1. beneficiation test of iron ore
the phase analysis of iron is very telling. Take lean magnetite as an example, the occupancy rate of magnetic iron is actually the recovery rate of low-intensity magnetic separation. After magnetic iron is separated, it is dried, weighed and then its Fe content is determined, which is the best iron grade index of concentrate. The results of phase analysis and iron recovery by low-intensity magnetic separation of some poor magnetite deposits are listed in Table 6.2.
table 6.2 phase analysis and mineral processing recovery rate of iron in some poor magnetite deposits
from the magnetic iron occupancy rate in table 6.2, that is, the possible iron recovery rate of low-intensity magnetic separation is very close to the actual recovery rate of low-intensity magnetic separation.
2. beneficiation test of removing harmful components from iron ore
beneficiation test of reducing harmful components in iron ore. Using phase analysis technology to find out the occurrence state of harmful components in iron ore can often get twice the result with half the effort.
Guangdong Lishan iron mine has an average Fe grade of 55%, which is already a blast furnace rich grade. But the ore contains .13% Sn, .13% Pb, .4% Zn and .19% Cu. However, the requirements of these elements for blast furnace rich ore are that Sn is not more than .8%, Pb is not more than .1%, Zn is not more than .2%, and Cu is not more than .2%. Sn, Pb and Zn all exceed the allowable content.
The occurrence states of Fe, Sn, Pb, Zn and Cu were found by phase analysis method, which can be summarized as follows:
Iron: The original ore contains 54.95% Fe, but it is mainly magnetite, but it has been seriously oxidized. According to mineral quantity, magnetite (Fe3O4) accounts for 6.7%, pseudohematite (Fe2O3) accounts for 24.1%, and limonite.
tin: the original ore contains .123% Sn, which exists in three States: ① cassiterite with monomer dissociation accounts for 14% of total Sn; ② 49% of the total Sn exists as microcrystal inclusions; ③ Colloidal tin accounts for 37% of total Sn. Based on iron minerals, the single mineral of magnetite contains .6% Sn, and Sn mainly exists as microcrystal inclusions. The single mineral of pseudohematite contains .66% Sn, and Sn also mainly exists as microcrystal inclusions. The Sn content of limonite is .15%. Among them, Sn and colloidal tin in the form of microcrystal inclusions account for about half each.
lead: the original ore contains .13% Pb, which exists in three states: ① galena and galena, which are independent minerals, account for .5% and .2% respectively; ② The content of Pb in manganese soil minerals is .37%, and the average Pb/Mn ratio is .2; ③ Limonite contains .75% Pb, which mainly exists in colloidal mineral state, and the single mineral of limonite contains .13% Pb.
zinc: the original ore contains .4% Zn, which exists in three states: ① smithsonite mainly exists as an independent mineral, accounting for .68% in terms of Zn; ② Manganese soil minerals contain .1% Zn, with an average Zn/Mn ratio of .5%; ③ Limonite contains .24% Zn, which mainly exists in colloidal mineral state, and the single mineral of limonite contains .417% Zn.
copper: the original ore contains .19% Cu, which exists in three states: ① chalcopyrite and malachite exist as independent minerals, accounting for .7% and .7% of Cu respectively; ② Manganese soil minerals contain .19% Cu, with an average Cu/Mn ratio of .1%; ③ The limonite contains .167% Cu, and the limonite single mineral contains .29% Cu.
The analysis results of the occurrence state of five elements show that only magnetite and pseudohematite are selected by low-intensity magnetic separation by mechanical beneficiation, and the iron concentrate with the content of harmful components meeting the requirements can be obtained. The practice of mineral processing test proves this point. The obtained concentrate contains Fe 6.8%, Sn .65%, Pb .8%, Zn .17% and Cu .8%. The recovery rate is 56.47%. The tailings of low intensity magnetic separation, namely limonite, can generally be used for ore blending. If harmful components are to be reduced to qualified products, only chemical beneficiation methods, such as chlorination roasting, can be used. But whether the economic indicators are reasonable must be considered.
3. beneficiation test of chromite
phase analysis of chromite is to determine Cr2O3 and Fe after obtaining the chromite spinel minerals by selective retention, which is the simplest method to predict the Cr2O3 grade, the ratio of chromium to iron (w(Cr2O3)/w(TFe)) and the recovery rate of beneficiation concentrate. According to the phase analysis of chromium in the first chapter, the spinel phase of chromium is dried and weighed. The contents of Cr2O3 and Fe were determined respectively. The content of Cr2O3 is the highest Cr2O3 grade index of concentrate. W(Cr2O3)/w(TFe) This is the best Cr-Fe ratio index of the product. The ratio of Cr2O3 to total Cr2O3 in chrome spinel phase is the best recovery prediction index of mineral processing. If the disseminated particle size of chrome spinel is coarse and the association with gangue minerals is not serious, the predicted index of phase analysis can be very close to that of mineral processing products. If the chromite spinel exists as disseminated, the actual index is much lower than predicted. The comparison between the phase analysis and prediction indexes of some chromite ores and the actual achievement indexes of beneficiation concentrates is shown in Table 6.3.
4. Mineral processing test of manganese ore
Mineral processing test of a high phosphorus manganese ore in Shaanxi Province, after the phase distribution of manganese and phosphorus was found out by phase analysis, the mineral processing tester quickly determined the technological process and obtained the qualified manganese concentrate.
the high phosphorus manganese ore contains Mn 1.92% and P 1.1%. Mineral processing indexes require that the concentrate meet the national standards, that is, Mn is not less than 3%, P is not more than .2%, or P/Mn is not more than .6.
table 6.3 phase analysis and prediction indexes of some chromite deposits and actual comparison of mineral processing
before arranging the phase analysis, the experimenters have carried out high intensity magnetic separation and flotation tests on the raw ore samples. The manganese concentrate with high intensity magnetic separation contains 18.41% Mn, .31% P and .168 P/Mn, and the recovery rate is 71.16%. The flotation manganese concentrate contains Mn 17.25%, P .39%, P/Mn .225, and the recovery rate is 57.2%, which is far from the required standard.
phase analysis shows that manganese mainly exists in three phases, namely, pyrolusite state Mn is .42%, travertine state Mn is 4.%, and manganese dolomite state Mn is 6.5%. The phase of phosphorus shows that almost all phosphorus exists in apatite and collophanite, and no manganese-containing phosphate minerals is found.
according to the data of phase analysis, it is almost impossible for several minerals containing manganese to obtain products that meet the national standard by a single mechanical beneficiation method. According to the physical and chemical properties of manganese-bearing minerals and phosphate-bearing minerals, the experimenter drew up a process flow of high intensity magnetic separation-roasting-acid leaching. Roasting can decompose manganese carbonate into Mn3O4 and MnO2, burn off CO2 and improve the grade of Mn concentrate. Acid leaching, treating soluble apatite and collophanite with dilute H2SO4 to reduce the P content in the concentrate. The manganese concentrate obtained by this process contains 32.94% Mn, .192% P and .58 P/Mn, and the recovery rate is 63.9%.
Of course, the industrial utilization value of such manganese ore is very low. However, as a mineral processing experimental study, the mineral processing flowsheet designed according to the phase analysis results of manganese and phosphorus is reasonable.