First, magnetite ore magnetic separation
Iron ore metal ore magnetic warmed liquid contact school account deposits (rock-sand type), this mineral is the most effective magnetic beneficiation. The sorting process is equipped with one or two sections of dry magnetic separation to select broken or finely divided products as preparation work before sorting.
Dry magnetic separation is mainly for discharging coarse tailings and obtaining further deep selection. The further deep-selected products are finely ground in two or three stages, and then subjected to two-stage or three-stage wet magnetic separation to obtain the final concentrate product. Wet magnetic separation is generally sorted by a permanent magnet cylindrical magnetic separator. The bottom groove of one or two-stage magnetic separator adopts a downstream type; the third or fourth section is mostly semi-reverse type; when the ball mill discharges direct magnetic separation, a countercurrent type or a downstream type is often used.
Second, magnetic quartzite ore magnetic separation
Magnetite quartzite belongs to the ore of sedimentary metamorphic deposits. At present, magnetic separation is widely used at home and abroad to sort this type of ore. This type of ore is called Anshan-type poor magnetite ore in China, and is called iron shale and magnet in foreign countries. quartz rocks, minerals plays an important role in this type of iron ore resources, it is the main target magnetic separation.
The magnetite quartzite beneficiation process is characterized by a stage magnetic separation stage grinding process, which can discharge monomer gangue at a stage and reduce the amount of grinding in the next stage.
The magnetic separation equipment mostly adopts a cylindrical magnetic separator, and the bottom groove is a reverse flow type and a semi-reverse flow type. There are also examples of dewatering using magnetic dewatering tanks at home and abroad.
The following is an introduction to the Dashihe Iron Ore Concentrator of Capital Iron and Steel Company.
The Dashihe Iron Ore Dressing Plant is the main raw material base of the Capital Iron and Steel Company and is located in Qian'an County, Hebei Province. The Dashihe iron ore belongs to the Anshan-type lean magnetite, and the stratigraphic system that constitutes each ore body belongs to the pre-Sinian Mayan well in a strip-like and patch-like structure. Various types of stone are widely developed between the ore bodies and within the ore body. About 15% of the waste rock is mixed in the mining process, the ore is depleted seriously, the geological grade is 30.18%, and the ore grade is only about 25%.
Metal ore minerals are magnetite, followed by a small amount of hematite and martite; gangue minerals quartz, followed by the pyroxene, hornblende, less harmful impurities.
The symbiotic form of magnetite and gangue is simple and easy to dissociate. The magnetite inlay has a coarse and uniform particle size. The crystal having a crystal grain size of 0.062 to 0.5 mm accounts for 60% to 70%, 0.5 to 2 mm accounts for 10% to 20%, and the content of O.062 mm or less accounts for about 10%. Hematite has a finer particle size. The granitic mineral crystal grain size is also relatively coarse, ranging from 0.18 to 0.35 mm. When the ore is ground to -200 mesh and accounts for 75% to 80%, the useful minerals and gangues basically reach the monomer dissociation.
The process uses a stage grinding-weak magnetic separation process. First, the ball mill is pre-selected with a magnetic pulley. Before the grinding, the waste rock with a yield of 8% and a grade of about 9% can be discarded, so that the grade of the milled product can be increased by 2%, and the magnetic iron recovery rate is 99%. The first stage magnetic separation concentrate is subjected to secondary grading and secondary grinding. The secondary magnetic separation concentrate is sieved and returned to the second-stage ball mill after fine screening. The particle size of the three-stage magnetic separation is strictly controlled and improved. The monomer dissociation degree of minerals can increase the final grade of concentrate from 64% to 65% to 67% to 68.5%.
The main technical indicators of the process are: 26.28% of the original ore grade, 68.42% of the concentrate grade, 6.41% of the tailings grade, and the recovery rate of 82.64%.
3. Magnetization roasting and weak magnetic separation of weak magnetic iron minerals
(1) Introduction to magnet roasting
Minerals such as hematite, limonite, siderite, and pyrite are less magnetic and cannot be recovered by weak magnetic separation, but they can be converted into ferromagnetic iron minerals by magnetization roasting (magnetite or Γ-hematite) is then recovered by weak magnetic separation.
Magnetization roasting is a process in which a physicochemical reaction is carried out in a corresponding atmosphere after the ore is heated to a certain temperature. The chemical reaction varies depending on the ore. According to the principle, magnetization roasting can be divided into reduction roasting, neutral roasting and oxidizing roasting.
1. Reduction roasting - suitable for hematite and limonite. Commonly used reducing agents are C, CO and H 2 ratios.
The limonite first discharges the combined water during the heating process, becomes hematite without water, and is then reduced to magnetite.
2. Neutral roasting - suitable for siderite. The siderite is decomposed into magnetite when heated to 300-400 ° C without passing air or a small amount of air.
3. Oxidation roasting - suitable for pyrite. Pyrite is oxidized to pyrrhotite when it is calcined in an oxidizing atmosphere (or a large amount of air) for a short time, and if the oxidation time is long, the pyrrhotite becomes magnetite.
In addition to the above three calcination methods, there are also redox calcination and reduction oxidative calcination, but the most important one is reduction calcination.
The reducing agent for heating the raw material and the reducing process in the calcination can be classified into gas, liquid and solid. The industry's most commonly used is coal gas, heavy oil and coal.
(2) Magnetic separation of calcined products
Anshan-type hematite also plays an important role in China's iron ore resources. The mineral composition in the ore is relatively simple. The main iron minerals are pseudo-hematite, hematite, magnetite, followed by specular iron ore, pyrite, and a small amount of limonite, goethite, siderite and Iron dolomite and so on. Gangue minerals quartz, followed by tremolite, amphiboles, actinolite, sericite, chlorite, calcite, and the like.
Jing Tieshan type iron ore also plays a certain role in iron ore resources. The main iron minerals in the ore are specular iron, limonite and siderite. The main gangue minerals are barite , quartz, jasper and iron dolomite. The ore has two structures, strip and block, and is mainly strip-shaped. The size of the inlaid cloth between the iron minerals is fine, granular or scaly, and there are minerals such as barite and siderite which are not hard, so it is not difficult to break or dissociate.
The block parts of the above two types of ores generally enter the magnetization in the magnetization roaster, the magnetization products are sorted by weak magnetic separation, and the powder ore is sorted by strong magnetic separation or flotation.
4. Strong magnetic separation of weak magnetic iron minerals
Due to the continuous development of the new strong magnetic separator, it has become possible to process weak magnetic ore, especially iron oxide ore, on a large scale by magnetic separation alone. However, in some cases, magnetic separation still needs to be combined with other beneficiation methods to achieve sorting purposes and requirements.
The concentrator often uses two stages of continuous grinding and weak magnetic separation to process 0~10mm fine ore.
The fine ore is ground and graded in one or two stages, and the slag is removed by a cylindrical sieve. The magnetic magnetic separator is used to select the ferromagnetic minerals. The tailings are further subjected to rough selection and two sweeps using a magnetic separator.
V. Magnetic selection of vanadium-containing ferromagnetic ore
The vanadium iron magnetite ore belongs to the ore of the late magma segregation deposit. This type of ore is a subject that is easier to handle in terms of its ore particle size and mineral magnetic properties. At present, it has a certain scale of production in China and abroad, and has a broad development prospect. In addition to containing magnetite ore associated with a plurality of titanium and vanadium, iron, cobalt and nickel of useful elements. Most of the gangue minerals are gabbro.
The main metallic minerals are titanium magnetite ore, iron ore, while a small amount maghemite, exposing, goethite, sulfur cobaltite, sulfur, nickel and cobalt ore, copper ore and yellow ink copper and the like. Gangue minerals titanium augite, plagioclase, followed olivine, amphibole titanium, small amounts of chlorite, serpentine like.
The magnetic ore is often sorted by a closed-circuit grinding and two-stage magnetic separation process, and titanium minerals and vanadium-cobalt-nickel minerals are recovered in combination with other methods.
Aluminum Paste for Building AAC Brick,Aluminum powder for Building AAC Brick,Aluminum Paste for AAC Aerated Concrete Block,luminium Paste Pulver for AAC
Jiangsu Jiali New Material Technology Co., Ltd. , https://www.jlmaterial.com