GB/T 210.2-2004Specification and determination methods of sodium carbonate for industrial use -- Part 2: Specification and determination methods (English PDF)

3.1 Safety tips

Some of the reagents used in this test method are toxic or corrosive. Be

cautious during operations! If splashing on the skin, FLUSH immediately.

In severe cases, TREAT immediately.

3.2 General provisions

In the absence of other requirements specified, the reagents and water used in

this Standard refer to analytical reagents and Level III water specified in GB/T

6682-1992

3.3 Determination of total alkali content

3.3.1 Method summary

USE bromocresol green-methyl red mixture as indicator. USE standard

hydrochloric acid volumetric solution for the titration of total alkali content.

3.3.2 Reagents

3.3.3 Analysis procedures

3.4 Determination of chloride content

3.4.1 Mercurimetric method

3.4.1.1 Method summary

Same as the method in the Chapter 2 of GB/T 3051-2000.

3.4.1.2 Reagents

3.4.1.3 Instrument

3.4.1.3.1 Burette. The division value is 0.02mL or 0.05mL.

3.4.1.4 Analysis procedures

3.4.2.3 Instruments

3.4.2.3.1 Potentiometer. The accuracy shall not be lower than 10 mV/cell. The

range shall be (-500 ~ +500) mV.

3.4.2.3.2 Reference electrode. double liquid junction saturated calomel

electrode, filled with saturated potassium chloride solution. During titration, the

saturated potassium nitrate solution filled in the outer casing shall be connected

with the calomel electrode.

3.4.2.3.3 Measuring electrode. silver electrode or silver electrode with silver

sulfide coating (For the preparation method, SEE the Appendix A of GB/T 3050-

2000).

3.4.2.3.4 Burette. The division value is 0.02mL or 0.05mL.

3.4.2.4 Analysis procedures

WEIGH appropriate quantity of test samples (2g of Type I, 1g of Type II).

ACCURATE to 0.01g. PLACE the test samples in a 100mL beaker. ADD 40mL

of water for dissolution. MAKE the following operations according to the

provisions in the Section (3.4.2.2.2). START from "PUT in electromagnetic

stirrers" to "NOTE down a potential value E again after the endpoint". However,

do NOT add 4.00mL of standard silver nitrate volumetric solution at a time first.

In the meantime, CONDUCT the blank test.

3.4.2.5 Result calculation

The chloride content shall be counted as the mass fraction of sodium chloride

(NaCl) w2.The numerical values shall be expressed as %. CALCULATE

according to the Equation (5).

3.5 Determination of iron content

3.5.1 Method summary

Same as the method in the Chapter 2 of GB/T 3049-1986.

3.5.2 Reagents

Same as the reagents in the Chapter 3 of GB/T 3049-1986.

3.5.3 Instruments

3.5.3.1 Spectrophotometer. It has an absorption cell with the thickness of 3cm.

3.5.4 Analysis procedures

3.5.4.1 Drawing of the working curve

According to the provisions in the Section 5.3 of GB/T 3049-1986, SELECT the

absorption cell with the thickness of 3cm and the corresponding consumption

of standard iron solution. DRAW the working curve.

3.5.4.2 Determination of test samples

WEIGH 10g of test samples. ACCURATE to 0.01g. PLACE them in a beaker.

ADD small amount of water for wetting. Dropwise ADD 35mL of hydrochloric

acid solution (1+1). BOIL for (3~5) min. After cooling (FILTRATE if necessary),

TRANSFER the solution into a 250mL volumetric flask. ADD water to the scale.

SHAKE evenly.

3.6 Determination of sulfate content

3.6.1 Barium sulfate gravimetric method & arbitration method

3.6.1.1 Method summary

DISSOLVE the test sample. SEPARATE the insoluble substances.

PRECIPITATE the sulfate as barium sulfate in dilute hydrochloric acid medium.

SEPARATE the obtained precipitations. BURN at (800 ± 25) °C. WEIGH

afterwards.

3.6.1.2 Reagents

3.6.1.2.1 Ammonia;

3.6.1.2.2 Hydrochloric acid solution. 1+1;

3.6.1.2.3 Barium chloride solution. 100 g/L;

3.6.1.2.4 Silver nitrate solution. 5 g/L;

USE small amount of water to dissolve 0.5g of silver nitrate. ADD 20ml of nitric

acid solution (1+1). USE water to dilute to 100mL. SHAKE evenly.

3.6.1.2.5 Methyl orange indicator solution. 1 g/L.

3.6.1.4 Result calculation

The sulfate content shall be counted as the mass fraction of sulfate radical (SO4)

w4.The numerical values shall be expressed as %. CALCULATE according to

the Equation (7).

3.6.2 Barium sulfate turbidimetry

3.6.2.1 Method summary

In slightly acidic medium, USE barium chloride to precipitate sulfate ions.

COMPARE with standard barium sulfate turbidimetric liquid.

3.6.2.2 Reagents

3.6.2.2.1 Barium chloride solution. 250 g/L;

3.6.2.2.2 Standard sulfate solution. 1mL of standard sulfate solution contains

0.1mg of sulfate radical (SO4);

After preparing according to HG/T 3696.2, accurately DILUTE 10 times.

3.6.2.2.3 Phenolphthalein indicator solution. 10 g/L.

3.6.2.3 Analysis procedures

WEIGH (1.00 ± 0.01) g of test samples. PLACE them in a 250mL beaker. ADD

20mL of water and 1 drop of phenolphthalein indicator solution. Dropwise ADD

hydrochloric acid solution (3.6.1.2.2), until the phenolphthalein changes color.

ADD excessive 2mL. BOIL for 2min. After cooling (FILTRATE if necessary),

TRANSFER the solution into a 50mL colorimetric tube.

3.7 Determination of water insoluble substances

3.7.1 Method summary

DISSOLVE the specimens in the water at (50 ± 5) °C. FILTRATE, WASH, DRY

and WEIGH the insoluble substances.

3.7.2 Reagents and materials

3.7.2.1 Phenolphthalein indicator solution. 10 g/L.

3.7.2.2 Acid-washed asbestos. TAKE appropriate amount of acid-washed

asbestos. SOAK it in hydrochloric acid solution (1+3). BOIL for 20min. USE a

Buchner funnel for filtration. WASH the acid-washed asbestos until it becomes

neutral. USE 100g/L anhydrous sodium carbonate solution for soaking. BOIL

for 20min. USE a Buchner funnel for filtration. WASH the acid-washed asbestos

until it becomes neutral (USE phenolphthalein indicator solution for testing).

USE water to prepare into paste for standby application.

3.7.2.3 Asbestos filter paper.

3.7.3 Instruments

3.7.3.1 Gooch crucible. The volume is 30mL.

3.7.4 Crucible preparation

3.7.6 Result calculation

The mass fraction of water insoluble substances shall be counted as w5.The

numerical values shall be expressed as %. CALCULATE according to the

Equation (9).

3.8 Determination of loss on ignition

3.8.1 Method summary

HEAT the specimens at (250~270) °C to constant weight. During heating, LOSE

free water and sodium bicarbonate, and thus DISCOMPOSE into water and

carbon dioxide. CALCULATE the loss on ignition.

3.8.2 Instruments

3.8.2.1 Phi30mm × 25mm weighing bottle or porcelain crucible with the volume

of 30mL or so.

3.8.3 Analysis procedures

WEIGH about 2g of test samples. ACCURATE to 0.000 2g. PLACE them in a

weighing bottle or porcelain crucible in constant weight at (250~270) °C.

TRANSFER into a drying oven or high temperature furnace. HEAT at

(250~270) °C to constant weight.

3.9 Determination of bulk density

3.9.1 Method summary

A certain quantity of specimens enter into a cylindrical specimen tank with a

known volume through a conical funnel. DETERMINE the mass of the

specimens needed for filling up the specimen tank.

3.9.2 Instruments

3.9.3 Analysis procedures

INSTALL the measuring device of bulk density according to Figure 1.WEIGH

the mass of the specimen tank. ACCURATE to 1g. CLOSE the bottom of the

funnel, so as to naturally fill the funnel with test samples. USE a ruler to scrape

the higher part. KEEP the specimen tank with known mass well. OPEN the

bottom of the funnel so that the specimens automatically flow into the specimen

tank. USE a ruler to scrape the higher part (Do NOT move the specimen tank

before levelling). WEIGH the masses of the specimens and the specimen tank.

ACCURATE to 1g.

3.9.4 Result calculation

The bulk density shall be counted as the mass of the unit volume rho. The

numerical values shall be expressed as gram per milliliter (g/mL). CALCULATE

according to the Equation (12) below.

3.10 Determination of granularity

3.10.1 Instruments

3.10.2 Analysis procedures

WEIGH about 50g of test samples. ACCURATE to 0.1g. PLACE them in the

test sieve equipped with sieve bottom. COVER the sieve lid. Manually SHAKE

the sieve in a horizontal direction for 2min. VIBRATE 80 times per minute. Or

USE a sieve shaker to sieve for 5min. WEIGH the mass of the residues on sieve.

ACCURATE to 0.1g.

3.10.3 Result calculation

The mass fraction of the residues on sieve shall be counted as w6.The

numerical values shall be expressed as %. CALCULATE according to the

Equation (13).

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