JC/T 1088-2008Methods for chemical analysis of granulated electric furnace phosphorous slag (English PDF)

4.1 Number of tests and requirements

The number of tests per determination is specified as two. Use the average

value of the two tests to express the determination result.

Before the analysis, the specimen shall be baked at 105 °C ~ 110 °C for 2 h,

cooled to room temperature in a desiccator, then weighed.

In the chemical analysis, unless otherwise stated, it must determine the loss on

ignition at the same time. For other determinations, it shall carry out the blank

test at the same time, meanwhile correct the test results.

4.2 Expression of mass, volume, results

Use "grams (g)" to express mass, accurate to 0.0001 g. The burette's volume

is expressed in "milliliter (mL)", accurate to 0.05 mL. The unit of titer is

expressed in "milligram per milliliter (mg/mL)".

The titer of chloride ions in the standard titration solution of mercury nitrate

retains three significant digits after the rounding off. The titer and volume ratio

of other standard titration solutions retain four significant digits after the

rounding off.

Unless otherwise stated, the results of each analysis are based on mass

fraction. The analytical results of the chloride ion are expressed in % to three

decimal places. The analytical results of other items are expressed in % to two

decimal places.

4.3 Blank test

Use the same amount of reagent. Do not add specimen. Use the same

determination procedures to carry out test, to correct the determination results

as obtained.

4.4 Ignition

Place the filter paper and the precipitate in a crucible which has previously been

burned to a constant weight. To avoid producing flame, in an oxidizing

atmosphere, slowly dry and ash it. After ashing it to the absence of black carbon

particle, then place it in a high-temperature furnace (6.4), to burn it at the

specified temperature. In a desiccator (6.3), cool it to room temperature. Weigh

it.

4.5 Constant weight

After the first burning, cooling, weighing, use the method of applying continuous

burning of 15 min, cooling, weighing, to check the constant mass. When the

difference between two consecutive weighing results is less than 0.0005 g, it

reaches constant weight.

5.1 Hydrochloric acid (HCI)

1.18 g/cm3 ~ 1.19 g/cm3, mass fraction 36% ~ 38%.

5.2 Hydrofluoric acid (HF)

1.15 g/cm3 ~ 1.18 g/cm3, mass fraction 40%.

5.3 Sulfuric acid (H2SO4)

1.84 g/cm3, mass fraction 95% ~ 98%.

5.4 Triethanolamine [N(CH2CH2OH)3]

1.12 g/cm3, mass fraction 99%.

5.5 Hydrochloric acid (1 + 1); (1 + 10)

5.6 Sulfuric acid (1 + 1)

5.7 Triethanolamine (1 + 2)

5.8 Sodium hydroxide (NaOH)

5.9 Anhydrous sodium carbonate

Use an agate mortar to grind the anhydrous sodium carbonate (Na2CO3) finely

ground to a powder form.

5.10 Sodium carbonate-borax mixed flux (2 + 1)

Mix 2 parts by mass of anhydrous sodium carbonate (Na2CO3) and 1 part by

mass of anhydrous borax (Na2B4O7) uniformly and grind it finely. Store it in a

sealed bottle.

5.11 Sodium hydroxide solution (200 g/L)

Dissolve 20 g of sodium hydroxide (NaOH) in water. Add water to dilute it to 100

mL. Store in plastic bottles.

5.12 Potassium hydroxide solution (200 g/L)

Dissolve 200 g of potassium hydroxide (KOH) in water. Add water to dilute it to

5.13 Ammonium molybdate solution (15 g/L)

Dissolve 3 g of ammonium molybdate [(NH4)6Mo7O24 - 4H2O) in 100 mL of hot

water. Add 60 mL of sulfuric acid (1 + 1) and shake it uniformly. After cooling,

add water to dilute it to 200 mL. Store the solution in a plastic bottle. This

solution is used within one week.

5.14 Ascorbic acid solution (50 g/L)

Dissolve 5 g of ascorbic acid (V.C) in 100 mL of water. If necessary, filter it

before use. Prepare it before use.

5.15 pH10 buffer solution

Dissolve 67.5 g of ammonium chloride (NH4Cl) in water. Add 570 mL of

ammonia water (NH3 - H2O). Add water to dilute it to 1 L.

5.16 Sodium potassium tartrate solution (100 g/L)

Dissolve 10 g of sodium potassium tartrate (C4H4KNaO6 - 4H2O) in water. Add

water to dilute it to 100 mL.

5.17 Potassium fluoride dissolution (20 g/L)

Dissolve 20 g of potassium fluoride (KF - 2H2O) in water. Add water to dilute it

to 1 L. Store it in a plastic bottle.

5.18 Preparation of phosphorus pentoxide (P2O5) standard solution

5.18.1 Preparation of phosphorus pentoxide standard solution

Weigh 0.1917 g of potassium dihydrogen phosphate (KH2PO4, reference

reagent) which has been baked at 105 °C ~ 110 °C for 2 h, accurate to 0.0001

g. Place it in a 300 mL beaker. Add water to dissolve it. Transfer it in a 1000 mL

volumetric flask. Use water to dilute it to the mark. Shake it uniformly. Each

milliliter of this standard solution contains 0.1 mg of phosphorus pentoxide.

Pipette 50.00 mL of the above standard solution into a 500 mL volumetric flask.

Use water to dilute it to the mark. Shake it uniformly. Each milliliter of this

standard solution contains 0.01 mg of phosphorus pentoxide.

5.18.2 Drawing of working curve

Pipette 0 mL, 2.00 mL, 4.00 mL, 6.00 mL, 8.00 mL, 10.00 mL, 15.00 mL, 20.00

mL, 25.00 mL of standard solution which contains 0.01 mg of phosphorus

pentoxide per ml into a 200 mL beaker. Add water to dilute it to 50 mL. Add 10

mL of ammonium molybdate solution (5.13) and 2 mL of ascorbic acid solution

(5.14). Heat to slightly boil it for (1.5 ± 0.5) min. After cooling it to room

temperature, transfer it in a 100 mL volumetric flask. Use hydrochloric acid (1 +

10) to rinse the beaker. Use hydrochloric acid (1 + 10) to dilute it to the mark.

Shake it uniformly. Use a spectrophotometer and 10 mm cuvette to determine

the absorbance of the solution at a wavelength of 730 nm, which uses water as

a reference. Use the determined absorbance as a function of the corresponding

phosphorus pentoxide content, to draw the working curve.

5.19 Calcium carbonate standard solution [c(CaCO3) = 0.024 mol/L]

Weigh 0.6 g (m1) of calcium carbonate (CaCO3, reference reagent) which has

been baked at 105 °C ~ 110 °C for 2 h, accurate to 0.0001 g. Place it in a 400

mL beaker. Add about 100 mL of water. Cover the watch glass. Slowly add 5

mL ~ 10 mL of hydrochloric acid (1 + 1) along the mouth of the beaker. Stir it

until all the calcium carbonate is dissolved. Heat the solution to boil. Cool it to

room temperature. Transfer it in a 250 mL volumetric flask. Use water to dilute

it to the mark. Shake it uniformly.

5.20 EDTA standard titration solution [c(EDTA) = 0.015 mol/L]

5.20.1 Preparation of EDTA standard titration solution

Weigh about 5.6 g of EDTA (ethylene diamine tetraacetic acid, C10H14N2O8Na2

- CHO) in a beaker. Add about 200 mL of water. Heat it to dissolve it. Filter it.

Add water to dilute it to 1 L. Shake it uniformly.

5.20.2 Calibration of EDTA standard titration solution's concentration

Pipette 25.00 mL of calcium carbonate standard solution (5.19) into a 400 mL

beaker. Add water to dilute it to about 200 mL. Add appropriate amount of CMP

mixing indicator (5.22). Whilst stirring it, add potassium hydroxide solution (5.12)

until green fluorescence appears. Add another 2 mL ~ 3 mL. Use EDTA

standard titration solution to titrate it until the green fluorescence disappears

and red appears.

The concentration of the EDTA standard titration solution is calculated

according to formula (1).

Where.

c(EDTA) - The concentration of the EDTA standard titration solution, in moles

per liter (mol/L);

V1 - The volume of the EDTA standard titration solution as consumed in

titration, in milliliters (mL);

m1 - The mass of calcium carbonate in the calcium carbonate standard

solution as prepared in accordance with 5.19, in grams (g);

100.09 - The molar mass of CaCO3, in grams per mole (g/mol).

5.20.3 Calculation of titration of each oxide by EDTA standard titration

solution

The titer of EDTA standard titration solution for ferric oxide, aluminum oxide,

calcium oxide, magnesium oxide is calculated according to formula (2), formula

(3), formula (4), formula (5), respectively.

Where.

TFe2O3 - The titer of EDTA standard titration solution for ferric oxide, in

milligrams per milliliter (mg/mL);

TAl2O3 - The titer of EDTA standard titration solution for aluminum oxide, in

milligrams per milliliter (mg/mL);

TCaO - The titer of EDTA standard titration solution for calcium oxide, in

milligrams per milliliter (mg/mL);

TMgO - The titer of EDTA standard titration solution for magnesium oxide, in

milligrams per milliliter (mg/mL);

c(EDTA) - The concentration of the EDTA standard titration solution, in moles

per liter (mol/L);

79.84 - The molar mass of (1/2Fe2O3), in grams per mole (g/mol);

50.98 - The molar mass of (1/2Al2O3), in grams per mole (g/mol);

56.08 - The molar mass of CaO, in grams per mole (g/mol);

40.31 - The molar mass of MgO, in grams per mole (g/mol).

5.21 Calcium carbonate standard titration solution [c(CaCO3) = 0.015

mol/L]

5.21.1 Preparation of standard titration solution

Weigh 1.50 g of calcium carbonate (CaCO3) which has been baked at 105 °C

~ 110 °C for 2 h. Place it in a 400 mL beaker. Add about 200 mL of water. Cover

the watch glass. Slowly add 5 mL ~ 10 mL of hydrochloric acid (1 + 1) along the

mouth of beaker. Stir it until all the calcium carbonate is dissolved. Heat to boil

it for several minutes. Cool the solution to room temperature. Transfer it into a

5.21.2 Calibration of volume ratio of EDTA standard titration solution to

calcium carbonate standard titration solution

Slowly release 10 mL ~ 15 mL EDTA standard titration solution (5.20) from the

burette into a 400 mL beaker. Add about 200 mL of water. Add appropriate

amount of CMP mixing indicator (5.22). Whilst stirring it, add potassium

hydroxide solution (5.12) until a stable red color appears. Add another 2 mL ~

5.22 Calcein - methyl thymol blue - phenolphthalein mixed indicator

(shortly referred to as CMP mixed indicator)

Weigh 1.000 g of calcein, 1.000 g of methyl thymol blue, 0.200 g of

phenolphthalein, 50 g of potassium nitrate (KNO3) which has been dried at

5.23 Acid chrome blue K - naphthol green B mixed indicator (shortly

referred to as KB mixed indicator)

Weigh 1.000 g of acid chrome blue K, 2.500 g of naphthol green B, 50 g of

potassium nitrate (KNO3) which has been dried at 105 °C ~ 110 °C. Mix and

grind it fine. Store it in a mouth-grinding bottle.

5.24 P-nitrophenol indicator solution (2 g/L)

Dissolve 0.2 g of p-nitrophenol in 100 mL of water.

6.1 Balance

It shall not be lower than grade-4, accurate to 0.0001 g.

6.2 Platinum, silver, porcelain crucible

It has a lid. The capacity is 15 mL ~ 30 mL.

6.3 Dryer

It is loaded with color-changing silica gel.

6.4 High-temperature furnace

For the flame-isolated heating furnace, carry out resistance heating on the

periphery of the furnace. It shall use temperature controller to accurately control

the furnace's temperature. The controllable temperature is (950 ± 25) °C.

6.5 Glass capacity vessel

Burette, volumetric flask, pipette.

6.6 Spectrophotometer

It can, within the range of 400 nm ~ 800 nm, determine the absorbance of the

solution. It is equipped with a 10 mm cuvette.

8.1 Summary of method

The specimen is burned in a high-temperature furnace at (950 ± 25) °C, to drive

off carbon dioxide and moisture, while oxidizing the existing oxidizable

elements.

8.2 Analytical procedures

Weigh about 1 g of specimen (m2), accurate to 0.0001 g. Place it in a porcelain

crucible which has been burned to constant weight. Place the lid inclined on the

crucible. Place it in a high-temperature furnace (6.4). From low temperature,

gradually increase the temperature. Burn it at (950 ± 25) °C for 15 min ~ 20 min.

Remove the crucible to place it in a desiccator (6.3). Cool it to room temperature.

Weigh it. Repeat burning, until reaching to constant weight.

8.3 Calculation and representation of results

The mass fraction of the loss on ignition wLOI is calculated according to formula

(7).

Where.

wLOI - The mass fraction of loss on ignition, %;

m2 - The mass of sample, in grams (g);

m3 - The mass of sample after burning, in grams (g).

12.1 Summary of method

In a strong alkaline solution above pH13, use triethanolamine as a masking

agent, use CMP mixed indicator, to add the excess EDTA standard titration

solution for calcium. Use calcium carbonate standard titration solution to back

titrate the excess EDTA dropwise.

12.2 Analytical procedures

Weigh about 0.5 g of specimen (m4), accurate to 0.0001 g. Place it in the silver

crucible. Add 6 g ~ 7 g of sodium hydroxide (5.8). Cover the lid (leave a gap).

Place it in a high-temperature furnace (6.4). Starting from low temperature, melt

it at a high-temperature of 650 °C ~ 700 °C for 20 min, during which time it is

removed and shaken once. Remove to cool it. Place the crucible into a 300 mL

beaker which contains about 100 mL of boiling water. Cover the watch glass.

Heat it slightly on the electric furnace. After the frit is completely leached,

remove the crucible. Use water to rinse the crucible and lid. Whilst stirring it,

add 25 mL ~ 30 mL of hydrochloric acid in one time. Then add 1 mL of nitric

acid. Use hot hydrochloric acid (1 + 5) to clean the crucible and lid. Heat the

solution to boil it. After cooling it, transfer it into a 250 mL volumetric flask. Use

water to dilute it to the mark. Shake it uniformly. This solution A is used for the

determination of calcium oxide (12.2) and magnesium oxide (17.2).

Pipette 25.00 mL of solution from the solution A into a 400 mL beaker. Add 7 mL

~ 10 mL of potassium fluoride (5.17) solution. Add water to dilute it to about 200

mL. Add 5 mL of triethanolamine (1 + 2) and appropriate amount of CMP mixed

indicator (5.22). Whilst stirring it, add potassium hydroxide solution (5.12), until

green fluorescence appears. Add another 5 mL ~ 8 mL. Use the EDTA standard

titration solution [c(EDTA) = 0.015 mol/L] (5.20) to titrate it, until the green

fluorescence disappears and a stable red color appears. Add another 3 mL ~ 5

mL. Place it for 1 min. Then use calcium carbonate standard titration solution

(5.21) to titrate it, until green fluorescence appears.

12.3 Calculation and representation of results

The mass percentage of calcium oxide wCaO is calculated according to formula

(8).

Where.

wCaO - The mass fraction of calcium oxide, %;

TCaO - The titer of EDTA standard titration solution for calcium oxide, in

milligrams per milliliter (mg/mL);

V4 - The volume of EDTA standard titration solution added, in milliliters (mL);

V5 - The volume of calcium carbonate standard titration solution as

consumed by titration, in milliliters (mL);

K1 - The volume ratio of EDTA standard titration solution to calcium

carbonate standard titration solution;

m4 - The mass of the sample in 12.2, in grams (g).

16.1 Summary of method

In a certain acidic medium, phosphorus forms a blue complex with ammonium

molybdate and ascorbic acid. Determine the absorbance of the solution at a

wavelength of 730 nm.

16.2 Analytical procedures

Weigh about 0.25 g of specimen (m5), accurate to 0.0001 g. Place it in a

platinum crucible. Add a small amount of water to wet it, slowly add 3 mL of

hydrochloric acid, 5 drops of sulfuric acid (1 + 1), 5 mL of hydrofluoric acid. Put

it on the hot plate in the fume hood to slowly heat it. When it is almost dry, shake

the crucible, to avoid splash loss. Evaporate it dry. Then add 3 mL of

hydrochloric acid. Continuously place on the hot plate in the fume hood to

evaporate it dry.

After cooling, add 3 g of sodium carbonate-borax mixed flux (5.10) into the

residue which is obtained by hydrofluoric acid treatment. Mix it uniformly. Melt

it at 950 °C ~ 1000 °C for 10 min. Use the crucible tongs to hold the crucible to

rotate it, to make the melt be uniformly attached to the inner wall of the crucible.

After cooling, place the crucible in a 300 mL beaker which contains 10 mL of

sulfuric acid (1 + 1) and 100 mL of water which had been heated to slightly

boiling. Keep it in a slightly boiling state, until the melt is completely dissolved.

Use water to rinse the crucible and lid. After cooling it, transfer it into a 250 mL

volumetric flask. Use water to dilute it to the mark. Shake it uniformly.

Pipette 10.00 mL of the above sample solution into a 200 mL beaker (the

amount of sample solution is determined by the content of phosphorus

pentoxide). Add water to 50 mL. Add 1 drop of p-nitrophenol indicator solution

(5.24). Add sodium hydroxide solution (5.11) dropwise to yellow. Then add

hydrochloric acid (1 + 1) dropwise to colorless. Add 10 mL of ammonium

molybdate solution (5.13) and 2 mL of ascorbic acid (5.14). Heat to slightly boil

it for (1.5 ± 0.5) min. After cooling, transfer it into a 100 mL volumetric flask. Use

hydrochloric acid (1 + 10) to rinse the beaker. Use hydrochloric acid (1 + 10) to

dilute it to the mark. Shake it uniformly. Use a spectrophotometer and 10 mm

cuvette to determine the absorbance of the solution at a wavelength of 730 nm,

using water as a reference. From the working curve (5.18.2), find the content of

phosphorus pentoxide (m6).

16.3 Calculation and representation of results

The mass percentage of phosphorus pentoxide wP2O5 is calculated according

to formula (9).

Where.

wP2O5 - The mass fraction of phosphorus pentoxide, %;

m6 - The content of phosphorus pentoxide in 100 mL solution, in milligrams

(mg);

m5 - The mass of the sample in 16.2 (m5), in grams (g).

17.1 Summary of method

In a solution of pH10, use triethanolamine, sodium potassium tartrate as a

masking agent, use the acid chrome blue K-naphthol chloride B mixed indicator,

use the EDTA standard titration solution for titration.

17.2 Analytical procedures

Pipette 25.00 mL of solution from the solution A into a 400 mL beaker. Add water

to dilute it to about 200 mL. Add 1 mL of sodium potassium tartrate (5.16) and

17.3 Representation of results

The mass fraction of magnesium oxide, wMgO, is calculated according to formula

(10).

Where.

wMgO - The mass fraction of magnesium oxide, %;

TMgO - The titer of EDTA standard titration solution for magnesium oxide, in

milligrams per milliliter (mg/mL);

V6 - The volume of EDTA standard titration solution as consumed in titration

of total calcium and magnesium, in milliliters (mL);

m4 - The mass of the sample in 12.2, in gram (g);

wCaO - The mass fraction of calcium oxide as determined by 12.2, %;

0.7188 - Conversion factor of calcium oxide to magnesium oxide.