The feasibility test report of an iron ore in Jiangsu

Guiding experts: Huang Kaiguo, Gong Meiling, Zheng Guangdai, Hu Jiyou, Gu Zhongxiang; project leader: Zhang Shiyin
I. Introduction
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Entrusted by XXXX, Xi’an Tianzhou Mining Science and Technology Development Co., Ltd. conducted an ore washability test on Jiangsu XXXX upper iron ore in November 2008. The iron ore provides a set of economical, reasonable and technically feasible process flow, which provides a scientific basis for the development and utilization of the iron ore.
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During the test, detailed mineralogical research on the iron ore was first carried out, including semi-quantitative analysis of raw ore spectroscopy, chemical multi-element analysis of raw ore, phase analysis of raw ore iron, and raw ore X-ray diffraction analysis. The types and occurrence characteristics of ore minerals as well as the structural characteristics of the ore are ascertained. The particle size distribution and intercalation relationship of the iron mineral were ascertained, and the type, particle size distribution and intercalation relationship of the gangue mineral were ascertained. The researchers have a clearer understanding of the iron ore research, and played a guiding role in the formulation of the iron ore technological process and test conditions.
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The iron ore, as determined by ore technological mineralogy, shows that the phase composition of the ore sample is relatively simple. The ore minerals include magnetite, hematite, limonite and trace pyrite. The structure of the ore mineral is simple, and the ore has undergone slight oxidation and crushing. Therefore, the size distribution and structure of minerals are quite different.
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The ore has a certain degree of oxidation. The limonite and hematite in the ore are both oxidized minerals. The oxidation index of the ore is 22%. It is a moderately oxidized magnetite ore, which accounts for 89% of the metal mineral content. Limonite and hematite account for 11% of metallic minerals. Magnetite is distributed in many forms in the ore; first: it forms granular aggregates, mainly coarse-grained and fine-grained magnetite, the aggregates form a dense mass structure, and magnetite particles can be seen between them Hematite microvein-like metasomatism. Second: sparse granular aggregates. Magnetite is filled with limonite or intersected by limonite veins between particles. Magnetite particles are generally broken, and the particle size is mostly less than 0.074mm. The third type is coarse-grained compact massive magnetite. The size of magnetite is relatively large, generally larger than 0.1mm. Hematite mineralization along the edge of magnetite is very developed, and hematite replaces magnetite. Limonite and hematite mostly exist in the form of colloidal aggregates. Some of the limonite has a ring structure, and the ring is wrapped with a large amount of dust-like components, which proves that the formation of limonite is related to multi-stage oxidation. The structural characteristics of iron ore and hematite determine that magnetite cannot be separated, and it is more difficult to recover.
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The type of iron ore is moderately oxidized magnetite ore, with 59.20% of the total iron in the raw ore, 47.55% of the iron in the magnetic iron, and 80.26% of the total iron in the magnetic iron. Since the iron ore is mainly iron-bearing minerals, magnetite is a strong magnetic iron ore, but the magnetite is partially oxidized and belongs to moderately oxidized magnetite ore. Because part of the magnetite is oxidized, the magnetite of this part of the magnetite becomes weaker. According to the nature of the ore, two technological processes are used in the test; one, the weak magnetic + medium magnetic process, the grinding fineness is -200 The mesh is 70%, the weak magnetic field strength is 1500 Oersted, the medium magnetic field strength is 4000 Oersted, the weak magnetic rough separation, the medium magnetic sweep separation, the total iron grade is 64.81%, and the total iron recovery rate is 94.92%. 2. Medium magnetic field magnetic separation process, grinding fineness-200 mesh 70%, field strength 4000 oersteds-5000 oersteds, one roughing, total iron grade 65.55%, total iron recovery rate 93.98%, for magnetism The recovery of iron is 100%.
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Second, the conclusion
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(1) Summary of technological mineralogy research
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The composition of the upper iron ore of Jiangsu XXXX is relatively simple. The ore minerals include magnetite, hematite, limonite and trace pyrite. Gangue minerals mainly include carbonate, quartz, muscovite, etc. Magnetite accounts for 89% of the metal mineral content, limonite and hematite account for 11% of the total metal minerals, and magnetite is mainly equiaxed granular. All are enriched by metamorphism and recrystallization. Most of the magnetite has a particle size of less than 0.1mm, mostly in particulate form. Limonite and hematite mainly exist in the form of colloidal aggregates, and the formation of some limonite is related to multi-stage oxidation. The structural characteristics of limonite ore determine the difficulty of recovery. The iron ore belongs to moderately oxidized magnetite.
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(2) Test process flow and test indicators
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The iron ore belongs to moderately oxidized magnetite, which means that some of the magnetite is oxidized, and the magnetite becomes weaker. Therefore, two processes are used according to the ore property test; the first process is weak magnetic + Medium magnetic field process, weak magnetic roughing, medium magnetic scanning, the average grade of all iron is 64.81%, and the recovery rate of all iron is 94.92%. The second process flow is: the medium magnetic field process, the field strength of the medium magnetic field is 4000-5000 Oersted, the test index is 65.55% of the total iron grade, and the total iron recovery rate is about 94%.
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(3) Chemical analysis of iron ore concentrate and tailings
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The iron concentrate has passed chemical multi-element analysis, and all impurities do not exceed the standard, and the iron concentrate meets the national standard first-grade product requirements. In the final tailings, after chemical multi-element analysis, there are no more recycled minerals in the tailings.
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(4) There are problems in the settlement test of iron concentrates and tailings
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Since the iron concentrate contains a small amount of hematite and has a fine particle size, there is a small amount of suspended matter that affects the observation in the iron concentrate sedimentation speed test. The tailings contain mud and fine-grained red limonite, which also affects the observation during the tailings settlement test. It is recommended to add a little flocculation on site to aid settlement.
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(5) Recommended process flow
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Two technological processes were used in this test: one, the weak magnetic rough separation and the medium magnetic sweep separation process; the second, the medium magnetic field magnetic separation process. The test indicators of the two processes are similar, and the first one is more flexible. The second type of process is simple, and it is recommended that the mine and the designer jointly negotiate and select the process.
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(6) Economic benefits
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Through detailed ore selectivity test research, a set of economically reasonable and technically feasible process flow is provided for the iron ore, and the economic benefits are preliminary estimated. The iron concentrator with a daily processing capacity of 500 tons will be built, with an annual working day of 300 days, and an annual profit and tax of 78,655,500 yuan. Yuan, the economic and social benefits are very considerable, the mine has development and utilization value, this test can be used as a basis for the design of the concentrator.
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(7) Grade of raw ore
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The total iron grade of the test sample collected this time is 59.20%, but from the geological report, the average grade of the mine’s total iron is only 42.5%, which is depleted by 10% at the time of sampling. The sampled product has a large deviation from the average grade of the mine. To fully comply with the actual production, it is recommended to re-take samples that meet the average grade of the mine for process verification tests.
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(8) Dry election and discard the tail
Regarding “dry election and throwing”, it can be considered, but the effect of throwing tail and the location of throwing tail need to be verified and agreed. Because this operation is placed before the ball mill, in the rainy season, the water content in the ore is large. If the ore has a high level of fineness, it will produce “magnetic clusters”, which will affect the tail-throwing effect.