Limonite 2019-12-13 09:23:24

Introduction Of Limonite

Limonite is one of the main iron minerals. It is a brown natural multi-mineral mixture based on hydrated iron oxide. Although limonite contains less iron than magnetite and hematite, it is also an important iron ore because it is relatively loose and easy to smelt.


Name: Limonite

Composition: Fe2O3-nH2O

Hardness: 1--5.5

Shape: lumpy, earthy, stalactite or grape-like

Color: tan or dark brown

Limonite beneficiation process

Limonite is a poorly selectable iron mineral in iron ore. Its density and magnetic properties are not as good as those of iron minerals such as magnetite, hematite, and specularite, and it is easy to muddy, and the selection index is poor. Because limonite is rich in crystal water, it is difficult to reach 60% of the iron concentrate grade by physical beneficiation, but the grade of iron concentrate is greatly improved due to the large burning loss after roasting. Because limonite is easily sludged during the crushing and grinding process, it is difficult to obtain a high metal recovery rate. From the current production situation at home and abroad, the main use is high-grade limonite as a roasting blending ore; low-grade (TFe <35%) limonite resources have a lower utilization degree, and the beneficiation index is poor. Concentrate grades can generally be increased by 8-10%

Traditional lionite separation methods are mainly washing-gravity separation, strong magnetic separation and magnetic roasting magnetic separation, etc. With the increase in demand and quality requirements for iron ore and the progress of beneficiation technology, the flotation of limonite Elections are beginning to be valued and applied. This year, with the development of new high gradient strong magnetic separators and new high-efficiency reverse flotation agents, there are two major types of combined separation processes, such as strong magnetic separation, reverse flotation, and roasting, and combined beneficiation processes. The single selection process includes reselection, magnetic separation, and flotation processes; the combined selection process includes roasting-weak magnetic separation, flotation-magnetic separation, and reselection-magnetic separation processes.

Single sorting process for limonite

For ore with higher iron content and better selectivity, a simple single separation process is usually adopted, including re-selection, strong magnetic separation and flotation.

Single reselection process

Gravity separation, as the main sorting method for limonite, is used in most cases to handle coarse-grained embedded ore. Reselection process, which is characterized by low cost, simple operation and maintenance, low power consumption, and no chemical reagents are needed in production, but the disadvantages are higher tailings grade, lower iron recovery rate, and unfavorable for comprehensive mineral recycling . Coarse-grained ore is more commonly used for washing ore, jigging and heavy media beneficiation; for fine-grained ore, spiral beneficiation and shaker beneficiation are mostly used.

Because limonite contains a large amount of clay minerals, limonite can be enriched to a certain extent by separating argillaceous materials by ore washing. The ore washing method is simple and economical, and it is a more common method in early limonite dressing plants.

The Lone Star Iron and Steel Concentrator uses a single washing process. After the ore is crushed, it is inspected and sieved, and the product on the sieve is further crushed to 100mm; it is divided into 38 ~ 0mm and 100 ~ 38mm grades and washed separately. The coarse-grained materials are crushed to less than 38mm and washed in three stages. Because the ore is bound by the clay material, the blade ore washing machine is used for ore washing. The overflow of the washing machine and the overflow of the dewatering classifier are the tailings of the washing plant.

The ore composition of the Hunpingping iron ore in Hunan is simple. The metal minerals are mainly limonite, and the gangue minerals are mainly calcite, quartz and clay minerals. The ore grade is 40.27%. After a single water wash and hand washing, the iron can be smelted into the furnace, and the technical conditions for dressing and smelting are good. The main metal minerals of Qibaoshan Iron Ore in Jiangxi are limonite and (water) goethite. The main gangue minerals are quartz, calcite, dolomite and malachite. The ore grade was 46.17%. After washing, the iron concentrate with TFe grade of 51.29% and recovery rate of 56.33% was obtained.

Kazakh limonite company's limonite beneficiation uses a washing-re-dressing process. The ore with a particle size of -400mm enters a toothed roller crusher, and after being crushed to -80mm, it is sent to a double spiral groove washing machine to wash the ore. The washed ore is sent to a vibrating sieve, and the 8mm product is crushed with a flat roll crusher. The -8mm granular product is sent to the spiral groove washing machine with the crushed material for secondary ore washing. After secondary ore washing, the ore is sent to a rake classifier for classification, and the sand returned to the classifier is the concentrate. The classification overflow and secondary washing overflow are dewatered by the hydrocyclone and returned to the classifier, and the hydrocyclone overflow is sent to the chute to separate the tailings. The chute concentrate is jigged together with the overflow from the previous ore washing, and the jigging machine concentrate is returned to the second ore washing as a middle ore.

Jig beneficiation is a classical method for processing coarse-grained iron ore. It is widely used in European and American dressing plants. Most of the limonite beneficiation of the former Soviet Union also used the jig method. The Lisavsky concentrator of the former Soviet Union processes limonite ore, which is produced from sedimentary metamorphic deposits and can be divided into oolitic sand ore and vermiculite oolitic ore. The grade of raw ore is TFe 23.74% ~ 43.56%, and the main veins are quartz and siliceous clay. After the ore is crushed to -2mm, it is deslimed first, and then sorted by a jig. When the selected grade is TFe39.9%, the jigging concentrate grade is TFe48.0%, and the operation recovery rate is about 63%.

Shaker is a kind of flow film beneficiation equipment, which can be generally divided into slime shaker and ore shaker. The feeding requirements of the shaker are very strict, and when reselection is carried out, they are often selected by grade. Yunnan Niushoushan Iron Mine is mainly composed of limonite. The original ore grade is about 29%. It is selected by 1mm classification. The average grade of 1mm grain is 51.51% and the recovery rate is 33.94%. 43.80%, recovery rate is 12.50%; tailings grade is about 20%, recovery rate is 54.06%. A limonite ore in Xinjiang has a TFe grade of 46.50%. The raw ore is ground to -200mm and 80%. The XZY1100 * 500 grooved shaker is used for re-selection, and the stroke, punch times, inclination of the bed surface, water volume and ore supply are adjusted The results of the shaker reselection test show that the concentrate grade is higher, but the tailings grade is higher and the recovery rate is lower.

For different coarse and fine-grained ore, a single re-selection process includes: ore washing, ore washing-gravity separation and shaker beneficiation.

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