Research On Removing Sulfur-bearing Gangue (Barite Type) From Hematite

As the fast development of iron and steel industry, the demand for iron ore is rising year by year,meanwhile the quality request to the steel is also getting more and harsher. steel companys of Various countries reduce Sulfur content in the steel diligently specially iron ore enhances the steel quality. According to the follows principle:The rich iron ore resource is always used firstly.The last is poor,after undergoing many years mining,the high-grade ore resources can be developed is very few, at present the iron ore resources our country is tend to be poor thin and mixed day by day. Desulphurization the sulfur Included in ultrafine low-grade iron ore is a worldwide difficult problem,particularly as the sulfur Included in iron ore by the way of sulfate (BaSO4),the desulphurization is much more difficult,domestic and foreign still have not system's research until now.This topic focused on the problem of desulphurization separation process of hematite contained barite, conducted flotation tests of hematite and barite single mineral adopting single-factor experimental method, meanwhile, researched the floatability mechanism of hematite and barite by means of superficial electric properties, infrared spectrum, adsorptive capacity, angle of contact and so on.The single mineral flotation results indicated:Sodium oleate,oxidized paraffin soap or lauryl sodium sulfate was used as collector in hematite or barite flotation, the yield of hematite and barite is biggest when sodium oleate was used, the oxidized paraffin soap nearly couln't float hematite when the pH was above 6. Humic acid sodium, carboxymethylcellulose or starch was used as depressant in hematite and barite flotation, the depressive effect of the three depressants to hematite was as follows:Humic acid sodium>carboxymethylcellulose>starch. The depressive effect was different with the different dosages, the depressive effect of humic acid sodium was weaker than carboxymet-hylcellulose and starch when the dosage exceeded 2g/t.The results of contact angle measurement of hematite and barite showed that: The pH value has no obvious influence on the contact angle of hematite and barite, the contact angle of hematite and barite has no obvious diference with the variation of pH value. The contact angle of barite increases gradually along with the increment of the collector dosage, the sodium oleate has the most remarkable influence on the contact angle of barite; the contact angle of hematite decreased as the dosage of depressants increased, the humic acid sodium could reduce the contact angle of hematite obviously. Other flotation reagents could increase or decrease the contact angle of barite or hematite in varying degrees.The test results of Zeta potential measurement illustrated that the PH value corresponding to the "zero point" of hematite and barite was about 3.5 and 5.0 respectively; starch could increase the electrokinetic potential of hematite slightly, but other depressants or collectors all reduced the electrokinetic potential of hematite and barite in varying degrees, humic acid sodium reduced the electrokinetic potential of hematite largely. The flotation process of hematite was usually conducted in the neutral or weakly alkaline pulp, the decreasing order of Zeta potential measurement on the surface of hematite treated by various depressants was as follows:Humic acid sodium>carboxymethylcellulose>starch. Under the alkaline condition, the decreasing order of Zeta potential measurement on the surface of barite treated by various collectors was as follows:Sodium oleate>733>lauryl sodium sulfate.The results of adsorption measurements showed that humic acid sodium or starch had a certain adsorption to the surface of hematite, when the dosage of depressant surpassed 2mg/L, the adsorption capacity of humic acid sodium was much bigger than starch, the adsorption capacity of sodium oleate to the surface of barite was much more than oxidized paraffin soap.The FT-IR results showed that there not only found many characteristic vibratory absorption peaks of mineral atom groups but also appeared some of reagents, and the absorption peaks took place in slight displacement. This reflected that the depressants and collectors occurred some degree of chemical aborption and physical abortion to the surface of hematite and barite.According to the single mineral flotation tests, the following conclusions can be obtained:good targets could be obtained when the collector was 733, the depressant was humic acid sodium for the reverse flotation of the hematite(barite type).The real ore separation experiments were conducted, a good desulphurization target was obtained. In the close circuit experiment, the run-of-mine ore contained 1.38% sulfur and 50.13% iron, the concentrate of 60.03% iron and 0.45% sulfur, and the iron recovery of 60.08% was obtained, the recovery of sulfur entered the concentrate was merely 18.54%.