Several application fields and actual cases of iron tailings

The comprehensive utilization of tailings resources is generally divided into two aspects. First of all, the most economic value of the tailings which contained a variety of valuable metals and minerals, which must be considered when tailings utilization. Second, consider the overall utilization of tailings. The following will be explained and illustrated separately.

I. Re-election of iron tailings and comprehensive recovery of valuable elements

The first thing to do in the recovery of useful components from tailings is to carefully study the content of the useful components in the tailings (qualitative, quantitative detection) and the state of existence.

(1) Re-election of tailings by magnetic separator

Iron ore in Nanshan Washan iron processing plant tailings annual amount of 3.5 million t, Ma On Shan Institute of Mining designed with a diameter of 500 mm, a length of 4 mm disc separator sorting, obtained in 5% yield ~6%, the iron concentrate 29% ~ 31% of the coarse concentrate, after re-grinding and re-election can obtain a qualified concentrate of 2% yield, iron grade 60% ~ 63%. The project has been in operation for many years, and the annual recovery of iron ore concentrate is nearly 40,000 tons. The use of shaker to recover sulfur concentrates can reach more than 30% of grades, and the annual recovery of sulfur concentrates is more than 50,000 tons.

(2) Recovery of iron from tailings by roasting and re-election

In the shaft furnace roasting test of Guangxi Wuqiu Iron Mine, the iron content of the magnetic separation tailings is as high as 27%. The tailings are further reduced and calcined, and then the iron concentrate is directly magnetically selected to reduce the iron content of the tailings. About 10%, and then re-selection of iron from the re -election equipment such as shaker and centrifuge, the test obtained 13.84% of the iron recovery rate of re-concentration concentrate. In this way, after combining with the magnetically selected iron ore concentrate, a comprehensive iron concentrate containing 55.06% of iron and 91.12% of iron recovery can be obtained.

Test results from various types of ore samples (mixed ore samples, powder ore samples, lean ore samples and rich ore samples) prove that the magnetic properties of roasting magnetic ore have good adaptability to iron ore, and each ore sample under certain processing conditions Correspondingly, iron concentrates containing 55% to 57% of iron and an average recovery of iron of 90% or more can be obtained.

Second, the overall utilization of iron tailings and various possible uses

The recovery of valuable components from tailings, despite important economic benefits and certain social and environmental benefits, but the amount of tailings can not be reduced, still can not fundamentally solve the tailings pressure on the land, damage And issues affecting the environment. To this end, it is necessary to strengthen the development of the overall utilization of tailings. Moreover, as a composite mineral raw material for building materials, ceramics and glass industry, tailings has achieved initial results in application and has broad prospects. The following are summarized separately:

(1) Iron tailings for building materials

The waste rock thrown out during the beneficiation process and the tailings produced during the magnetic separation process are directly used as building materials. There are some mines such as Magang Gushan Iron Mine, Shanghai Meishan Iron Mine, Jiangsu Jishan Iron Mine, and Shougang Dashihe Iron Mine. These mines have carried out this work in combination with their own beneficiation process and local resources, and have achieved certain economic benefits. For example, the Mashan Iron and Steel Co., Ltd. exports 4 to 12 mm long tailings for concrete for civil and industrial construction. The aggregate of concrete supported by the roadway uses <0.5mm fine tailings sand instead of yellow sand. The sales income in the above two years is more than 1.15 million yuan.

1. For the production of cement

The Taochong Iron Mine has established a cement plant. According to the planned annual production of cement, it needs to purchase 6000t of iron powder, which requires about 360,000 yuan. It is now replaced by tailings, which can save this expense. And the tailings consumption for making cement is about 280,000 tons. The mine produces 200,000 tons of tailings per year. The tailings consumption for making cement accounts for 1/7 of the total annual output of tailings, which also reduces The tailings' transportation volume and stockpiling amount save the company's expenses.

2, used as glass raw materials

Some high silicon tailings, such as gold tailings tailings, tungsten mine tailings, mine tailings, and some kaolin potassium-rich feldspar, such as niobium, tantalum Ore (such tailings containing both silica and potassium It is a well-known fact that feldspar and the like can be used as raw materials for glass. However, if the iron content in the tailings is high, it cannot be used as a raw material for flat glass, but only as a raw material for colored bottle glass.

3, used to manufacture glass-ceramic materials

One of the high-grade architectural decorative materials of glass-ceramic decorative materials, it has the characteristics of high strength, wear resistance, high gloss, no color difference, and can be arbitrarily colored. Several experts in our hospital have been the first to carry out research on the use of tailings to manufacture glass-ceramics, which have been successful. In order to adapt to the complex and varied characteristics of tailings, our experts have also compiled a computerized batching system for glass-ceramics, which has been verified by a large number of tests and has passed the expert's appraisal.

Shijiazhuang City has a microcrystalline glass factory, and the benefits have been very good.

The tailings suitable for the manufacture of glass-ceramics are high-silicon low-iron tailings, preferably containing a certain amount of alkali metals, such as some kaolin mines, gold mines, tailings of tungsten mines, and the like. Current use of glass-ceramic material fired regular multi-single crystalline phase, NTUT in the development of a vanadium and titanium ore tailings for the manufacture of crystallized glass, since the tailings component complex crystal phase appeared bis (silica fume The glass-ceramic and diopside glass-ceramics have a good effect, indicating that the glass-ceramics can also be made when the raw material composition is complicated. It is worth noting that glass-ceramics can also be used as insulating materials due to their high insulation.

(ii) For sewage treatment

1. Used as a material for direct degradation of heavy metals during sewage treatment

The principle of tailings purification of sewage is: adding tailings mud into urban sewage, the slime can adsorb heavy metal ions on the surface of the tailings, forming sediments separated from the water, and it is more sufficient than the general hydroxide adsorption separation. Studies have shown that if the adsorption is a pure surface combination, then a few pounds of metal can be adsorbed per ton of tailings; if it can combine chemical reactions, such as, for example, pyrrhotite chemically acts on mercury ions, then each ton of tailings can be absorbed. Hundreds of pounds of metal. According to China Internet October 13, 2004 reported: "natural pyrrhotite, previous studies have shown that it has an excellent ability to deal with hexavalent chromium waste water." This is another example, and It shows that pyrrhotite can not only be used to treat mercury-containing wastewater, but also to treat chromium-containing wastewater.

2. Used as a filter material for physical treatment of sewage

Physical treatment of sewage is often used for primary treatment to remove suspended solids or emulsifiers from sewage. There are many kinds of physical methods, among which the filter materials commonly used in the filtration method are quartz sand, garnet particles, magnetite particles, dolomite grains, granite grains, etc., and titanium ore is also used abroad. These materials are common in tailings sand. However, it can be used as such a filter material to have a certain particle size requirement; for example, the grain size requirement for quartz sand is 0.1 to 1.2 mm, and the requirement for garnet sand is 0.2 to 0.5 mm.

3. As an alkaline filter for chemical treatment of acidic wastewater

Chemical treatment is often used in the treatment of industrial wastewater. There are several methods, among which there are three kinds of filter media for the filtration neutralization method (when the acid concentration is not too large): limestone , marble and dolomite. These three kinds of rocks are common in mine waste rock, but because of their small amount and small block size, they can neither be used as building materials nor can be used as burnt lime or as a smelting solvent, and if there is a factory nearby Acidic wastewater treatment is required, and it is selected for use as a filter material.

4. Used as filter material for aerated biological filter (BAF)

At present, the maximum amount of tailings or waste rock used for sewage treatment may be the filter material of advanced aerated biological filter sewage treatment. Including professional name is "Arlita" of media, our hospital experts, can use high clay mineral content in tailings or waste rock shale (including coal gangue), and add a small amount of materials to manufacture. In line with the requirements of this raw material, it is necessary to contain more clay minerals such as illite or Montmorillonite. These minerals are characterized by melting and swelling substantially synchronously when calcined at a high temperature.

(3) Iron tailings for soil amendments and trace element fertilizers

1. Used as a soil conditioner

Some, such as tailings or a magnesium-rich calcium carbonate, may be used as a raw material mineral acid soil improvement. For example, Japan hopes that the tailings of the Dafeng Concentrator will be a salt-based tailings. The rice planting test proves that the tailings are suitable for neutralizing old and acidic soils and helping to improve soil quality. Some tailings contain gypsum and can be used as a mineral raw material for improving alkaline or weak saline soils. The tailings containing pyrite can be used to acidify soils with high carbonates, especially those containing sodium carbonate. When using tailings as a soil amendment, check whether the harmful components are exceeded.

2, used to produce micro-fertilizer

Trace chemical fertilizers are considered to be "vitamins" for plant growth. It has been found that there are at least a dozen micro-fertilizers, such as: Zn, Mn, B, Mo, V, Co, Li, Ti and some rare earth elements. The micro-fertilizer has a significant effect on increasing yield, and the yield increase is 5% to 30% for crop and soil characteristics. Most micro-fertilizers are chemical products, and the amount of fertilizer applied is in grams per acre.

The K ₂ O content in a selected iron tailings mine in Hubei is 3%. At present, the mine has successfully used the tailings to prepare potassium and calcium fertilizers. The Heilongjiang Jixi Concentrator uses tailings to develop magnesium and potassium fertilizers, and the Henan No. 1 Concentrator uses tails. ore as the main raw materials to produce calcium and magnesium phosphate fertilizer.

Magnetic fertilizer is one of the new fertilizers recognized at home and abroad this year. China Maanshan Mine Research Institute has studied magnetized iron ore tailings as a magnetic fertilizer and achieved results as early as the 1980s. China's current mining of iron ore, the ore produced by magnetite ore is the majority, so this use is worthy of attention.

Although the above lists some possible areas of use of tailings, in fact, it is not only these applicable fields, but only the role of throwing bricks and jade is proposed here. Inappropriate, please correct me.

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