyborinate Chemical compound [Li+].[Li+].O=BOB([O-])OB([O-])OB=O PSHMSSXLYVAENJ-UHFFFAOYSA-N 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012490 blank solution Substances 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000012085 test solution Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/38—Diluting, dispersing or mixing samples
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
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- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Plasma & Fusion (AREA)
- Engineering & Computer Science (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Abstract
The invention provides a method for accurately detecting the main content of industrial calcium carbonate. The method for accurately detecting the main content of the industrial calcium carbonate comprises the following steps: preparing; and (4) calibrating and detecting a sample. The method for accurately detecting the main content of the industrial calcium carbonate adopts the calcium carbonate reference calibration when the disodium ethylene diamine tetraacetate is calibrated, the calcium carbonate is easy to purify, so that the calcium carbonate can react with the disodium ethylene diamine tetraacetate in an equivalent way, the dropping point is easy to determine, and meanwhile, the magnesium salt solution is added, so that the phenomenon of advanced dissociation of the end point color is changed, the end point color change is more sensitive, the detection result is more accurate, furthermore, the fineness of the method is not required to be too fine, the mixture can be detected even to below 35 meshes, the linear range of the calcium carbonate content is not required to be controlled, the detection can be carried out from low content to high content, the sample weighing range of the method is wider and easy to weigh, the sample weighing speed cannot influence the moisture absorption of the sample to be oxidized, and the measurement precision of.
Description
Technical Field
The invention relates to the technical field of methods for detecting the main content of industrial calcium carbonate, in particular to a method for accurately detecting the main content of industrial calcium carbonate.
Background
The present study shows that: industrial calcium carbonate is the main raw material for producing common glass, and natural calcium oxide is the main component of glass and is about 5-15%. Therefore, the main content of the industrial calcium carbonate is particularly important for accurately proportioning raw materials, and particularly in the production of TFT glass substrates, the quality of the glass substrates is directly influenced by the content of calcium oxide, so that accurate and rapid detection of the main content of the industrial calcium carbonate plays a critical role in controlling the quality stability of the glass substrates.
Meanwhile, the standards for detecting calcium carbonate in the prior art are as follows: GB/T19281-2014.
The method for detecting calcium carbonate in the prior art comprises the following steps: 0.60g of a calcium carbonate sample which has been dried to a constant mass in advance at 105 ℃ C. + -. 2 ℃ is weighed to the nearest 0.0002 g. Placing the mixture into a 250mL beaker, and adding a little water (adding a little absolute ethyl alcohol into the active calcium carbonate product) for wetting. Covering the surface dish, dropwise adding a hydrochloric acid solution along the mouth of the cup until the sample is completely dissolved, filtering with medium-speed filter paper, fully washing with water, collecting the filtrate and the washing solution in a 250mL volumetric flask, diluting with water to a scale, and shaking up for later use. Transferring 25.0mL of the solution into a conical flask, adding 5mL of triethanolamine solution, 25mL of water and a small amount of calcium reagent, namely carboxylic acid sodium salt indicator, adjusting the solution to be wine red by using sodium hydroxide solution, adding 0.5mL of the solution in excess, and titrating by using an ethylene diamine tetraacetic acid standard titration solution. And simultaneously performing a blank test.
In the prior art, a zinc oxide-based standard Ethylene Diamine Tetraacetic Acid (EDTA) standard titration solution is adopted in the method for detecting calcium carbonate, and the terminal point can be dissociated in advance, so that the terminal point is insensitive in color and inaccurate in concentration; the calculation result is made more inaccurate. The detection process is complex, the operation is complicated, the time is long, errors are easily generated in a plurality of steps, and the accuracy is low.
Further, in patent No. 201310528843.4, the patent name: a method for detecting the main content of industrial calcium carbonate efficiently, quickly and accurately includes such steps as smelting the analytically pure lithium tetraborate as solvent in platinum crucible at high temp to obtain the sample wafer required by fluorescent instrument, adding high-grade calcium carbonate to smelt a series of standard samples, creating standard working curve, and analyzing the calcium carbonate content of the sample by working curve.
Meanwhile, the method for detecting industrial calcium carbonate in the patent document has certain effect, but in the step of manufacturing the standard curve, the high-grade pure calcium carbonate is placed in a platinum crucible with a cover and is placed in a muffle furnace for firing for 0.5-1.5 hours when the temperature is increased to 450-; and the design range of the percentage content of the calcium carbonate in the standard working curve is 98-99.99%, namely the method only aims at the detection of the main content of the high-content calcium carbonate and cannot be used for the detection of the low content of the calcium carbonate, so that the detection range of the main content of the calcium carbonate by the detection method is limited and cannot be comprehensively popularized and applied.
Therefore, there is an urgent need to redesign a new method for detecting the main content of industrial calcium carbonate to solve the above problems.
Disclosure of Invention
The invention provides a method for accurately detecting the main content of industrial calcium carbonate, which aims to solve the technical problems in the background technology.
The invention provides a method for accurately detecting the main content of industrial calcium carbonate, which comprises the following steps: preparation: weighing 7.45g of disodium ethylene diamine tetraacetate in a 1000ml beaker, adding a small amount of water, heating for dissolving, and diluting to obtain a solution to be labeled; calibration: placing a dry calcium carbonate working reference sample with constant weight in a 250ml volumetric flask, adding a small amount of water for wetting, then adding 10ml of hydrochloric acid to completely dissolve the calcium carbonate working reference sample, diluting the calcium carbonate working reference sample to a scale with water and shaking up to prepare a calcium carbonate sample solution, calibrating the solution to be calibrated prepared in the preparation step by using the sample solution to prepare a standard solution, and recording data; sample detection: placing 25mL of calcium carbonate sample liquid prepared in the calibration step into a 250mL conical flask, sequentially adding 25mL of water, 2mL of 100g/L magnesium salt solution, 10mL of 100g/L sodium hydroxide solution and a little calcium indicator to prepare liquid to be detected, and then dripping the standard solution in the calibration step into the liquid to be detected until the liquid to be detected is pure blue as an end point and does not fade for 30 seconds. At this time, the content of calcium carbonate is calculated according to the corresponding public indication, and meanwhile, a blank test is carried out.
Optionally, in the calibration step, the calcium carbonate working reference sample has a mass of 0.45-0.60 g.
Optionally, in the calibration step, the temperature of the dried calcium carbonate working reference sample is controlled at 105 ℃ to 115 ℃, and the calcium carbonate working reference sample is accurate to 0.0002 g.
Optionally, in the calibration step, the volume ratio of hydrochloric acid is 1: 1.
Optionally, in the calibration step, the shaken calcium carbonate sample liquid is filtered if the shaken calcium carbonate sample liquid is turbid, and the shaken calcium carbonate sample liquid is not turbid, so that the calcium carbonate sample liquid is not required to be filtered.
Alternatively, in the sample detection step, the water added to the 250ml Erlenmeyer flask is distilled water.
Optionally, in the step of preparing, the volume of the prepared solution to be tested is 1000 ml.
Optionally, in the step of detecting the sample, the standard solution in the step of calibration is dripped into the liquid to be detected until the liquid to be detected becomes pure blue as an end point and does not fade for 30 s.
The invention has the following beneficial effects:
the method for accurately detecting the main content of the industrial calcium carbonate comprises the following steps: preparation: weighing 7.45-149 g of disodium ethylene diamine tetraacetate in a 1-20L container, adding a small amount of water, heating for dissolving, and diluting to obtain a solution to be labeled; calibration: placing a dry calcium carbonate working reference sample with constant weight in a 250ml volumetric flask, adding a small amount of water for wetting, then adding 10ml of hydrochloric acid to completely dissolve the calcium carbonate working reference sample, diluting the calcium carbonate working reference sample to a scale with water and shaking up to prepare a calcium carbonate sample solution, calibrating the solution to be calibrated prepared in the preparation step by using the sample solution to prepare a standard solution, and recording data; the method comprises the steps of calibrating disodium ethylene diamine tetraacetate, namely calibrating by using a calcium carbonate reference when the disodium ethylene diamine tetraacetate is calibrated, wherein calcium carbonate is easy to purify and can react with the disodium ethylene diamine tetraacetate in an equivalent manner, and a dropping point is easy to determine.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
As background art, industrial calcium carbonate is the main raw material for glass production, and natural calcium oxide is the main component of glass, and is about 5-15%. Therefore, the main content of the industrial calcium carbonate is particularly important for accurately proportioning raw materials, and particularly in the production of TFT glass substrates, the quality of the glass substrates is directly influenced by the content of calcium oxide, so that accurate and rapid detection of the main content of the industrial calcium carbonate plays a critical role in controlling the quality stability of the glass substrates.
Meanwhile, the standards for detecting calcium carbonate in the prior art are as follows: GB/T19281-2014.
The method for detecting calcium carbonate in the prior art comprises the following steps: 0.60g of a calcium carbonate sample which has been dried to a constant mass in advance at 105 ℃ C. + -. 2 ℃ is weighed to the nearest 0.0002 g. Placing the mixture into a 250mL beaker, and adding a little water (adding a little absolute ethyl alcohol into the active calcium carbonate product) for wetting. Covering the surface dish, dropwise adding a hydrochloric acid solution along the mouth of the cup until the sample is completely dissolved, filtering with medium-speed filter paper, fully washing with water, collecting the filtrate and the washing solution in a 250mL volumetric flask, diluting with water to a scale, and shaking up for later use. Transferring 25.0mL of the solution into a conical flask, adding 5mL of triethanolamine solution, 25mL of water and a small amount of calcium reagent, namely carboxylic acid sodium salt indicator, adjusting the solution to be wine red by using sodium hydroxide solution, adding 0.5mL of the solution in excess, and titrating by using an ethylene diamine tetraacetic acid standard titration solution. And simultaneously performing a blank test.
In the prior art, a zinc oxide-based standard Ethylene Diamine Tetraacetic Acid (EDTA) standard titration solution is adopted in the method for detecting calcium carbonate, and the terminal point can be dissociated in advance, so that the terminal point is insensitive in color and inaccurate in concentration; the calculation result is made more inaccurate. The detection process is complex, the operation is complicated, the time is long, errors are easily generated in a plurality of steps, and the accuracy is low.
Further, in patent No. 201310528843.4, the patent name: a method for detecting the main content of industrial calcium carbonate efficiently, quickly and accurately includes such steps as smelting the analytically pure lithium tetraborate as solvent in platinum crucible at high temp to obtain the sample wafer required by fluorescent instrument, adding high-grade calcium carbonate to smelt a series of standard samples, creating standard working curve, and analyzing the calcium carbonate content of the sample by working curve.
Meanwhile, the method for detecting industrial calcium carbonate in the patent document has certain effect, but in the step of manufacturing the standard curve, the high-grade pure calcium carbonate is placed in a platinum crucible with a cover and is placed in a muffle furnace for firing for 0.5-1.5 hours when the temperature is increased to 450-; and the design range of the percentage content of the calcium carbonate in the standard working curve is 98-99.99%, namely the method only aims at the detection of the main content of the high-content calcium carbonate and cannot be used for the detection of the low content of the calcium carbonate, so that the detection range of the main content of the calcium carbonate by the detection method is limited and cannot be comprehensively popularized and applied.
The method for accurately detecting the main content of the industrial calcium carbonate comprises the following steps:
preparation: 7.45g of disodium ethylene diamine tetraacetate is weighed in a 1000ml beaker, then a small amount of water is added for heating and dissolving, and then dilution is carried out to prepare the liquid to be marked.
In the preparation step, the volume of the prepared solution to be marked is 1L, namely the whole preparation process is to put 7.45g of disodium ethylene diamine tetraacetate into a 1L container, then add water for dilution until the solution in the beaker is filled, namely 1L, so as to finish the preparation of the solution to be marked.
Calibration: placing the dry calcium carbonate working reference sample with constant weight into a 250ml volumetric flask, adding a small amount of water for wetting, then adding 10ml of hydrochloric acid to completely dissolve the calcium carbonate working reference sample, diluting the calcium carbonate working reference sample to a scale with water and shaking up to obtain a calcium carbonate sample solution, and calibrating the solution to be calibrated prepared in the preparation step by using the calcium carbonate sample solution to obtain a standard solution.
Wherein, the main chemical reaction formula of the calcium carbonate sample liquid is as follows:
CaCO3+2HCl═CaCl2+H2O+CO2；
meanwhile, in the calibration step, the mass of the calcium carbonate working reference sample is 0.45-0.60g, the temperature of the dried calcium carbonate working reference sample is controlled at 105-115 ℃, the calcium carbonate working reference sample is accurate to 0.0002g, the volume ratio of hydrochloric acid is 1: 1, and the method specifically comprises the following steps:
weighing 0.45-0.60g of calcium carbonate working reference sample which is dried to constant weight at the temperature of 105-115 ℃, accurately weighing 0.0002g, placing the calcium carbonate working reference sample in a 250mL volumetric flask, then adding a small amount of water to wet the calcium carbonate working reference sample, adding 10mL of hydrochloric acid with the volume ratio of 1: 1 until the calcium carbonate working reference sample in the 250mL volumetric flask is completely dissolved, diluting the calcium carbonate working reference sample to a scale with water, and shaking up to obtain a calcium carbonate sample solution.
The calcium carbonate sample liquid after shaking is turbid, the calcium carbonate sample liquid is not required to be filtered if the calcium carbonate sample liquid after shaking is not turbid, and the accuracy of a standard solution can be improved by filtering the calcium carbonate sample liquid after shaking, so that the test accuracy of the method for accurately detecting the main content of industrial calcium carbonate, disclosed by the invention, on the calcium carbonate content is improved.
Example 1 in step calibration:
0.4562g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the number of milliliters after titration was 22.93ml, thereby giving a standard solution of 0.01988mol/L disodium ethylenediaminetetraacetate concentration.
Example 2in step calibration:
0.4623g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the number of milliliters after titration was 23.22ml, thereby giving a standard solution of 0.01989mol/L disodium ethylenediaminetetraacetate concentration.
Example 3 in step calibration:
0.4505g of a dry constant weight calcium carbonate working reference sample is weighed, wherein the milliliter number after titration is 22.63ml, so that the concentration of the standard solution, namely the disodium ethylene diamine tetraacetate, is 0.01989 mol/L.
Example 4 in step calibration:
0.4768g of dry constant weight calcium carbonate working reference sample is weighed, wherein the milliliter number after titration is 23.97ml, so that the concentration of the standard solution, namely the disodium ethylene diamine tetraacetate, is 0.01987 mol/L.
Example 5 in step calibration:
0.4524g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the number of milliliters after titration was 22.75ml, thereby obtaining a standard solution of 0.01987mol/L disodium ethylenediaminetetraacetate concentration.
Example 6 in step calibration:
0.4896g of dry constant weight calcium carbonate working reference sample is weighed, wherein the milliliter number after titration is 24.60ml, so that the concentration of the standard solution, namely the disodium ethylene diamine tetraacetate, is 0.01988 mol/L.
Further, the average value calculation was performed for example 1 in the step calibration to example 6 in the step calibration, thereby obtaining an average value of the concentration of disodium ethylenediaminetetraacetate of example 6 in example 1 in the step calibration to example 6 in the step calibration of 0.01988 mol/L.
The standard liquid calibration results in the calibration of the steps are as follows:
sample detection: placing 25mL of calcium carbonate sample liquid prepared in the calibration step into a 250mL conical flask, sequentially adding 25mL of water, 2mL of 100g/L magnesium salt solution, 10mL of 100g/L sodium hydroxide solution and a little calcium indicator to prepare liquid to be detected, then dripping the standard liquid in the calibration step into the liquid to be detected until the liquid to be detected is pure blue as an end point and does not fade for 30s, at the moment, calculating the content of calcium carbonate according to corresponding notations, and simultaneously performing a blank test.
Wherein, the formula for calculating the content of the calcium carbonate is as follows:
wherein omega is the mass percent of calcium carbonate;
v is the numerical value of the volume of the standard titration solution of the disodium ethylene diamine tetraacetate consumed by the titration test solution, mL;
v0 is the numerical value of the volume of the titrating solution of the ethylene diamine tetraacetic acid standard brick consumed by titrating the blank solution, mL;
m is the mass g of the weighed calcium carbonate sample;
in the sample detection step, 25ml of distilled water is added into a 250ml conical flask, so that the accuracy of the method for accurately detecting the main content of the industrial calcium carbonate in the determination of the content of the calcium carbonate is ensured.
Further, the specific implementation steps of the sample detection are as follows: placing 25mL of standard solution prepared in the calibration step into a 250mL conical flask, and sequentially adding 25mL of water, 2mL of 100g/L magnesium salt solution, 10mL of 100g/L sodium hydroxide solution and a little calcium indicator to prepare a solution to be detected;
and then, dripping the standard liquid prepared in the calibration step into the liquid to be detected until the liquid to be detected becomes pure blue and does not fade for 30s, and detecting the liquid to be detected so as to obtain the content of the calcium carbonate.
The method comprises the steps of preparing a liquid to be detected, adding a sodium hydroxide solution, titrating the liquid to be detected with a standard solution, and adjusting the pH value of the liquid to be detected to be more than or equal to 12, wherein the sodium hydroxide solution is used for adjusting the acidity in the liquid to be detected to be more than or equal to 12, then adding a calcium indicator, titrating the liquid to be detected with the standard solution to change from wine red to. The discoloration principle is as follows, the ionization of calcium indicator (usually expressed as H2 Ind) in the solution to be tested is performed according to the following formula:
H3Ind═2H++HInd2-
in a solution to be detected with a pH of not less than 12, HINd2-With Ca2+The ions form relatively stable complex ions, and the reaction is as follows:
HInd2-+Ca2+═CaInd-+H+
therefore, the calcium indicator is added into the standard liquid, the solution is wine red, and when the standard liquid is dripped, because the disodium ethylene diamine tetraacetate and the Ca are dripped2+Ion formation ratio CaInd-Complex ion CAY with more stable complex ion2-Thus, near the end point of titration, CaInd-The complex ion is continuously converted into more stable CAY2-The complex ion, and the calcium indicator is liberated at this time, the reaction can be expressed as follows:
CaInd-+H2Y2-═CAY2-+HInd2-+H2O；
since CAY 2-ion is colorless, the end point is that the solution to be detected changes from wine red to pure blue when reaching the end point, and the solution does not fade for 30S.
Of course, in order to improve the determination of the calcium carbonate content by the method for accurately detecting the main content of industrial calcium carbonate, when the liquor to be detected is changed from wine red to pure blue, the liquor to be detected is changed to pure blue, and the liquor does not fade for 30S.
The method is used for detecting the main content of industrial calcium carbonate, and in the step of sample detection, when the pH of the detection solution of the adjusting belt is more than or equal to 12, Mg2+The ions will form Mg (OH)2Precipitation, i.e. Mg2+Coexistence of ions, small amount of Mg coexisting2+The ions not only do not interfere with the determination of calcium, but also cause an end point ratio of Ca2+The presence of ions alone is more acute. When Mg2+Ions and Ca2+When ions coexist, the reaction end point is changed from wine red to pure blue, and when Ca exists2+When ions exist alone, the liquor to be detected is changed from wine red to violet blue, so that Ca existing alone is measured2+When ionic, small amounts of Mg are often added2+An ionic solution.
It is worth noting that when the solution to be detected is titrated to the end point, the blue color returns to the purple color again, which is called end point returning. The phenomenon is caused by suspended particles of calcium and magnesium salts, the accuracy of determination is influenced, and when the situation exists, hydrochloric acid can be added to acidify the liquid to be detected, so that the alkalinity can be removed, and then NaOH is used for neutralizing the liquid.
Example 1 in step sample testing:
0.5073g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the number of milliliters after titration was 25.50ml, thereby giving a calcium carbonate working reference sample content of 100.02%.
Step example 2in sample testing:
0.5285g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the milliliters after titration was 26.57ml, giving a calcium carbonate working reference sample content of 100.04%.
Step (b) example 3 in sample testing:
0.5496g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the number of milliliters after titration was 27.61ml, thereby giving a calcium carbonate working reference sample content of 99.96%.
Example 4 in step sample testing:
0.5345g of a dry constant weight working reference calcium carbonate sample was weighed, wherein the number of milliliters after titration was 26.88ml, giving a working reference calcium carbonate sample content of 100.07%.
Step example 5 in sample testing:
0.5245g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the milliliter number after titration was 26.38ml, thereby obtaining the content of the calcium carbonate working reference sample to be 100.08%.
Step example 6 in sample testing:
0.5182g of a dry constant weight calcium carbonate working reference sample was weighed, wherein the number of milliliters after titration was 26.04ml, thereby giving a calcium carbonate working reference sample content of 99.99%.
Further, the average value calculation was performed for example 1 in the step sample test to example 6 in the step sample test, thereby obtaining an average value of the content of the calcium carbonate working reference samples of example 6 in the step sample test to example 1 in the step sample test of 100.03%.
The measurement results of the calcium carbonate working reference sample in the step of sample detection are as follows:
and (4) when the content of the calcium carbonate sample is obtained by detecting the liquid to be detected, simultaneously carrying out a blank test.
Example 1:
0.5441g and 0.5348g of dry constant-weight calcium carbonate samples are respectively weighed, wherein the milliliter number of the 0.5441g of calcium carbonate sample after titration is 26.99ml, the CaCO3 content of the liquid to be detected is 98.70%, the milliliter number of the 0.5348g of calcium carbonate sample after titration is 26.56ml, and the CaCO3 content of the liquid to be detected is 98.82%.
The calcium carbonate test in this example had an average value of 98.76%.
Example 2:
0.5388g and 0.5224g of dry constant-weight calcium carbonate samples are respectively weighed, wherein the milliliter number of the 0.5388g of calcium carbonate sample after titration is 26.62ml, the CaCO3 content of the liquid to be detected is 98.31%, the milliliter number of the 0.5224g of calcium carbonate sample after titration is 25.80ml, and the CaCO3 content of the liquid to be detected is 98.27%.
The calcium carbonate test in this example had an average value of 98.29%.
Example 3:
0.5172g and 0.5274g of dry constant-weight calcium carbonate samples are respectively weighed, wherein the milliliter number of the 0.5172g of calcium carbonate samples after titration is 25.62ml, the content of CaCO3 in the liquid to be detected is 98.57%, the milliliter number of the 0.5274g of calcium carbonate samples after titration is 26.08ml, and the content of CaCO3 in the liquid to be detected is 98.40%.
The calcium carbonate test in this example had an average value of 98.48%.
Example 4:
0.5362g and 0.5188g of dry constant-weight calcium carbonate samples are respectively weighed, wherein the milliliter number of the 0.5362g of calcium carbonate sample after titration is 26.49ml, the CaCO3 content of the liquid to be detected is 98.30%, the milliliter number of the 0.5188g of calcium carbonate sample after titration is 25.64ml, and the CaCO3 content of the liquid to be detected is 98.34%.
The calcium carbonate test in this example had an average value of 98.32%.
Example 5:
0.5089g and 0.5362g of dry constant-weight calcium carbonate samples are respectively weighed, wherein the milliliter number of the 0.5089g of calcium carbonate sample after titration is 25.25ml, the CaCO3 content of the liquid to be detected is 98.73%, the milliliter number of the 0.5362g of calcium carbonate sample after titration is 26.65ml, and the CaCO3 content of the liquid to be detected is 98.90%.
The calcium carbonate test in this example had an average value of 98.82%.
Example 6:
0.5272g and 0.5465g calcium carbonate samples are respectively weighed, wherein the milliliter number of the 0.5272g calcium carbonate sample after titration is 26.20ml, the content of CaCO3 in the liquid to be detected is 98.89%, the milliliter number of the 0.5465g calcium carbonate sample after titration is 27.17ml, and the milliliter number of the CaCO in the liquid to be detected is 27.17ml3The content of (A) was 98.93%.
The calcium carbonate test in this example had an average value of 98.91%.
The results of the determination of the calcium carbonate content in the test are as follows:
the method for accurately detecting the main content of the industrial calcium carbonate has the following beneficial effects:
(1) the method adopts calcium carbonate reference calibration when calibrating disodium ethylene diamine tetraacetate (EDTA for short), and the dropping point is easy to determine because calcium carbonate is easy to purify and reacts with EDTA in equal quantity.
(2) During calibration and detection, the method changes the phenomenon of advanced dissociation of the end point color by adding the magnesium salt, so that the end point color change is more sensitive, and the detection result is more accurate.
(3) The method can detect fineness without fine fineness, and the mixed powder can be detected by mixing below 35 meshes.
(4) The linear range of the method does not need to be controlled, and the low content and the high content can be detected.
(5) The method has wide sample weighing range and easy weighing, and the sample weighing speed cannot influence the moisture absorption of the sample to be oxidized.
(6) The method solves the problem of high power consumption.
The method for accurately detecting the main content of the industrial calcium carbonate comprises the following steps: preparation: weighing 7.45g of disodium ethylene diamine tetraacetate in a 1000ml beaker, adding a small amount of water, heating for dissolving, and diluting to obtain a solution to be labeled; calibration: placing a dry calcium carbonate working reference sample with constant weight in a 250ml volumetric flask, adding a small amount of water for wetting, then adding 10ml of hydrochloric acid to completely dissolve the calcium carbonate working reference sample, diluting the calcium carbonate working reference sample to a scale with water and shaking up to prepare a calcium carbonate sample solution, calibrating the solution to be calibrated prepared in the preparation step with the calcium carbonate sample solution to prepare a standard solution, and recording data; and simultaneously, in the method, when in calibration and sample detection, the magnesium salt solution is added to change the phenomenon of advanced dissociation of the color of the end point, so that the color change of the end point is more sensitive, and the detection result is more accurate.
Furthermore, the fineness of the calcium carbonate can be detected only by uniformly mixing the calcium carbonate to below 35 meshes without being too fine, the method does not need to control the linear range of the calcium carbonate content and can detect the calcium carbonate content from low content to high content, meanwhile, the method has wider sample weighing range and is easy to weigh, the sample weighing speed does not influence the moisture absorption and oxidation of the sample, and the measurement precision of the sample is improved.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (8)
1. A method for accurately detecting the main content of industrial calcium carbonate is characterized by comprising the following steps:
preparation: weighing 7.45-149 g of disodium ethylene diamine tetraacetate in a 1-20L container, adding a small amount of water, heating for dissolving, and diluting to obtain a solution to be labeled;
calibration: placing a dry calcium carbonate working reference sample with constant weight in a 250ml volumetric flask, adding a small amount of water for wetting, then adding 10ml of hydrochloric acid to completely dissolve the calcium carbonate working reference sample, diluting the calcium carbonate working reference sample to a scale with water and shaking up to prepare a calcium carbonate sample solution, calibrating the solution to be calibrated prepared in the preparation step by using the calcium carbonate sample solution to prepare a standard solution, and recording data;
sample detection: and (2) placing 25mL of the calcium carbonate sample liquid prepared in the calibration step into a 250mL conical flask, sequentially adding 25mL of water, 2mL of 100g/L magnesium salt solution, 10mL of 100g/L sodium hydroxide solution and a little calcium indicator to prepare a liquid to be detected, then dripping the standard solution in the calibration step into the liquid to be detected until the liquid to be detected is changed into pure blue as an end point and does not fade for 30s, at the moment, calculating the content of calcium carbonate according to corresponding notations, and simultaneously performing a blank test.
2. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein in the calibration step, the mass of the calcium carbonate working reference sample is 0.45-0.60 g.
3. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein in the calibration step, the temperature of the dry calcium carbonate working reference sample is controlled to be 105 ℃ to 115 ℃, and the calcium carbonate working reference sample is accurate to 0.0002 g.
4. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein the volume ratio of hydrochloric acid in the calibration step is 1: 1.
5. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein in the calibration step, the calcium carbonate sample solution after shaking is filtered if the calcium carbonate sample solution is turbid, and the calcium carbonate sample solution after shaking is not turbid, so that the calcium carbonate sample solution is not required to be filtered.
6. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein in the sample detection step, 25ml of water added in a 250ml conical flask is 25ml of distilled water.
7. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein in the step of preparing, the volume of the prepared solution to be calibrated is 1000 ml.
8. The method for accurately detecting the main content of industrial calcium carbonate according to claim 1, wherein in the sample detection step, the standard solution calibrated in the step is dripped into the solution to be detected until the end point of the solution to be detected turns to pure blue and does not fade for 30 s.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102507546A (en) * | 2011-09-28 | 2012-06-20 | 吉林恒联精密铸造科技有限公司 | Method for detecting content of calcium oxide in limestone |
| CN104280369A (en) * | 2013-10-31 | 2015-01-14 | 东旭集团有限公司 | Method for efficiently and accurately detecting main content of industrial calcium carbonate |
| CN105067613A (en) * | 2015-07-21 | 2015-11-18 | 姚祖英 | Method for detecting contents of calcium and magnesium in natural limestone |
-
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102507546A (en) * | 2011-09-28 | 2012-06-20 | 吉林恒联精密铸造科技有限公司 | Method for detecting content of calcium oxide in limestone |
| CN104280369A (en) * | 2013-10-31 | 2015-01-14 | 东旭集团有限公司 | Method for efficiently and accurately detecting main content of industrial calcium carbonate |
| CN105067613A (en) * | 2015-07-21 | 2015-11-18 | 姚祖英 | Method for detecting contents of calcium and magnesium in natural limestone |
Non-Patent Citations (5)
| Title |
|---|
| 化工商品检验手册编委会, 中国科学技术大学出版社 * |
| 化工商品检验手册编委会: "《化学分析技术》", 中国科学技术大学出版社, pages: 129 - 131 * |
| 化工商品检验手册编委会: "食品添加剂用碳酸钙", 《化工商品检验手册》 * |
| 化工商品检验手册编委会: "食品添加剂用碳酸钙", 《化工商品检验手册》, 31 January 1996 (1996-01-31), pages 410 - 411 * |
| 曹宏燕: "碳酸钙含量的测定（一）", 《冶金材料分析技术与应用》, 30 September 2008 (2008-09-30), pages 778 - 780 * |
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