Calcium phase analysis method for baishan ore fluorite concentrate

Abstract

The application discloses a method for analyzing calcium phase of Baiyunebo fluorite concentrate, and the existence form and state of the calcium phase in the Baiyunebo fluorite concentrate are studied by a chemical phase analysis method, and a leaching solvent, a leaching temperature and a leaching time are selected accordingly, so that the separation purpose is achieved. The method combines a systematic method with single analysis, and fills the blank of the method for analyzing the calcium phase of the Baiyunebo fluorite concentrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical detection, in particular to a method for analyzing calcium phase of fluorite concentrate in Baiyunebo. BACKGROUND

[0002] China is rich in fluorite resources, and fluorite ore is an important non-metallic mineral in China, which is often used to prepare hydrofluoric acid, fluoride and other substances.

[0003] The ore deposit in Baiyunebo mining area is a large-scale deposit of niobium, rare earth and iron, which is characterized by the intergrowth relationship and complexity of various minerals. The iron minerals in the ore are very closely associated with fluorite, heavy spar and nepheline. Fluorite, heavy spar and nepheline are produced in aggregates. At the same time, bastnaesite often coexists with nepheline and fluorite, and fluorite contains fine-grained inclusions of bastnaesite. Monazite coexists with heavy spar, fluorite, nepheline and quartz. Therefore, when a certain mineral is enriched, other minerals will also appear as associated components. The composition of fluorite concentrate in Baiyunebo is relatively complex, and there are many interference items in the analysis of calcium composition. The main forms of calcium are dolomite, fluorite, apatite, fluorcarbonate, and wollastonite. When the calcium content is determined by EDTA titration method in GB / T5195.1-2017 method, other calcium compounds will be brought in when calculating the content of calcium fluoride. Distillation method is used to determine the content of fluorine in calcium fluoride, and fluorcarbonate is also interfered. Therefore, the existing standards cannot meet the chemical phase analysis of calcium in fluorite concentrate in Baiyunebo with intergrowth relationship and complexity, and there is no chemical phase analysis method for calcium in fluorite concentrate in Baiyunebo at home and abroad. Therefore, it is urgent to carry out research to establish relevant phase analysis method and provide useful information on phase composition of raw materials and intermediate products for beneficiation process design and production process in time. SUMMARY

[0004] The purpose of the present application is to provide a method for analyzing calcium phase of fluorite concentrate in Baiyunebo, which studies the form and state of calcium phase in fluorite concentrate in Baiyunebo by chemical phase analysis method, and selects leaching solvent, leaching temperature and leaching time accordingly to achieve the purpose of separation.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a method for analyzing calcium phase of fluorite concentrate in Baiyunebo, which comprises the following steps:

[0007] 1) Determination of calcium carbonate phase content

[0008] Take m1 g of sample into a beaker, add acetic acid solution, cover with a watch glass, and let stand at room temperature for a certain period of time, stirring once in the middle; filter with slow speed filter paper, transfer the residue to the filter paper, wash the beaker with water for several times, wash the residue with water for several times, and dilute the filtrate to a volume of V1 in a volumetric flask with pure water; take V2 volume of the sample solution into a conical flask, add pure water, magnesium sulfate solution, triethanolamine, potassium hydroxide solution, mixed indicator, and titrate with EDTA standard titration solution until the green fluorescence of the sample solution disappears, which is the end point, and the volume of the consumed EDTA standard solution is V3; perform a blank test with the sample, and the volume of the consumed EDTA standard solution for the titration of the blank test solution is V 03 ;

[0009] The content of calcium carbonate is calculated according to formula (1):

[0010] ……………………………………(1)

[0011] In the formula:

[0012] T EDTA : the titration degree of EDTA standard titration solution for calcium carbonate, with the unit of g / mL;

[0013] V1: the volume of the sample solution, with the unit of mL;

[0014] V2: the volume of the sample solution taken, with the unit of mL;

[0015] V3: the volume of the consumed EDTA standard solution for the titration of the sample solution, with the unit of mL;

[0016] V 03 : the volume of the consumed EDTA standard solution for the titration of the blank test solution, with the unit of mL;

[0017] m1: the mass of the sample, with the unit of g;

[0018] 2) Determination of the phase content of calcium fluoride

[0019] Put the residue and filter paper in step 1) into a beaker, drop a few drops of anhydrous ethanol, add hydrochloric acid-boric acid-sulfuric acid mixed acid, cover with a watch glass, shake without making the sample clump, heat to boiling at low temperature, remove and cool, rinse the watch glass and beaker with water, heat the water to dilute; heat to micro-boiling again, filter to a volumetric flask with a volume of V4 using fast filter paper; wash the beaker and filter paper with hot hydrochloric acid several times, wash the residue with pure water several times, cool to room temperature, dilute to the scale with water, mix well; take V5 volume of the test solution into a conical flask, add pure water, magnesium sulfate solution, triethanolamine, potassium hydroxide solution, mixed indicator; titrate with EDTA standard titration solution until the green fluorescence of the test solution disappears as the end point; the volume of the consumed EDTA standard solution is V6; take a blank test with the sample, the volume of the consumed EDTA of the titrated blank test solution is V 06 ;

[0020] The content of calcium fluoride is calculated according to formula (2):

[0021] …………………………………(2)

[0022] In the formula:

[0023] T EDTA : the titration degree of EDTA standard titration solution to calcium fluoride, unit g / mL;

[0024] V4: the volume of the sample solution, unit mL;

[0025] V5: the volume of the sample solution, unit mL;

[0026] V6: the volume of the consumed EDTA standard solution of the titrated sample solution, unit mL;

[0027] V 06 : the volume of the consumed EDTA standard solution of the titrated blank test solution, unit mL;

[0028] m1: the mass of the sample, unit g;

[0029] 3) Determination of the phase content of fluorocarbon cerium calcium

[0030] Take m2 sample into a conical flask, dissolve on a high-temperature electric furnace, constantly shake the conical flask during the period, fine small bubbles disappear, the reaction tends to be calm, add perchloric acid, heat to the white smoke of perchloric acid disappears, remove and cool slightly;

[0031] Slowly add sulfuric acid solution, shake well, cool to room temperature with running water;

[0032] Add urea solution, drop with sodium nitrite solution until the pink color of trivalent manganese disappears, and slightly excess;

[0033] Add benzene o-amino benzoic acid solution, titrate with ferrous ammonium sulfate standard solution until the end point of purple red to bright yellow, record the titration milliliter number V7;

[0034] The mass fraction of total cerium in fluorite concentrate is calculated according to formula (3):

[0035] ………………………………………(3)

[0036] In the formula,

[0037] ω (Ce): mass fraction of total cerium, unit (%);

[0038] C: concentration of ferrous ammonium sulfate standard solution, unit is mol / L (mol / L);

[0039] V7: volume of ferrous ammonium sulfate standard solution consumed in titration of sample, unit is milliliter (mL);

[0040] m2: sample mass, unit is gram (g);

[0041] 140.12 is the molar mass of cerium, unit is g / mol (g / mol);

[0042] Another sample m3 is weighed in a magnetic boat, the magnetic boat is placed in a muffle furnace and burned for a certain time; the burned product is poured into a beaker, dilute sulfuric acid solution is added, and the beaker is placed in an electric furnace for heating or immersed in a water bath for leaching. The filter paper and residue are quickly filtered, and the filter paper and residue are placed in the original beaker. The filtrate is reserved for use in calcium phosphate; phosphoric acid, perchloric acid and nitric acid are added to the beaker, which is placed on an electric furnace for heating. After the liquid surface is calm, it is taken out; sulfuric acid solution is added, and ferrous ammonium sulfate standard titration solution is used for titration. The titration milliliter number V8 is recorded, and formula (4) is used for calculation to obtain the result of cerium phosphate content;

[0043] ………………………………(4)

[0044] In the formula,

[0045] ω (P-Ce): mass fraction of cerium in cerium phosphate, unit (%);

[0046] C: concentration of ferrous ammonium sulfate standard solution, unit is mol / L (mol / L);

[0047] V8: volume of ferrous ammonium sulfate standard solution consumed in titration of sample, unit is milliliter (mL);

[0048] m3: sample mass, unit is gram (g);

[0049] 140.12 is the molar mass of cerium, unit is gram per mole (g / mol);

[0050] Subtract the cerium content in cerium phosphate from the total cerium content, that is, the cerium content in fluorocarbon cerium calcium, so as to convert the calcium content in fluorocarbon cerium calcium;

[0051] The mass fraction (%) of cerium (F-Ce) in fluorocarbon cerium calcium is calculated according to formula (5):

[0052] ………………………………(5)

[0053] In the formula:

[0054] ω (F-Ce): mass fraction of cerium in fluorocarbon cerium calcium;

[0055] ω (Ce): total cerium mass fraction;

[0056] ω (P-Ce): mass fraction of cerium in cerium phosphate;

[0057] 4) Determination of calcium phosphate phase content

[0058] The filtrate in step 3 is transferred to a beaker, saturated boric acid solution, hydrogen peroxide, boiling water bath leaching, slow filter paper is used to filter the filtrate to a 200 mL volumetric flask; Wash the beaker and insoluble with pure water for several times, cool to room temperature, dilute to the mark with water and mix well; Take 10 mL of test solution in a 50 mL volumetric flask, add ascorbic acid, bismuth nitrate solution, ammonium molybdate solution, add hot pure water to constant volume, stand for a certain time, and then determine the total P content with spectrophotometer. The content of Ca3(PO4)2 is calculated;

[0059] 5) Determination of calcium silicate phase content

[0060] Take m4 sample, put the test material in a platinum crucible pre-filled with mixed flux, mix well, and then cover with mixed flux; gradually increase the furnace temperature, melt, take out, rotate the platinum crucible, and cool; rinse the outer wall of the platinum crucible with water, place the platinum crucible in a beaker, add hydrochloric acid, and heat at low temperature to leach the melt. Rinse the platinum crucible with water; heat at low temperature until the test solution is clear, and cool to room temperature; transfer the test solution to a volumetric flask, dilute to the mark with water, mix well; take the stock solution and place it in a conical flask, add water, add triethanolamine, mix well, add potassium hydroxide solution and calcium indicator, mix well; titrate with EDTA standard titration solution until the test solution changes from red to bright blue as the end point; the volume of EDTA standard solution consumed is V9; do a blank test with the sample, and the volume of EDTA consumed by the titrated blank test solution is V 09 ;

[0061] The mass fraction of total calcium is calculated according to formula (6):

[0062] …(6)

[0063] In the formula:

[0064] ω(Ca): mass fraction of total calcium;

[0065] T EDTA : titration degree of EDTA standard titration solution to calcium, unit g / mL;

[0066] V9: volume of EDTA standard titration solution consumed in titration of total calcium, unit mL;

[0067] V 09 : volume of EDTA standard titration solution consumed in titration of blank test solution, unit mL;

[0068] m4: sample amount corresponding to the test solution, unit g;

[0069] Subtract calcium carbonate, calcium fluoride, fluorocarbon cerium calcium, calcium phosphate from total calcium, and the calcium silicate is obtained.

[0070] Further, m1 and m4 are 0.5000 g, and m2 and m3 are 0.2000 g.

[0071] Further, V1 and V4 are equal to 250 ml, and V2 and V5 are equal to 25 ml.

[0072] Further, the mixed ratio of the mixed indicator is that 0.20 g of calcein, 0.15 g of thymol phenolphthalein and 20 g of anhydrous potassium sulfate are weighed in a mortar and ground to obtain the mixed indicator.

[0073] Further, the hydrochloric acid-boric acid-sulfuric acid mixed acid is obtained by the following method: 12.5 g of boric acid is added to a 250 mL beaker, about 100 mL of water is added, 25 mL of sulfuric acid (ρ=1.84 g / mL) is slowly added, and the boric acid is dissolved by heating. After cooling, it is transferred to a reagent bottle containing 250 mL of hydrochloric acid (ρ=1.19 g / mL) and 600 mL of water, and cooled to room temperature, and diluted with water to 1 L.

[0074] Further, the saturated boric acid solution is obtained by the following method: 200 mL of concentrated hydrochloric acid is slowly added to 800 mL of water, 60 g of boric acid is added, and stirred until the boric acid no longer dissolves, and then left to stand for 30 min. The upper clear liquid is the saturated boric acid solution.

[0075] Further, the electric furnace heating is all low-temperature electric furnace.

[0076] Compared with the prior art, the beneficial technical effects of the present application are:

[0077] 1. The combination of system method and single analysis fills the blank of fluorite concentrate calcium phase analysis method in Baiyunebo, and lays a solid foundation for writing national standard method in the future.

[0078] 2. Since there is no suitable solvent to separate calcium fluoride, fluorocarbon calcium cerium and calcium phosphate in fluorite, the determination and analysis of fluorocarbon calcium cerium is taken as a starting point from the cerium element of the compound, the total cerium is determined by cerium determination method, then the content of cerium phosphate is determined by cerium determination method through oxidation roasting, acid leaching, and filtering residue, and the content of fluorocarbon calcium cerium is obtained by using difference method; the filtrate produced in the process of determining fluorocarbon calcium cerium is used to determine the content of calcium phosphate by bismuth phosphorus molybdenum blue breadth method.

[0079] 3. Reliable technical support is provided for mineral processing and metallurgy. BRIEF DESCRIPTION OF DRAWINGS

[0080] The application will be further described below in combination with the description of the accompanying drawings.

[0081] Figure 1 The flow chart of fluorite concentrate calcium phase analysis method in Baiyunebo is provided. DETAILED DESCRIPTION

[0082] A fluorite concentrate calcium phase analysis method in Baiyunebo, comprising the following steps:

[0083] 1. Determination of calcium carbonate phase content

[0084] 0.5000 g of sample is weighed in a 250 mL beaker, 10 mL of 10% acetic acid solution is added, a watch glass is covered, and it is placed at room temperature for 30 min, and it is shaken or stirred once every 5 min.

[0085] It is filtered with slow speed filter paper. The insoluble matter is completely transferred to the filter paper, and the beaker is washed with water for 3-5 times, and the residue is washed with water for 3-5 times.

[0086] The filtrate is diluted to 250 mL in a volumetric flask with pure water.

[0087] 25.00 mL of test solution is taken in a 250 mL conical flask, 25 mL of water, 2 drops of 5 g / L magnesium sulfate solution, 30% triethanolamine 5 mL, 200 g / L potassium hydroxide solution 20 mL, and 0.1 g mixed indicator are added, and the test solution is titrated with EDTA standard titration solution until the green fluorescence disappears as the end point, and a blank test is performed with the test sample.

[0088] The content of calcium carbonate is calculated according to formula (1).

[0089] ……………………………………(1)

[0090] In the formula:

[0091] EDTA: EDTA standard titration solution titration degree for calcium carbonate, unit g / mL;

[0092] V1: the volume of the sample solution, unit mL;

[0093] V2: the volume of the sample solution, unit mL;

[0094] V3: the volume of the sample solution, unit mL;

[0095] V03: the volume of the sample solution, unit mL;

[0096] m1: the mass of the sample, unit g.

[0097] 2. Determination of calcium fluoride phase content

[0098] The filter residue and filter paper in step 1 were placed in a 250 mL beaker, a few drops of anhydrous ethanol were added, 50 mL of hydrochloric acid-boric acid-sulfuric acid mixed acid was added, a watch glass was covered, and the sample was shaken without clumping. It was heated to boiling at low temperature for 20 min.

[0099] After cooling, the watch glass and beaker were rinsed with water, and the water was heated to dilute to 100 mL. It was heated to a slight boil again, filtered on a 250 mL volumetric flask with rapid filter paper. The beaker and filter paper were washed with 1% hot hydrochloric acid 5-6 times, and the insoluble matter was washed with pure water 7-8 times. It was cooled to room temperature, diluted to the mark with water, and mixed well.

[0100] 25.00 mL of the sample solution was taken into a 250 mL conical flask, 25 mL of pure water, 2 drops of 5 g / L magnesium sulfate solution, 5 mL of 30% triethanolamine, 20 mL of 200 g / L potassium hydroxide solution, and 0.1 g-0.2 g of mixed indicator were added. Titrate with EDTA standard titration solution until the green fluorescence of the sample solution disappears (observe on a black background pad) as the end point, and do a blank test with the sample.

[0101] The content of calcium fluoride was calculated according to formula (2).

[0102] …………………………………(2)

[0103] In the formula:

[0104] TEDTA: EDTA standard titration solution titration degree for calcium fluoride, unit g / mL;

[0105] V4: the volume of the sample solution, unit mL;

[0106] V5: volume of the aliquot sample solution, in mL;

[0107] V6: volume of EDTA standard solution consumed for titrating the aliquot sample solution, in mL;

[0108] V06: volume of EDTA standard solution consumed for titrating the aliquot blank solution, in mL;

[0109] m1: mass of the sample, in g.

[0110] 3. Determination of fluorocarbon cerium calcium phase content

[0111] Weigh 0.2000 g of sample into a 300 ml conical flask, add 15 ml of phosphoric acid, and dissolve on a high-temperature electric furnace. Shake the conical flask constantly during the process, and when fine small bubbles disappear and the reaction tends to be calm, add 2 ml of perchloric acid, heat until the white smoke of perchloric acid disappears, and then remove it slightly cool.

[0112] Slowly add 80 ml of 5% sulfuric acid solution, shake well, and cool to room temperature with running water.

[0113] Add 5 ml of 200 g / L urea solution, and drop 2 g / L sodium nitrite solution to the pink color of trivalent manganese until it disappears, with an excess of 0.5 ml.

[0114] Add 2 drops of 2 g / L phenyl o-amino benzoic acid solution, and titrate with ferrous ammonium sulfate standard solution until the purple red color just changes to bright yellow as the end point, and record the titration milliliter number.

[0115] Calculate the mass fraction (%) of total cerium in fluorite concentrate according to formula (3):

[0116] ………………………………………(3)

[0117] In the formula:

[0118] ω(Ce): mass fraction of total cerium, in (%);

[0119] C: concentration of ferrous ammonium sulfate standard solution, in moles per liter (mol / L);

[0120] V7: volume of ferrous ammonium sulfate standard solution consumed for titrating the sample, in milliliters (mL);

[0121] m2: sample mass, in grams (g);

[0122] 140.12 is the molar mass of cerium, in grams per mole (g / mol).

[0123] Another 0.2000 g of the sample was weighed into a magnetic boat, which was placed in a muffle furnace and burned at 700°C for 30 min.

[0124] The burned product was poured into a 300 mL beaker, 5% dilute sulfuric acid solution was added, and the beaker was placed on an electric furnace (or immersed in a water bath) for heating (or leaching). The filtrate was quickly filtered with filter paper.

[0125] The filter paper and residue were placed in the original beaker, 15 ml of phosphoric acid (p = 1.70 g / mL), 5 ml of perchloric acid (70-72%), and 10 ml of nitric acid (p = 1.42 g / mL) were added to the beaker, and the beaker was placed on an electric furnace for heating. After the liquid surface was calm, it was removed.

[0126] 90 ml of 5% sulfuric acid solution was added, and the standard titration solution of ferrous ammonium sulfate was titrated. The titration milliliter number V8 was recorded, and the result was calculated by formula (4) to obtain the cerium content in cerium phosphate.

[0127] The mass fraction (%) of cerium in cerium phosphate in fluorocarbon cerium calcium was calculated according to formula (4):

[0128] ………………………………(4)

[0129] In the formula:

[0130] ω(P-Ce): mass fraction of cerium in cerium phosphate, unit (%);

[0131] C: concentration of ferrous ammonium sulfate standard solution, unit mol / L;

[0132] V8: volume of ferrous ammonium sulfate standard solution consumed in titration of the sample, unit mL;

[0133] m3: sample mass, unit g;

[0134] 140.12 is the molar mass of cerium, unit g / mol.

[0135] The content of cerium in fluorocarbon cerium calcium is obtained by subtracting the content of cerium in cerium phosphate from the total cerium content. Thus, the calcium content in fluorocarbon cerium calcium is converted.

[0136] The mass fraction (%) of cerium (F-Ce) in fluorocarbon cerium calcium was calculated according to formula (5):

[0137] ………………………………(5)

[0138] In the formula:

[0139] ω(F-Ce): mass fraction of cerium in fluorocarbon cerium calcium;

[0140] ω(Ce): Total cerium mass fraction;

[0141] ω(P-Ce): The mass fraction of cerium in cerium phosphate.

[0142] 4. Determination of calcium phosphate phase content

[0143] Transfer the filtrate from step 3 to a beaker, add saturated boric acid solution and 1 mL of 30% hydrogen peroxide, immerse in a boiling water bath for 40 min, and filter the filtrate through slow-speed filter paper into a 200 mL volumetric flask. Wash the beaker and insoluble matter 7 to 8 times with pure water, cool to room temperature, and dilute with water to the mark and mix well.

[0144] Take 10.00 mL of the test solution into a 50 mL volumetric flask, add 2 mL of 10 g / L ascorbic acid, 5 mL of 10 g / L bismuth nitrate solution, and 5 mL of 40 g / L ammonium molybdate solution. Add hot pure water to make up the volume. After standing for 20 min, determine the total P content using a spectrophotometer and calculate the Ca3(PO4)2 content.

[0145] 5. Determination of calcium silicate phase content

[0146] Weigh 0.5000g of the sample and place it in a platinum crucible pre-filled with 3.0g of mixed flux (sodium carbonate: boric acid = 2:1). Mix well and then cover with 1.0g of mixed flux. Gradually raise the furnace temperature to 950℃~1000℃ and melt for 10 minutes. Remove the crucible, rotate it, and allow it to cool. Rinse the outer wall of the platinum crucible with water. Place the crucible and lid in a 300mL beaker, add 75mL of hydrochloric acid (1:5), and heat at a low temperature to leach out the molten material. Wash the crucible with water. Heat at a low temperature until the solution is clear and cool to room temperature. Transfer the solution to a 250mL volumetric flask, dilute to the mark with water, and mix well.

[0147] Aliquot 25.00 mL and place it in a 500 mL Erlenmeyer flask. Add 25 mL of water and 5 mL of triethanolamine (1:4), mix well, add 20 mL of 200 g / L potassium hydroxide solution, and approximately 0.1 g of calcium indicator (1 g of calcium indicator is ground and mixed with 100 g of sodium chloride). Mix well. Titrate with EDTA standard titration solution until the test solution changes from red to bright blue. Perform a blank test along with the sample. The volume of EDTA consumed in the titration of the blank test solution is V. 09 .

[0148] Calculate the total calcium mass fraction according to formula (6):

[0149] …………………………………………(6)

[0150] In the formula:

[0151] ω(Ca): mass fraction of total calcium;

[0152] T EDTA : titration degree of EDTA standard titration solution to calcium, unit: g / mL;

[0153] V9: volume of EDTA standard titration solution consumed in titration of total calcium, unit: mL;

[0154] V 09 : volume of EDTA standard titration solution consumed in titration of blank test solution, unit: mL;

[0155] m4: sample amount corresponding to the test solution, unit: g.

[0156] Subtracting calcium carbonate, calcium fluoride, fluorocarbon calcium cerium, calcium phosphate from total calcium is calcium silicate.

[0157] Precision refers to the degree of coincidence of multiple repeated measurement results under the same conditions, and the size of precision is represented by deviation, and the smaller the deviation is, the higher the precision is. The white cloud obo fluorite concentrate sample BS9-19 and BS11-4 are determined in parallel for three times by the above method, and then the relative standard deviation RSD(%) of the determination results is calculated.

[0158] Table 1: Results of precision experiment of sample BS9-19 of the embodiment of the present application

[0159]

[0160] Table 2: Results of precision experiment of sample BS11-4 of the embodiment of the present application

[0161]

[0162] According to the detection results in Tables 1 and 2, the RSD is within 5%, and the experiment shows that the precision of the detection method provided by the present application is good.

[0163] The standard addition recovery rate can determine the accuracy of the analysis results. Two samples are taken, one of which is added with a quantitative standard substance of the measured component, and both are analyzed according to the same analysis steps, the difference between the results of the sample with standard addition and the sample without standard addition is the standard addition recovery rate of the sample, that is, standard addition recovery rate = (determination value of sample with standard addition - determination value of sample) ÷ standard addition amount × 100%. The white cloud obo fluorite concentrate sample BS9-33 is determined for phase composition of calcium by the above experimental method, and the standard addition recovery rate experiment is carried out by quantitatively adding calcium carbonate (CaCO3), calcium fluoride (CaF2), fluorocarbon calcium cerium (CaCeF(CO3)2), calcium phosphate (Ca3(PO3)2), and calcium silicate (CaSiO3). The experimental results are shown in Table 3.

[0164] Table 3 results of recovery experiment of the embodiment of the present application

[0165]

[0166] Table 3 lists three sets of parallel spiked recovery experiment data, three sets of experiments are respectively spiked recovery experiments on 5 kinds of phases. According to the recovery results in Table 3, it shows that the accuracy of the detection method provided by the present application is better.

[0167] In summary, the above method of the present application can be combined with system analysis and single analysis to detect the content of calcium carbonate, calcium fluoride, fluorocarbon calcium cerium, calcium phosphate and calcium silicate, a total of 5 kinds of calcium phases. The precision and accuracy of the method are good, which can meet the determination requirements, and has low cost, high efficiency and certain popularization value.

[0168] The above-described embodiments are only preferred modes of the present application and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for analyzing the calcium phase of a Baiyunebo fluorite concentrate, characterized by comprising the following steps: Comprising the following steps: ​ 1) Determination of calcium carbonate phase content Take m1 of the sample into a beaker, add acetic acid solution, cover with a watch glass, and let stand at room temperature for a certain period of time, stirring once in the middle. Filter with slow speed filter paper, transfer all the residue to the filter paper, wash the beaker with water several times, wash the residue with water several times, and dilute the filtrate to a volume of V1 in a volumetric flask with pure water. Take V2 of the test solution into a conical flask, add pure water, magnesium sulfate solution, triethanolamine, potassium hydroxide solution, and mixed indicator, titrate with EDTA standard titration solution until the green fluorescence of the test solution disappears, which is the end point. The volume of EDTA standard solution consumed is V3. Perform a blank test with the sample, and the volume of EDTA consumed in titrating the blank test solution is V 03 ; The content of calcium carbonate is calculated according to formula (1): ……………………………………（1）； In the formula: T EDTA : EDTA standard titration solution titration degree of calcium carbonate, unit g / mL; V1: volume of sample solution, unit: mL; V2: volume of sample solution, unit: mL; V3: volume of EDTA standard solution consumed by titration of sample solution, unit: mL; V 03 : Volume of EDTA standard solution consumed by titration of the aliquot blank test solution, in mL; m1: sample mass, unit: g; 2) Determination of calcium fluoride phase content The residue and filter paper in step 1) are placed in a beaker, a few drops of anhydrous ethanol are added, hydrochloric acid-boric acid-sulfuric acid mixed acid is added, a watch glass is covered, and the sample is shaken without clumping, heated to boiling at low temperature, removed and cooled, the watch glass and beaker are rinsed with water, and the water is heated and diluted; heated to a slight boil again, filtered with fast filter paper into a volumetric flask with a volume of V4, washed the beaker and filter paper with hot hydrochloric acid several times, washed the residue with pure water several times, cooled to room temperature, diluted to the scale with water, and mixed; V5 volume of the test solution is taken in a conical flask, pure water, magnesium sulfate solution, triethanolamine, potassium hydroxide solution, and mixed indicator are added; titrated with EDTA standard titration solution until the green fluorescence of the test solution disappears as the end point; the volume of EDTA standard solution consumed is V6; a blank test is performed with the sample, and the volume of EDTA consumed by titration of the blank test solution is V 06 ; The content of calcium fluoride is calculated according to formula (2): …………………………………（2）； In the formula: T EDTA : EDTA standard titration solution titration degree of calcium fluoride, unit g / mL; V4: volume of sample solution, unit: mL; V5: volume of sample solution, unit: mL; V6: volume of EDTA standard solution consumed by titration of sample solution, unit: mL; V 06 : Volume of EDTA standard solution consumed by titration of the aliquot blank test solution, in mL; m1: sample mass, unit: g; 3) Determination of fluorocarbon cerium calcium phase content Take m2 sample in a conical flask, add phosphoric acid, dissolve on a high-temperature electric furnace, constantly shake the conical flask during the process, fine small bubbles disappear, the reaction tends to be calm, add perchloric acid, heat until the white smoke of perchloric acid disappears, and then take it out when it is slightly cool; Slowly add sulfuric acid solution, shake well, and cool to room temperature with running water; Add urea solution, drop sodium nitrite solution until the pink color of trivalent manganese disappears with a slight excess; Add benzene o-amino benzoic acid solution, titrate with ferrous ammonium sulfate standard solution until the purple red color just changes to bright yellow as the end point, and record the titration milliliter number V7; The mass fraction of total cerium in fluorite concentrate is calculated according to formula (3): ………………………………………(3)； In the formula: ω(Ce): mass fraction of total cerium, unit: %; C: concentration of ferrous ammonium sulfate standard solution, unit: mol / L; V7: volume of ferrous ammonium sulfate standard solution consumed by titration of sample, unit: mL; m2: sample mass, unit: g; 140.12 is the molar mass of cerium, unit: g / mol; Another m3 sample is weighed in a magnetic boat, the magnetic boat is placed in a muffle furnace, and is burned for a certain time; the burned product is poured into a beaker, dilute sulfuric acid solution is added, and is placed in an electric furnace for heating or immersed in a water bath for leaching; a filter paper is quickly quantitatively filtered, the filter paper and filter residue are put into the original beaker, and the filtrate is left for use for calcium phosphate; phosphoric acid, perchloric acid and nitric acid are added in the beaker, and are placed on an electric furnace for heating; after the liquid surface is calm, it is taken out; sulfuric acid solution is added, and is titrated with ferrous ammonium sulfate standard titration solution; the titration milliliter number V8 is recorded, and formula (4) is used for calculation to obtain the result as the content of cerium phosphate; ………………………………(4)； In the formula: ω(P-Ce): mass fraction of cerium in cerium phosphate, unit: %; C: concentration of ferrous ammonium sulfate standard solution, unit: mol / L; V8: volume of ferrous ammonium sulfate standard solution consumed by titration of sample, unit: mL; m3: sample mass, unit: g; 140.12 is the molar mass of cerium, unit: g / mol; The content of cerium in fluorocarbon cerium calcium is obtained by subtracting the content of cerium in cerium phosphate from the total content of cerium, so as to convert the content of calcium in fluorocarbon cerium calcium; The mass fraction of cerium (F-Ce) in fluorocarbon cerium calcium is calculated according to formula (5): ………………………………(5)； In the formula: ω(F-Ce): mass fraction of cerium in fluorocarbon cerium calcium; ω(Ce): mass fraction of total cerium; ω(P-Ce): mass fraction of cerium in cerium phosphate; 4) Determination of calcium phosphate phase content The filtrate in step 3 is transferred to a beaker, saturated boric acid solution, hydrogen peroxide, boiling water bath, and the filtrate is filtered with slow filter paper into a 200 mL volumetric flask; the beaker and insoluble are washed with pure water for several times, cooled to room temperature, diluted with water to the mark, and mixed well; 10 mL of the test solution is taken into a 50 mL volumetric flask, ascorbic acid, bismuth nitrate solution, ammonium molybdate solution, hot pure water is added to constant volume, and after standing for a certain period of time, the total P content is determined by spectrophotometry, and the Ca3(PO4)2 content is calculated; 5) Determination of calcium silicate phase content Take the sample, put the sample in the platinum crucible which has mixed flux in advance, mix, cover with mixed flux again; gradually increase the furnace temperature, melt, take out, rotate the platinum crucible, cool; rinse the outer wall of the platinum crucible with water, put the platinum crucible in a beaker, add hydrochloric acid, heat at low temperature to leach the melt, wash the platinum crucible with water; heat at low temperature until the test solution is clear, cool to room temperature; move the test solution into a volumetric flask, dilute to the scale with water, mix; take the test solution, put it into a conical flask, add water, add triethanolamine, mix, add potassium hydroxide solution and calcium indicator, mix; titrate with EDTA standard titration solution until the test solution changes from red to bright blue as the end point; the volume of the consumed EDTA standard solution is V9; do a blank test with the sample, the volume of the consumed EDTA for titrating the divided blank test solution is V 09 ; The mass fraction of total calcium is calculated according to formula (6): …………………………………………(6)； In the formula: ω(Ca): mass fraction of total calcium; T EDTA : EDTA standard titration solution titration degree for calcium, unit g / mL; V9: volume of EDTA standard titration solution consumed in titration of total calcium, unit: mL; V 09 : Volume of EDTA standard titration solution consumed by titration blank test solution, in mL; m4: amount of test material corresponding to the test solution, unit: g; The total calcium minus calcium carbonate, calcium fluoride, fluorocarbon cerium calcium, and calcium phosphate is the calcium silicate.

2. The method according to claim 1, characterized in that: m1 is 0.5000 g, and m2 and m3 are 0.2000 g.

3. The method according to claim 1, characterized in that: V1 and V4 are equal to 250 ml, and V2 and V5 are equal to 25 ml.

4. The method according to claim 1, characterized in that: The mixed ratio of the mixed indicator is 0.20 g of calcein, 0.15 g of thymolphthalein, and 20 g of anhydrous potassium sulfate, which are finely ground in a mortar and mixed evenly.

5. The method according to claim 1, characterized in that: Hydrochloric acid-boric acid-sulfuric acid mixed acid is obtained by the following method: take 12.5 g of boric acid in a 250 mL beaker, add 100 mL of water, slowly add 25 mL of sulfuric acid, ρ=1.84 g / mL, heat to dissolve boric acid; cool slightly, transfer to a reagent bottle containing 250 mL of hydrochloric acid, ρ=1.19 g / mL, and 600 mL of water, cool to room temperature, and dilute with water to 1 L.

6. The method according to claim 1, characterized in that: Saturated boric acid solution is obtained by the following method: 200 mL of concentrated hydrochloric acid is slowly added to 800 mL of water, 60 g of boric acid is added, stirred until the boric acid no longer dissolves, and left to stand for 30 min. The upper clear liquid is the saturated boric acid solution.

7. The method according to claim 1, characterized in that: Low-temperature electric furnaces are used for heating.

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