GB/T 4701.1-2009 (GB/T4701.1-2009)

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GB/T 4701.1-2009: PDF in English (GBT 4701.1-2009)

NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.100 H 11
GB/T 4701.1-2009
Replacing GB/T 4701.1-1984
Ferrotitanium - Determination of titanium content -
The ammonium ferric sulfate titration method
Issued on. October 30, 2009 Implemented on. May 1, 2010 Issued by. General Administration of Quality Supervision, Inspection and Quarantine of the PRC; Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principles ... 4
4 Reagents and materials ... 5
5 Instruments ... 7
6 Sampling and preparation of samples ... 8
7 Analytical procedures ... 8
8 Calculation of analytical result ... 10
9 Allowable difference ... 11
10 Test report ... 11
Ferrotitanium - Determination of titanium content -
The ammonium ferric sulfate titration method
Caution. The personnel, who use this Part of GB/T 4701, shall have practical experience in laboratory work. This Part does not address all safety problems. It is the responsibility of the user to take appropriate safety and health measures and to ensure compliance with conditions as specified in relevant national regulations.
1 Scope
This Part of GB/T 4701 specifies the determination of titanium content in ferrotitanium using the ammonium ferric sulfate titration method.
This Part applies to the determination of titanium content in ferrotitanium. Measuring range (mass fraction). 20.00%~80.00%.
2 Normative references
The clauses in the following documents, by reference in this Part of GB/T 4701, constitute the clauses of this Part. For the dated references, the subsequent amendments (not including errata content) or revisions do not apply to this Part. However, parties which have reached an agreement according to this Part are encouraged to study whether the latest version of these documents can be used. For the undated references, the latest version is applicable to this Part.
GB/T 4010 Ferroalloys sampling and preparation of samples for chemical
analysis
3 Principles
The sample is dissolved with sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid. If there are chromium, vanadium, molybdenum, and tin interfering elements, in the presence of hydrogen peroxide, the titanium hydroxide can be precipitated to separate from the interfering elements. In a carbon dioxide or nitrogen atmosphere, the titanium is reduced to trivalence with metallic aluminum. USE thiocyanate as an indicator; TITRATE with a standard titration solution of ammonium ferric sulfate; according to the consumption of the standard titration solution of ammonium ferric sulfate, CALCULATE the content of titanium in the sample.
4 Reagents and materials
Unless otherwise stated, in the analysis, only reagents and distilled water identified as analytical purity or water equivalent to the purity shall be used.
4.1 Aluminum, (Al≥99.5%), thickness of 0.10 mm, aluminum foil without titanium. When used, 1 g of aluminum foil is folded to form a rectangle of about 3 cm~4 cm in length and about 1 cm in width.
4.2 Sodium bicarbonate, solid.
4.3 Sulfuric acid, ρ1.84 g/mL.
4.4 Nitric acid, ρ1.42 g/mL.
4.5 Hydrochloric acid, ρ1.19 g/mL.
4.6 Hydrofluoric acid, ρ1.15 g/mL.
4.7 Hydrogen peroxide, ρ1.10 g/mL.
4.8 Sulfuric acid, 1+1.
4.9 Sulfuric acid, 1+4.
4.10 Sodium hydroxide solution, 100 g/L, stored in plastic bottle.
4.11 Sodium hydroxide solution, 20 g/L, stored in plastic bottle.
4.12 Ammonium thiocyanate solution, 100 g/L.
4.13 Nitrogen, oxygen free (oxygen content less than 10×10-6 by volume), purity 99.99%.
4.14 Carbon dioxide, oxygen free (oxygen content less than 10×10-6 by volume), purity 99.99%.
4.15 Ammonium ferric sulfate solution, 35 g/L. WEIGH 35 g of ammonium ferric sulfate [NH4Fe(SO4)2 · 12H2O]; PLACE it in a 400 mL beaker; ADD 100 mL of water and 100 mL of sulfuric acid (1+1); after dissolving, TRANSFER to a 1000 mL volumetric flask; and USE water to dilute to volume, MIX well. This solution contains about 4 mg of iron in 1 mL.
4.16 Titanium standard solution
WEIGH 0.8340 g of titanium dioxide (Ti≥99.9%) which was previously burned at 800 °C for 2 h; PLACE in a platinum crucible with a platinum cover; ADD 10 with a Teflon watch glass; and slowly ADD 5 mL of nitric acid (4.4) to oxidize while cooling. After the reaction is completed, REMOVE the watch glass; HEAT it until sulfuric acid fumes, and CONTINUE to heat for about 5 min; REMOVE and COOL. ADD 30 mL of hydrochloric acid (4.5), and carefully STIR; COVER with the Teflon watch glass; HEAT until the solution is clear. REMOVE, and WASH the watch glass with 5 mL of hydrochloric acid (4.5); after cooling, TRANSFER to a 500 mL volumetric flask; USE water to dilute to volume, and MIX well.
7.3.2 Interfering elements-free
If the content of titanium in the sample is expected to be 20%~45%, PIPETTE
50.00 mL of the test solution (7.3.1). If the content of titanium is 45%~75%, PIPETTE 25.00 mL of the test solution (7.3.1). PLACE the test solution in a 500 mL conical flask; ADD 85 mL of hydrochloric acid (4.5) and 25 mL of water; and PERFORM as specified in 7.3.4 and 7.3.5 or in 7.3.4 and 7.3.6.
7.3.3 Separation of interfering elements
If the content of titanium in the sample is expected to be 20% ~ 45%, PIPETTE
50.00 mL of the test solution (7.3.1). If the content of titanium is 45%~75%, PIPETTE 25.00 mL of the test solution (7.3.1). PLACE the test solution in a 250 mL beaker containing 10 mL of ammonium ferric sulfate solution (4.15); ADD 50 mL of sodium hydroxide solution (4.10) and 2 mL of hydrogen peroxide solution (4.7); HEAT and BOIL for 5 min. After the precipitate sinks, FILTER with double-layer fast filter paper; then TRANSFER all the precipitate to the filter paper; thoroughly WASH the beaker and precipitate 6 times with about 10 mL of sodium hydroxide solution (4.11) each time; and then thoroughly WASH the filter paper and precipitate with sodium hydroxide solution (4.11). WASH the funnel neck with water; then PLACE the funnel on a 500 mL conical flask. ADD 45 mL of hydrochloric acid (4.5) and 15 mL of sulfuric acid (4.9) to the initial 250 mL beaker; and HEAT to 60 °C ~ 70 °C. The mixed acid is added to the filter paper 6 times to dissolve the precipitate (WAIT for the acid to flow away and then ADD another time). WASH the filter paper three times with 35 mL of hydrochloric acid (4.5) at 60 °C ~ 70 °C; and finally WASH the beaker, filter paper, and funnel neck with no more than 40 mL of water at 70 °C ~ 80 °C. PERFORM as specified in 7.3.4 and 7.3.5 or in 7.3.4 and 7.3.6.
7.3.4 Reduction of titanium
ADD 2 g of sodium bicarbonate (4.2) and 4 g of aluminum foil (4.1) to the test solution (7.3.2 or 7.3.3); immediately COVER it with the Bunsen valve or Gai funnel with saturated sodium bicarbonate solution. During the reduction, the solution shall be shaken constantly.
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(Above excerpt was released on 2018-10-19, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
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