Determination of a content of titanium dioxide, iron titanium ore
1. Measurement principle a. The ilmenite and potassium pyrosulfate melt to form soluble titanium sulfate:
Ti0 2 +4K 2 S 2 O 7 ===Ti(S0 4 ) 2 +4K 2 S0 4 +2S0 3 ↑
. b to aluminum metal with hydrochloric acid Nascent hydrogen:
3HC1+A1===AIC1 3 +3[H]
c. New ecological hydrogen reduces Ti4+ to Ti3+:
[H]+Ti 4+ ===Ti 3+ +H +
. d generated by the reduction orthotitanate Ti 3+ and Ti 3+ solution in the reaction with Fe 3+ ammonium ferric sulfate and the is oxidized to Ti 3+ Ti 4+:
Ti3++Fe3+====Ti4++Fe2+
e. Excess 1 drop of Fe 3+ in ammonium ferric sulfate and thiocyanate to form a stable blood red coordination compound is the end point of titration:
Fe 3+ (excess) + 3CNS-===Fe(CNS) 3 (blood red)
2. Measurement method Accurately weigh 1 g of the ore sample after grinding and drying, place it in a porcelain crucible pre-plated with 9 g of potassium pyrosulfate, and cover 9 g in a muffle furnace. Hold at 300-400 °C for 30-40 minutes to remove the water, then quickly heat up to 700-750 °C for about half an hour, take out when the melt is in a semi-fluid state, and then immerse the person with 100 mL of mixed acid [H 2 SO 4 : HCl: H 2 0 = 10: 5: 85 (volume ratio) in the beaker, heated until the melt completely separated from the crucible, the crucible and the lid were washed with 10% sulfuric acid, and after the molten salt was completely dissolved, it was cooled and transferred. In a 250 mL volumetric flask, dilute to the mark with water and shake to a titanium solution A.
Pipette the above titanium solution A 25mL, into a 500mL conical flask, add concentrated hydrochloric acid 25mL, aluminum sheet 2. 0g, install the liquid sealing tube, add saturated sodium bicarbonate solution, put it on the electric stove slowly After heating, until the aluminum sheet is completely in effect, continue to heat until the solution bubbles. At this time, the solution is clear and transparent purple. Remove it and cool it to room temperature with cold water, open the liquid sealing tube, and quickly pour the appropriate amount of saturated sodium bicarbonate solution. Immediately with 0. lmol / L high-iron ammonium sulfate solution titrated to purple disappear, add 40% thiocyanate 2mL as an indicator, continue to titrate until the solution is brownish yellow does not disappear in half a minute is the end.
3. Calculation
Wherein the mass fraction of ωTiO 2 ----Ti0 2 , %;
c[NH 4 Fe(S0 4 ) 2 ] - the concentration of the substance of the standard concentration of ammonium ferric sulfate, mol / L;
V—volume the volume of the ammonium ferric sulfate solution, mL;
V 1 - the volume of titanium liquid A is taken up, mL;
V 2 — the volume of the total volume of the titanium solution A, mL;
M—the quality of the sample when weighing titanium A, g;
The molar mass of 0.0799 titanium dioxide, kg / mol. [next]
2. Determination of total iron content in ilmenite
1. The measurement principle Fe 3+ in a hot hydrochloric acid, reduced to Fe 2+ with stannous chloride:
2Fe 3+ +Sn 2+ ===2Fe 2+ +Sn 4+
b. Adding chlorinated high mercury to remove excess stannous chloride to form a silvery mercuric chloride precipitate:
2HgCl 2 +SnC1 2 ===SnC1 4 +Hg 2 C1 2 ↓(silver filament)
Since the redox potential of HgC1 2 /Hg 2 C1 2 is smaller than Fe 3+ /Fe 2+ and larger than the redox potential of Sn 4+ /Sn 2+ , chlorinated high mercury cannot oxidize Fe 2+ but only oxidizes Sn 2+ .
c. Fe 2+ after reduction, oxidation with chromium weight potassium titrated to Fe 3+ excess potassium dichromate solution one drop of diphenylamine sulfonate represented purple indicator reaches the end of the oxidation.
6Fe 2+ +(Cr 2 O 7 ) 2 -+14H + ===6Fe 3+ +2Cr 3 ++7H 2 O
2. Determination method Pipette titanium solution A25mL into a 30mL conical flask, rinse the wall with a small amount of water, add 10mL of concentrated hydrochloric acid, heat to boiling, add 10% stannous chloride solution to yellow just disappear, 5æ‘©å°”1/é‡çš„é‡é“¬ã€‚ Adding 1-2 drops of cold water to room temperature, adding 10% of 4% chlorinated high-mercury solution, 2 minutes, adding 4 drops of 1% aqueous solution of diphenylamine sulfonate, with 0. 05mo1/L of heavy chromium Potassium acid standard solution
1. Determination principle In the case of avoiding contact with air, ilmenite is treated with hydrochloric acid and hydrofluoric acid, ferrous iron is still dissolved in solution in divalent state, sodium diphenylamine sulfonate is used as indicator, and dichromic acid is used. Potassium standard solution was titrated to purple as the end point.
6FeC1 2 +K 2 Cr 2 O 7 +14HC1===6FeC1 3 +2CrCl 3å 2KC1+7H 2 O
Titration before addition of boric acid, a large amount of fluorine ions object complex compound solution, to remove excess fluoride ion interference, and this complex can float on top solution, from the seal action.
The sulphate of sodium sulphate, 0.5 g of sodium bicarbonate, 0.5 g of sodium bicarbonate, with a small amount Wet with water, add 30mL of concentrated hydrochloric acid, shake well, disperse the sample in the bottom of the bottle, quickly plug the rubber stopper with capillary or slit rubber tube, carefully heat to make it slightly boiling, until the sample is completely decomposed, leave The heat source, quickly pour 10 mL of boric acid and about 0. 5-1 g of sodium bicarbonate and about 30 mL of boiled cold distilled water, rapidly cooled to room temperature with cold water, add 4 drops of sodium diphenylamine sulfonate (0.5%), with 0.05 mol1 /L potassium dichromate standard solution [next]
4. Determination of fineness of ilmenite powder
The method for determining the fineness of ilmenite powder is as follows: accurately weigh about 10g (accurate to 0. OOlg) ore powder, place it on a small standard sieve with a constant mass of 49μm, rinse with running water, and light with a soft brush. Brush the sample until there is no black. Then, it was baked at 105-110 ° C for 1 h, taken out and cooled in a desiccator for 30 min, and then baked for half an hour and then weighed until the mass was constant. The difference in mass before and after drying is the quality of the sieve residue.
Where A - standard sieve + sieve residue quality, g;
B—the quality of the standard sieve, g;
M-sample quality, g.
The standard screen common mesh number and mesh number are shown in the table below.
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