Beneficiation process and technology of various iron ores Iron sore sorting technology

Mineral processing technology and mineral processing equipment are developed at the same time. The technical level of equipment not only reflects the mineral processing technology, but also directly affects the production process, effect, efficiency and economic benefits of industrial ore dressing.

Industrial ore dressing process mainly includes crushing, screening, grinding (ball mill), classification (classifier), separation (gravity separation, flotation, magnetic separation, photoelectric separation), mineral dehydration (concentration, filtration, drying, etc.). The final purpose of beneficiation is mainly to separate minerals from gangue, so as to achieve monomer separation and make final preparation for separation operation.

Beneficiation equipment mainly includes crusher, feeder, ball mill, classifier, vibrator, shaker, magnetic separator, mixing bucket, flotation machine, artificial intelligence separator and other equipment.

There are many kinds of iron ores, which can be mainly divided into strong magnetic iron ores and weak magnetic iron ores, among which strong magnetic iron ores include magnetite, titanomagnetite and pyrrhotite; Weak magnetic iron ores include hematite, pseudohematite, limonite, siderite and ilmenite. According to the characteristics of different iron ores, there will be different beneficiation processes.

The following are mainly the beneficiation processes and emerging beneficiation technologies applied to different iron ores

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1. Beneficiation of strong magnetic ore

Strong magnetite is mainly divided into two types of single type and polymetallic type magnetite.

① Single type magnetite beneficiation

The mineral substance of single type magnetite ore is mainly magnetite. Due to its simple composition, weak magnetic separation is usually used for beneficiation.

According to the limit of magnetite grinding particle size of 0.2mm, one-stage grinding magnetic separation is adopted when the size is larger than 0.2mm; If it is less than 0.2mm, two-stage grinding magnetic separation is adopted. If the qualified tailings can be separated in the coarse grinding stage, the separation grinding magnetic separation is adopted. For some water shortage areas, dry grinding and dry magnetic separation are adopted.

At the same time, in order to obtain high grade iron ore concentrate, concentrate can be enriched by flotation, shock fine screen, etc.

② Beneficiation of polymetallic magnetite

The processing of polymetallic magnetite is mainly composed of silicate or carbonate minerals, and associated with cobalt pyrite, chalcopyrite and apatite, the weak magnetic separation reverse flotation process can be used, that is, the weak magnetic separation process is used to recover iron, and then the flotation process is used to recover sulfide or apatite.

According to the different reagent systems, especially the types of collectors, the weak magnetic separation reverse flotation process can be divided into weak magnetic separation cation reverse flotation process and weak magnetic separation anion reverse flotation process.

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2. Beneficiation of weak magnetic ore

Weak magnetite is also divided into two types of single type and polymetallic weak magnetite.

① Beneficiation of single weak magnetic iron ore

Single weakly magnetic iron ores mainly include hematite, siderite, limonite and hematite (specularite) - siderite, etc. Because this kind of mineral involves many kinds and has a wide range of embedded particle sizes, the beneficiation method is also complex, and gravity separation, flotation, high intensity magnetic separation or their combined processes are often used. At the same time, photoelectric separation can also be used to enrich the iron ore grade before the existing beneficiation process.

The flotation process is used to separate fine and fine weakly magnetic iron ores, mainly including positive flotation and reverse flotation. Among them, the positive flotation process is applicable to quartz hematite ore without easy floatation gangue, while the reverse flotation process is applicable to gangue easy floatation ore.

Gravity separation and high intensity magnetic separation are mainly used for 2-20mm and medium weak magnetite, and heavy medium or jigging beneficiation of ore larger than 20mm, or artificial intelligence machine can be used for beneficiation.

The photoelectric separation process is applicable to ores with particle size of 0.5-10cm. Through artificial intelligent separation equipment, waste gangue is pre discarded, iron ore is enriched, grinding and iron ore flotation are reduced, and the overall economic benefits of the mine are improved.

② Beneficiation of polymetallic weakly magnetic iron ores

They are mainly hydrothermal and sedimentary hematite ore or siderite ore containing phosphorus or sulfide. Such ores are generally recovered from iron minerals by photoelectric separation, gravity separation, flotation, strong magnetic separation or their combined processes, and phosphorus or sulfide by flotation.

Hydrothermal apatite bearing hematite ore and copper bearing pyrite can be flotation.

Sedimentary phosphorus containing oolitic hematite ore can be separated from iron by flotation, but it is often difficult to enrich phosphorus concentrate, and the iron recovery rate is greatly reduced. It can be considered to smelt high phosphorus pig iron and recover steel slag phosphate fertilizer after removing large grain gangue by artificial intelligence sorting equipment.

The above are common ore dressing methods. The above methods can be used for reference when processing iron ore beneficiation. However, in actual beneficiation, it is necessary to go through beneficiation tests to determine the ore composition and ore properties, and then, according to the analysis results, actual conditions and investment conditions, customize a reasonable process flow that meets its own mine conditions.

At the present stage, mine beneficiation mainly applies gravity separation, magnetic separation, flotation or combined process. However, in the development of beneficiation processes at home and abroad, the fourth beneficiation process - photoelectric separation has also undergone nearly 20 years of development, from the initial color separation era to artificial intelligence separation. Among them, the representative brand "Mingde Optoelectronics" has been specialized in ore beneficiation since its inception, The representative products of photoelectric separation include ore color separator, mineral sand separator, artificial intelligent separator and X-ray intelligent separator. In the field of iron ore separation, in order to solve the problem of ore dressing difficulties, improve the comprehensive utilization rate of mine resources, drive the overall economic benefits and other advantages, it has accumulated mature experience, and has been applied to various metal and non-metallic ore dressing fields.