The effect of biochar substituted for anthracite as reductant on magnetizing-roasting pyrite cinder was in- vestigated. The key of magnetizing-roasting is the gasification reaction between reductants and CO2. Since bi...The effect of biochar substituted for anthracite as reductant on magnetizing-roasting pyrite cinder was in- vestigated. The key of magnetizing-roasting is the gasification reaction between reductants and CO2. Since biochar could react with CO2 more rapidly at lower temperature, the reactivity of biochar is better than that of anthracite. The gasification of biochar could produce reducing condition of φco/（φco--φco2 ） about 10 %- 20 % between 700-- 800 ℃, which is in accord with the atmosphere and temperature of Fe2 O3 reduction. So it is beneficial to the reduc- tion of iron mineral of pyrite cinder. Compared with anthracite, bioehar could decrease the roasting temperature from 825 to 750 ℃ and roasting time from 20 to 15 min, which shows that a better effect of magnetization could be ob- tained in the condition of lower temperature and shorter time. Using biochar as reductant, iron concentrate extracted from pyrite cinder as about 64% iron grade could be produced, and the recovery is over 90% under the condition of above 90% grinding particle less than 0. 045 mm and magnetic intensity of 0. 124--0. 194 T.展开更多
Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferr...Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferric sulfate solution which was obtained by leaching pyrite cinders with sulfuric acid. Structure and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope and selected area electron diffraction. The results reveal that the reaction temperature has significant effects on the structure, size and shape of the synthesized hematite particles. Typical hexagonal hematite platelets, about 0.4-0.6 μm in diameter and 0.1 μm in thickness, were prepared at 230 ℃ for 0.5 h. Al^3＋, contained in the sulfuric acid leaching solution as an impurity, plays an extremely important role in the formation of hexagonal hematite. In addition, a possible mechanism about the formation of hexagonal hematite platelets was proposed.展开更多
Micaceous iron oxide （MIO） with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia...Micaceous iron oxide （MIO） with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia solution. The optimal experimental conditions for preparing micaceous iron oxide were investigated by orthogonal experiments. Micaceous iron oxide can be successfully prepared when optimal parameters of total iron concentration of 2.0 mol/L, pH value of 8, n（Fe2＋）/n（Fe3＋） of 0.1, mass of seed crystal of 1 g, reaction temperature of 260 ℃ and reaction time of 30 min are applied. X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and selected area electron diffractometry （SAEM） were adopted to characterize the hydrothermal products prepared under optimal conditions. The results indicate that highly crystallized α-Fe2O3 hexagonal flakes, about 1.0-1.5 μm in diameter and 0.1 μm in thickness, are prepared. Furthermore, the quality of micaceous iron oxide prepared can meet the required characteristics of micaceous iron oxide pigments for paints （ISO 10601--2007）.展开更多
Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulf...Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulfate (PFS) solution was produced by adding suitable amounts of FeSO 4·7H 2O and NaClO 3 into acid leaching solution. By concentrating and drying PFS solution, solid PFS with alkali degree of 6.40%22.4% was prepared. Fe 4.67 (SO 4) 6(OH) 2·20H 2O in the solid PFS was discovered by XRD analysis. FT IR spectroscopy shows that the absorption peaks at 3 400 cm -1 and 1 635 cm -1 arise from OH and absorption peaks at 998 cm -1 and 669 cm -1 come from Fe-OH in the solid PFS.展开更多
The solid polyferric sulfate(PFS) was made by oxidation of pyrite cinders with NaClO 3. It was first time discovered by X-rays diffractometry that when the solid PFS was prepared at temperature below 120 ℃ the main p...The solid polyferric sulfate(PFS) was made by oxidation of pyrite cinders with NaClO 3. It was first time discovered by X-rays diffractometry that when the solid PFS was prepared at temperature below 120 ℃ the main phase of the solid PFS is Fe 4.67(SO 4) 6(OH) 2·20H 2O which disappeared when heating was carried out above 130 ℃ for 2 h and complex physical chemical reactions occurred . In thermal spectra two TG mass loss peaks and DTA exothermic peaks at 170～290 ℃ and 27～160 ℃, respectively, were recorded.展开更多
Pyrite cinder is a kind of solid waste of sulfuric acid industry. After mixing pyrite cinders with sulfuric acid, ferric sulfate was obtained by heating, maturing, dissolving and filtrating. Suitable amounts of FeSO 4...Pyrite cinder is a kind of solid waste of sulfuric acid industry. After mixing pyrite cinders with sulfuric acid, ferric sulfate was obtained by heating, maturing, dissolving and filtrating. Suitable amounts of FeSO 4·7H 2O and NaClO 3 were added into ferric sulfate solution and polyferric sulfate(PFS) solution was produced. Solid PFS was made by concentrating and drying PFS solution. Time-dependent complex colorimetric tests were done while ferron agent reacted with Fe 3+ in the solution. The results show that the proportion of transitional low polymeric species and high polymeric species are increased after PFS solution is transferred into solid PFS. It was discovered by jar tests that solid PFS has very good coagulation effects relevant to the increase of transitional lower polymeric species.展开更多
基金Item Sponsored by National Natural Science Foundation of China(51174253,51304245)
文摘The effect of biochar substituted for anthracite as reductant on magnetizing-roasting pyrite cinder was in- vestigated. The key of magnetizing-roasting is the gasification reaction between reductants and CO2. Since biochar could react with CO2 more rapidly at lower temperature, the reactivity of biochar is better than that of anthracite. The gasification of biochar could produce reducing condition of φco/（φco--φco2 ） about 10 %- 20 % between 700-- 800 ℃, which is in accord with the atmosphere and temperature of Fe2 O3 reduction. So it is beneficial to the reduc- tion of iron mineral of pyrite cinder. Compared with anthracite, bioehar could decrease the roasting temperature from 825 to 750 ℃ and roasting time from 20 to 15 min, which shows that a better effect of magnetization could be ob- tained in the condition of lower temperature and shorter time. Using biochar as reductant, iron concentrate extracted from pyrite cinder as about 64% iron grade could be produced, and the recovery is over 90% under the condition of above 90% grinding particle less than 0. 045 mm and magnetic intensity of 0. 124--0. 194 T.
基金Project(2008A090300016) supported by the Key Science and Technology Item of Guangdong Province,ChinaProject(ZKJ2010022) supported by the Precious Apparatus Opening Center Foundation of Central South University,China
文摘Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferric sulfate solution which was obtained by leaching pyrite cinders with sulfuric acid. Structure and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope and selected area electron diffraction. The results reveal that the reaction temperature has significant effects on the structure, size and shape of the synthesized hematite particles. Typical hexagonal hematite platelets, about 0.4-0.6 μm in diameter and 0.1 μm in thickness, were prepared at 230 ℃ for 0.5 h. Al^3＋, contained in the sulfuric acid leaching solution as an impurity, plays an extremely important role in the formation of hexagonal hematite. In addition, a possible mechanism about the formation of hexagonal hematite platelets was proposed.
基金Project(2008A090300016) supported by Major Science & Technology Special Program of Guangdong Province,China
文摘Micaceous iron oxide （MIO） with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia solution. The optimal experimental conditions for preparing micaceous iron oxide were investigated by orthogonal experiments. Micaceous iron oxide can be successfully prepared when optimal parameters of total iron concentration of 2.0 mol/L, pH value of 8, n（Fe2＋）/n（Fe3＋） of 0.1, mass of seed crystal of 1 g, reaction temperature of 260 ℃ and reaction time of 30 min are applied. X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and selected area electron diffractometry （SAEM） were adopted to characterize the hydrothermal products prepared under optimal conditions. The results indicate that highly crystallized α-Fe2O3 hexagonal flakes, about 1.0-1.5 μm in diameter and 0.1 μm in thickness, are prepared. Furthermore, the quality of micaceous iron oxide prepared can meet the required characteristics of micaceous iron oxide pigments for paints （ISO 10601--2007）.
文摘Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulfate (PFS) solution was produced by adding suitable amounts of FeSO 4·7H 2O and NaClO 3 into acid leaching solution. By concentrating and drying PFS solution, solid PFS with alkali degree of 6.40%22.4% was prepared. Fe 4.67 (SO 4) 6(OH) 2·20H 2O in the solid PFS was discovered by XRD analysis. FT IR spectroscopy shows that the absorption peaks at 3 400 cm -1 and 1 635 cm -1 arise from OH and absorption peaks at 998 cm -1 and 669 cm -1 come from Fe-OH in the solid PFS.
文摘The solid polyferric sulfate(PFS) was made by oxidation of pyrite cinders with NaClO 3. It was first time discovered by X-rays diffractometry that when the solid PFS was prepared at temperature below 120 ℃ the main phase of the solid PFS is Fe 4.67(SO 4) 6(OH) 2·20H 2O which disappeared when heating was carried out above 130 ℃ for 2 h and complex physical chemical reactions occurred . In thermal spectra two TG mass loss peaks and DTA exothermic peaks at 170～290 ℃ and 27～160 ℃, respectively, were recorded.
文摘Pyrite cinder is a kind of solid waste of sulfuric acid industry. After mixing pyrite cinders with sulfuric acid, ferric sulfate was obtained by heating, maturing, dissolving and filtrating. Suitable amounts of FeSO 4·7H 2O and NaClO 3 were added into ferric sulfate solution and polyferric sulfate(PFS) solution was produced. Solid PFS was made by concentrating and drying PFS solution. Time-dependent complex colorimetric tests were done while ferron agent reacted with Fe 3+ in the solution. The results show that the proportion of transitional low polymeric species and high polymeric species are increased after PFS solution is transferred into solid PFS. It was discovered by jar tests that solid PFS has very good coagulation effects relevant to the increase of transitional lower polymeric species.
