GOST 8775.3-87

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  ГОСТ 8775.3-87

GOST 8775.3−87 Li. Method for the determination of magnesium, manganese, iron, aluminum, silicon, barium

GOST 8775.3−87

Group B59

STATE STANDARD OF THE USSR

LI

Method for the determination of magnesium, manganese, iron, aluminum, silicon, barium

Lithium.
Method for determination or magnesium, manganese, iron, aluminium, silicon, barium

AXTU 1709

Valid from 01.07.88
to 01.07.93*
__________________________
* Limit of validity
based on a Protocol of Intergovernmental
Council for standardization, Metrology
and certification (I & C N 2, 1993). -
Note the manufacturer’s database.

INFORMATION DATA

1. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 28.09.87 N 3764

2. The term of the first test 1991

The frequency of inspection 5 years

3. REPLACE GOST 8775−75 (sect.4)

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard establishes a spectral method for the determination of impurities of magnesium, manganese, iron, aluminum, silicon, barium when the mass fraction of magnesium from 0.002 to 0.05%, manganese from 0.01 to 0.0003%, iron from 0.002 to 0.04% aluminum 0.001 to 0.04%, silicon is from 0.003 to 0.04%, barium from 0.003 to 0.04% in lithium.

The method is based on excitation of emission spectra of magnesium, manganese, iron, aluminum, silicon, barium and recording their photographic or photoelectric methods.

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 8775.0−87.

2. APPARATUS, REAGENTS AND MATERIALS

The type of spectrograph DFS-8, DFS-13, ES-28, ES-30 or quantometer type DFS-36.

The arc type generator UGE-4 or other excitation source with the same or better metrological characteristics.

Microphotometer type MF-2 or microdensitometer type MD-100.

Laboratory scales according to GOST 24104−80* 2nd accuracy class with the largest weighing limit of 200 g.
______________
* On the territory of the Russian Federation GOST 24104−2001. — Note the manufacturer’s database.

The measuring device of any design of stainless steel according to GOST 5632−72 or organic glass according to GOST 17622−72, plenty of hanging mass (10±2) mg.

Cups made of Zirconia or glass.

Pestle made of organic glass.

Cup platinum according to GOST 6563−75 with a capacity of 100 cm.

Use a glassy carbon dishes.

Vibrator for grinding of samples and calibration samples of any design on the base of the vibrator IV-104, which provides the rotation speed of not lower than 1400 min.

Boxing protective organic glass according to GOST 17622−72.

Knife stainless steel according to GOST 5632−72.

The unit according to GOST 14919−83.

The shaped electrodes of type I and type IV stamps high purity-7−4.

Allowed to apply the electrodes (Fig.1, 2) made from the embers of the brand high purity-7−3 and other brands to ensure the required cleanliness for specific items.

Damn.1. Photographic registration of spectrum

Photographic registration of spectrum

Damn.1

Damn.2. Photoelectric registration of spectrum

Photoelectric registration of spectrum

Damn.2

Tools for compacting the sample in the crater of the lower electrode (see the devil.1, 2).

Records of the photographic type I, slide or other for normal blackening of analytical lines.

Lamp type SVD-500.

Ammonia water according to GOST 3760−79.

Ammonium carbonate according to GOST 3770−75, a saturated solution or a solution of carbonate of ammonium, prepared by saturation of 25% aqueous ammonia solution with carbon dioxide in plastic container.

Lithium carbonate, the OS. h or prepared according to the application.

Magnesium oxide according to GOST 4526−75.

Manganese oxide according to GOST 4470−79.

Iron oxide.

Aluminum oxide, H. h

Silicon dioxide according to GOST 9428−73.

Barium carbonate according to GOST 4158−80.

Carbon tetrachloride according to GOST 20288−74.

Metalhydrogen developer of the following composition:

Distilled water GOST 6709−72, double-distilled in quartz apparatus.

Rectified ethyl alcohol GOST 18300−87 or GOST 5962−67*.
______________
* On the territory of the Russian Federation GOST R 51652−2000. — Note the manufacturer’s database.

3. PREPARATION FOR ASSAY

3.1. Preparation of samples for calibration

The initial mixture for the preparation of samples for calibration, containing 1% of magnesium, manganese, iron, aluminum, silicon, and barium from the sum of the mass fraction of lithium and the determined elements, is prepared as follows: in the platinum Cup is placed 9,9371 g lithium carbonate (base), 0,0331 g of magnesium oxide, 0,0316 g of manganese oxide, 0,0286 g of iron oxide, 0,0378 g of aluminium oxide, 0,0428 g of silicon dioxide and 0,0287 g barium carbonate, suspended with an error of less than 0.0005 g, and ground manually with a pestle for at least 3 h.

Allowed to enter into the initial mixture of other elements (not more than 1% each) without changing the mass fraction of magnesium, manganese, iron, aluminum, silicon and barium.

Prepared the initial mixture is stored in tightly sealed plastic jar.

Samples for calibration (TH), with a mass fraction of detectable elements from the 0.0003 to 0.3% of the amount of lithium and impurities, prepare a serial dilution of the starting mixture or to the appropriate model for the calibration lithium carbonate (a base) in accordance with the table.1.

Table 1

Mass fraction of magnesium, manganese, iron, aluminum, silicon and barium in the samples for calibration are corrected by summing the mass fraction of the element introduced into the sample contained in the basis. Preparation of a basis and determination of the impurities in the basis given in the Appendix.

Grind samples for calibration for at least 3 h, manually or on a vibrator for 60 min in cups made of Zirconia or glass, when you RUB it pour about 5 cmof ethyl alcohol.

Prepared samples for calibration stored in tightly sealed polyethylene banks.

3.2. Preparation of samples for analysis

Pieces of lithium metal stored in accordance with GOST 8774−75, remove from the jar with tweezers, degreased with carbon tetrachloride, cleaned with a knife from the oxides and on the plate of organic glass cut from each piece of the required amount of metal to total mass was approximately 1 g.

The lithium sample mass 1.0 g is dissolved in 30−40 cmof water, poured into a platinum Cup, with each piece of the lithium introduced into the Cup after the dissolution of the previous one. Pour the 30−40 cmof a saturated solution of carbonate of ammonium. The solution is evaporated to dryness on the hot plate or under a lamp SVD-500. The obtained lithium carbonate is ground with a pestle in the Cup for 5−10 min and poured into a quartz test tube with a cork or a pack of tracing paper.

For the mass concentration of determined elements more than 0.3% of the sample before analysis was diluted ten times in platinum or glassy carbon Cup place 0,100 g of the sample in the form of lithium carbonate and of 0.900 g the basics and pound with the pestle for 20 min or 10 min on a vibrator.

4. ANALYSIS

4.1. Analyzed a sample prepared according to claim 4.2, and each sample for calibration, prepared according to claim 4.1, weighing about 10 mg, fill the dipstick to the crater bottom electrode and compacted.

The upper electrode is a graphite electrode, sharpened to a cone.

Prepare three sample electrode and three electrodes of each of the calibration sample (TH).

If necessary, the electrodes before analysis is fired in arc DC at a current of 12 A for 15 seconds.

4.2. Analysis with photographic registration of spectra

4.2.1. Spectra of the samples and excite the arc of DC with the following parameters: rated current 12 A, the exposure time of 90 s, in the interelectrode gap of 2 mm, the wavelengths of the analytical lines listed in table.2.

Table 2

Note. Allowed to use other analytical lines and background that provides the reproducibility of the analysis.

4.2.2. Photographic plates showing, fixed, washed and dried.

On each spectrogram photometric the blackening of analytical lines and background in the short wavelength direction from the line, measure the difference pucherani analytical lines and background (). On three values , , obtained three spectrograms for the sample and for each, calculate the average arithmetic value .

According to the results of photometry, GO to build calibration graphs by laying the abscissa shows the logarithm values of the mass fraction of the element in the calibration sample, in percent (tab.1), and on ordinate axis — the arithmetic average of the calibration sample.

4.2.3. The result of the determination (mass fraction of the element in percent) find the calibration schedule using the arithmetic mean of the sample.

4.3. Analysis by the photoelectric spectra

4.3.1. Evaporation of the samples and the excitation spectrum is carried out in the arc of DC, the exposure time of 60 s, current 16 And in the interelectrode gap of 3 mm, the width of the entrance slit of 15−25 µm, exit slit width and wavelengths of the analytical lines listed in table.3.

Table 3

4.3.2. With a digital voltmeter quantometer shoot for trial and for each, the readings are proportional to the logarithms of the relationship of the intensities of the analytical lines and background (). On three values , , calculate the arithmetic mean () for sample and each.

According to the indications of the digital voltmeter quantometer to GO build calibration graphs by laying the abscissa shows the logarithm values of the mass fraction of the element in the calibration sample, in percent (tab.1), and on ordinate axis — the arithmetic mean of three measurements of the calibration sample.

4.3.3. Mass fraction of the element in percent find the calibration schedule using the arithmetic mean of the sample.

5. PROCESSING OF THE RESULTS

5.1. For the result of the determination take mass fraction of the element obtained according to claim 4.2.3, with photographic registration and according to claim 4.3.3, with the photoelectric registration of spectrum.

5.2. For the results analysis be the arithmetic mean of two parallel definitions (some definitions) under the conditions of the PP.2.5, 2.6, and 2.10 GOST 8775.0−87.

5.3. Accuracy metrics

5.3.1. The relative standard deviation of repeatability of the results of parallel measurements () — not more than 0,20.

5.3.2. The relative standard deviation of reproducibility of results definitions () not more than 0,20.

5.3.3. Non-excluded systematic error () is insignificant compared to the random error ().

5.3.4. The value of uncertainty analysis results () is determined according to GOST 8775.0−87.

5.4. Mass fraction of silicon in terms of silicon oxide is calculated by multiplying the found mass fraction of silicon by 2.14.

5.5. The control accuracy of the analysis

The control accuracy of the analysis carried out by the method of additives in accordance with GOST 8775.0−87, using as additives GO of the determined elements or mounting of these elements in the form of oxides. The addition of the element is added to the weighed sample until it is dissolved.

APP (mandatory). PREPARATION OF SPECTRAL-PURE LITHIUM CARBONATE

APP
Mandatory

1. Apparatus, reagents and solutions

Buchner funnel according to GOST 9147−80.

Laboratory filter paper according to GOST 12026−76.

Filters paper, blue tape.

The unit according to GOST 14919−83.

Drying Cabinet.

Water bidistilled.

Of lithium hydroxide.

Ammonia water according to GOST 3760−79.

Ammonium oxalate according to GOST 5712−78, saturated solution.

Ammonium carbonate according to GOST 3770−75, saturated solution.

Hydrochloric acid by the GOST 3118−77, distilled or GOST 14261−77.

Salt diamontina Ethylenediamine — N, N, N, N — tetraoxane acid, 1-water, solution of concentration 500 g/DMor prepared as follows: 250 g of disodium salt Ethylenediamine — N, N, N, N — tetraoxane acid (Trilon B) according to GOST 10652−73 dissolved in 500 cmof hot water and filtered on a Buechner funnel through a paper filter. To the filtrate while stirring pour the hydrochloric acid until then, until you stop the flow of sediment. Solution to precipitate Ethylenediamine — N, N, N, N — tetraoxane acid is cooled and filtered on a Buechner funnel through a paper filter.

The precipitate is dissolved in hot water and repeat the operation of acid deposition and filtration. Filtered Ethylenediamine — N, N, N, N — tetraoxane acid transferred to the beaker, which add ammonia solution till the odor. The resulting solution was filtered through a glass filter and bring the volume of the filtrate with water to 500 cm.

Silver nitrate according to GOST 1277−75, 0,1% solution.

Acetone according to GOST 2603−79.

The technical rectified ethyl alcohol according to GOST 18300−72, the highest grade.

Hydrogen peroxide according to GOST 1092

9−76.

2. Obtaining purified lithium carbonate from lithium hydroxide

A portion of lithium hydroxide with a mass of 0.1−1 kg placed in a beaker, moistened with water, poured 5cmof hydrogen peroxide and hydrochloric acid to slightly acid reaction. The hot solution is neutralized with ammonia solution, poured 5−10 cmof a saturated solution of carbonate of ammonia, mix and leave for a day. After settling, the solution was filtered through a Buchner funnel. The filtrate is heated to boiling, add 40−50 cmof a solution of ammonium oxalate, mix and leave for a day. The solution was filtered through a Buchner funnel. To the filtrate add 80−100 cmsolution giammarino salt Ethylenediamine — N, N, N, N — tetraoxane acid, heated to boiling, add a saturated solution of ammonium carbonate until cessation of precipitation of lithium carbonate, stirred and allowed to settle. After settling, the solution is decanted and to the residue lithium carbonate poured boiling water, stirred, defend 15−20 minutes and the water is drained. The precipitate is washed with water at least three times, and then poured to the residue ethanol (one volume of sludge requires two volume of ethanol), stirred, allowed to stand for 30−40 min and the alcohol decanted, poured to the residue acetone (in a volume of sediment required one volume of acetone), mix and leave for a day. After settling, the precipitate is filtered on a Buechner funnel, washed with acetone until no chlorine ions in the wash liquid (sample with solution of nitrate of silver). After which the precipitate was poured onto a sheet of tracing paper, and dried in a fume hood for approximately one day at room temperature, and then in a drying Cabinet at a temperature of 100−110 °C to constant weight. Dry lithium carbonate is placed in a plastic jar and close lid tightly.

3. Quality control lithium carbonate (base)

The quality of the lithium carbonate test of the spectral method. To do this, prepare a set of compounds in accordance with clause 4.1 of this standard.

Prepared mixture and analyze on the basis of sec. 5. Using the prepared blends as samples for calibration, build of the calibration graphs.

Mass fraction of the element in the basis was determined by linear extrapolation or a method of successive approximations. The Foundation is considered usable if the mass fraction of manganese does not exceed 3.0·10%, magnesium, iron, aluminum, silicon, barium — not more than 1.0·10% each.