GOST 1219.1-74
GOST 1219.1−74 calcium Babbits. Method for the determination of calcium content (with Amendments No. 1, 2)
GOST 1219.1−74
Group B59
INTERSTATE STANDARD
CALCIUM BABBITS
Method for the determination of calcium content
Lead-calcium bearing alloys.
Method for determination of calcium content
ISS 77.120.60
AXTU 1709
Date of introduction 1975−01−01
The decision of the State standards Committee of the Council of Ministers of the USSR from January 17, 1974 N 150 date of introduction is established 01.01.75
Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)
REPLACE GOST 1219−60 in part of sec. II
EDITION (September 2003) with Changes No. 1, 2 approved in November 1979 and November 1984 (IUS 1−80, 2−85).
This standard applies to calcium babbits and sets the volume complexometric method for the determination of calcium content (in mass percentage of calcium, from 0.2 to 1.50%).
The method is based on the ability of calcium ion to form in the alkaline environment of a colorless chelate compound with Trilon B.
To establish the endpoint of the titration used metallindustri that form with the designated colored ion complexes are less durable than the corresponding complex of this ion with Trilon B. At the end point of the titration (with full binding in the complex ion titrated with Trilon B) the solution is painted in the color inherent to the free indicator.
Preventing the components of alloy is removed by successive precipitation by sodium sulfate and sodium sulfide.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 1219.0−74.
2. REAGENTS AND SOLUTIONS
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Nitric acid GOST 4461−77 diluted 1:1.
Sodium sulfate according to GOST 4166−76, 20% solution.
Sodium sulfide according to GOST 2053−77, 5% solution.
Sodium hydroxide according to GOST 4328−77, 5% solution.
Ammonia water according to GOST 3760−79.
Ammonium chloride according to GOST 3773−72.
Sodium chloride according to GOST 4233−77.
Zinc GOST 3640−94 brand C0, 0.025 M solution; prepared as follows: 1,6343 g of zinc is dissolved in 15 cmof hydrochloric acid diluted 1:1, transferred into a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
Ammonia buffer solution; prepared as follows: 20 g of ammonium chloride dissolved in water, adding 100 cmof water of ammonia and dilute with water to 1 DM
.
Indicator eriochrome black T; is prepared as follows: 0.1 g of the indicator is triturated with 10 g of sodium chloride.
Trilon B (III chelating agent, disodium salt of ethylenediaminetetraacetic acid) according to GOST 10652−73, titrated 0,025 M solution; prepared as follows: 9.3 g Trilon B dissolved in water, the solution transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.
Indicator murexide (ammonium salt purple acid); prepared as follows: 0.1 g of murexide thoroughly mixed with 10 g of sodium chloride.
Indicator of acid chrome dark blue, 1% aqueous solution.
Indicator methylorange paper.
The installation of the titer of 0.025 M solution of Trilon B
The titer of the solution Trilon B is set at 0.025 M solution of zinc chloride. Put 20 cmof zinc chloride in conical flask, add 100 cm
of water 15 cm
buffer mixture and 0.05−0.1 g of the indicator erichrome black So Obtained violet solution titrated with a solution of Trilon B till the transition of color in blue without the purple tint.
The titer of the solution Trilon B (), expressed in g/cm
calcium, calculated by the formula
where — the amount of calcium corresponding to 1 cm
of 0.025 M solution of Trilon;
— the volume of 0,025 M solution of zinc, cm
;
— volume of solution Trilon B, spent on titration, sm
.
(Changed edition, Rev. N 1, 2).
3. ANALYSIS
3.1. During the titration with the indicator murexide (for brands of BKA and BK2)
3.1.1. A portion of the babbit 2 g were placed in a glass with a capacity of 250−300 cm, dissolved in 15 cm
of nitric acid by slow heating and boil to remove oxides of nitrogen.
Dissolve salt in 30−40 cmof water and add 20 cm
of a solution of sulphate of sodium. Sediment is allowed to settle for 20 min, after which it is filtered off on a double ashless filter medium density, on which is placed a small amount of paper pulp made from ash-free filter. Precipitate was washed in the flask and on the filter 3−4 times with cold water and drop.
To the filtrate dropwise poured the sodium sulphide solution until cessation of precipitation of sulfur compounds (the reaction medium should remain acidic, otherwise the solution it is necessary to acidify a small quantity of hydrochloric acid diluted 1:1). Sediment is allowed to settle for 10−15 minutes and then filtered on ash-free filter medium density, on which is placed a small quantity of paper pulp. Flask in which to carry out the deposition, and the filter with the precipitate is washed 3−4 times with cold boiled water.
(Changed edition, Rev. N 1).
3.1.2. The filtrate and the washings collected in a conical flask with a capacity of 500 cm. The filtrate is heated to boiling, which is maintained for 40 min, cooled, placed in the flask a small piece of paper methylorange and neutralize the sample with sodium hydroxide solution.
Then add 5 cmof sodium hydroxide solution, 0.05−0.1 g of the indicator of murexide (before the formation of bright red staining solution) and titrated 0,025 m solution of Trilon B to change the color of the solution from red to purple, not changing from further perelivania Trilon B.
At the same time through all stages of the analysis carried out control experience in the determination of calcium content in the reagents.
(Changed edition, Rev. N 1).
3.2. During the titration indicator acid chrome dark blue (Babbitt stamps BKA)
Dissolution of the sample babbit and further operations are performed as specified in claim , heated to boiling, which is maintained for 10 min, cooled, placed in the flask a small piece of paper methylorange, neutralize 25% aqueous ammonia solution and poured 10 cm
of ammonia in excess. Add a few drops of indicator solution of acid chrome dark blue and titrate 0,025 m solution of Trilon B to change the color of the solution from red with a purple hue to a pure blue.
At the same time through all stages of the analysis carried out control experience in the determination of calcium content in the reagents.
4. PROCESSING OF THE RESULTS OF THE ANALYSIS
4.1. Mass fraction of calcium () in percent is calculated by the formula
where the titer of the solution Trilon B, expressed in g/cm
calcium;
— number of Trilon B solution, consumed for titration of sample solution, cm
;
— the number of solution Trilon B, used for titration of the reference experiment, cm
;
— hanging Babbitt, g
.
4.2. Allowable absolute differences between the extreme results of the analysis of not more than 0.03% when the mass fraction of calcium from 0.2 to 0.6%; a 0.05% for the mass concentration of calcium of more than 0.6 to 1.5%.
(Changed edition, Rev. N 1).
