The mining, ore crushing and grinding process and Sorting Technology

After 40 years of China's capital, has been completed and iron mines 204. Which: focus Mine 44, the state-owned and locally-administrated Mine 160, a total iron ore mining capacity of 197.19 million t.
Iron Mine pioneering style of open pit mining and underground mining (EOC Cave, the inclined shaft, the shaft) two categories. Our country in the 1949 to 1957 period, more than 80 percent of the mine for underground mining, open pit mining, and less than 20 percent. Subsequent , as a number of open-pit mine have been completed and put into production, the proportion of underground mining sharp decline, to the early 1990s, the proportion of Surface Mining rose by 80 percent, while the proportion of underground mining dropped to 20 percent.

(A) The open pit mining

In 1996 the open pit mining of iron ore ore capacity of 185.38 million tons, the country's total iron ore ore production of 73.5 percent. Focus Open Pit Mine 27, the Communist iron ore ore of 91.06 million tons, accounting for emphasis mine ore production 106370000 t 85.6

Opencast perforation, and shovels equipment, and transport technology is continuously updated. Currently, the nation's key mine perforation has formed cone submersible drilling and drilling holes and using the structure, completely eliminated the impact of drilling .1996, the cone drill in the Taiwan comprehensive efficiency for the 23,787 m, the maximum 31,611 m (Waterworks iron ore); Taiwan submersible drilling holes in the Composite efficiency 14066 m, the maximum 25,279 m (Lanjian Iron Mine). Backhoe installed equipment in a large, modern direction of .1996, the focus of the largest open-pit mine use 4 ~ 4.6 m3 power shovel, and Taiwan, the average consolidated efficiency 1333000 t, the largest capacity of 16 m3 electric shovel, and Taiwan, the average efficiency of 3.475 million t, the highest 4821000 t (Qida Iron Mine). main mode of transport for the car and rail 108 t efficiency of motor vehicles in Taiwan, an average of 359,000 t; 154t car for 895,000 t to a maximum 1.23 million t (Qida Iron Mine); use up the 42 t cars, Taiwan, the average efficiency for 276,000 t to a maximum 443,000 t ( Bayan Obo iron ore) .1965 years later, some key mines used railway transport motor vehicles, in 1996, focusing on open pit mining of the mine motor vehicles in Taiwan, the average efficiency: 80 t motor vehicles for the 791,800 t, 100t motor vehicles to 549,900 t , 150 t motor vehicles for 882,600 t.

Open pit mining of mining technology, promoting long-term use throughout the wide level to help ease the operations stripping process has now begun to steep wall mining, horizontal push the new technology .80 1950s, many large-scale open-pit mine open by the slope into the concave mining, as operating conditions deteriorate and transport problems, thereby constraining production capacity increase .1994 started to implement the "Deep integrated open pit mining technology research," the "Eighth Five" key project has now achieved initial results.
The blasting equipment and the development of technology has also gradually adopted the rock explosives, ANFO explosives, ammonium nitrate explosives, explosives and so on emulsified oil, applied in the production of large-area multi-millisecond blasting technology.

(B) underground mining

: Produced an average ore grade of 36.9% at a recovery rate of 76.2%, the dilution ratio 19.8%, the rate of decline 6.98 m.
Currently, the mining underground mining method is mainly Pillarless mining law, about 72 percent, followed by the shallow-hole mining method, accounting for nine percent, and the wall of room and pillar mining method accounted for 8 percent, and air field method accounted for 7% , a pillar sublevel caving mining method accounted for 3%, filling method of one percent. mines underground mining roadway support from the 50's wooden support to the development of wood supporting now, and sprayed concrete support three anchor Support Supporting methods coexist situation. drilling to shipment also gradually develop in the direction of mechanization, it is now commonly used by rock-drilling platform vehicle drilling, shipping machine shovel equipment, motor vehicle transportation. due to mining methods, technology and equipment, and supporting the methods continuous improvement, underground mines all-personnel labor productivity has been greatly improved, the founding of New China, the 1949, the nation's key underground mines all-personnel labor productivity only 19.9 t / (a), the 1995 has reached 561 t / ( people a), increased by nearly 30 times.

Third, beneficiation and processing technology

China's iron ore and more because of the poor (of the total reserves of 97.5%) and with (a total of) Health and other components of integrated multi-mine (of the total reserves of 1 / 3), in the vast majority of the need for smelting before handling Beneficiation .
1996 National iron ore 214970000 t selected, the total domestic iron ore ore 252.28 million t of 85.2 percent. Selected iron ore production iron concentrate powder 85857000 t, which focus concentrator processing ore 109.61 million t, iron concentrate powder production 41580000 t, of the nation's output of iron ore powder of 48.4 percent.

(1) ore crusher

My Concentrator generally use the rough broken, and broken in three small broken broken iron ore crushing process. Rough break more 1.2 m or 1.5 m cycles breakers, breaking in the use of 2.1 m or 2.2 m standard cone crusher, small broken by 2.1 m or 2.2 m short head cone crusher. crude broke through the ore, the block of not more than 1 m, then passing through, small broken ore screening into the particle size less than 12 mm grinding final product delivery trough.

(B) grinding process

China's iron ore grinding process, the majority of using two grinding process, a section of small and medium Concentrator use of grinding processes. Fine sieve to the use of new technology mill, concentrator has been in recent years, two to three grinding grinding. grinding equipment used in general relatively small, the greatest ball mill 3.6 m × 6m, the largest rod mill 3.2 m × 4.5m, the biggest since the mill 5.5 m × 1.8m, gravel grinder 2.7 m × 3.6m.
After the grinding classification is basically the use of spiral classifier. In order to improve efficiency, water Concentrator part of the Cyclone replace secondary spiral classifier.

(C) sorting technology

1. Magnetite Beneficiation

These are mainly used for sorting the low-grade "Anshan" magnetite. Due to strong magnetic ore, Toshima good election, the domestic stage magnetic separation plants have adopted multi-stage grinding and grinding processes, for coarse-grained magnetite using embedded fabrics the former (a section grinding), Fine, Fine-grained magnetite containing fabrics used the latter (2, or 3 of grinding) (Chart 3.2.23). serialization of our own developed by the permanent magnet, the Magnetic Separator achieving a permanent magnet of .70 age, as magnetite concentrator in the country to promote the fine sieve regrinding new technologies to concentrate grade from 62 percent to 66 percent, the Ministry of Industry has proposed metallurgical concentrate grade reached 65% requirements.

Figure 3.2.23 Gongchangling iron magnetic separation process and Fine Screen
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2. Weakly magnetic iron ore beneficiation

These are mainly used for sorting hematite, limonite, pyrite mirrors, siderite, false or mixed hematite ore, which is the so-called "red ore." Such low-grade ore, containing fine granularity cloth, mineral composition complex, sorting difficulties .80 late 1980s, the beneficiation technology for roasting magnetic separation, wet strong magnetic separation, flotation and weak magnetic re-election, and other process, equipment and new varieties of pharmaceutical research continue to improve, so that Concentrate grade, metal recoveries continues to increase. Qida such as Anshan Iron Mountain Concentrator using weak magnetic - strongly magnetic - the new flotation process (Figure 3.2.24), was encouraging achievements.
Figure 3.2.24 Qida Hill election process plant
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3. Polymetallic total (with) The ore beneficiation

Such ore complex, diverse and therefore the methodology, equipment and processes are different, such as the use of anti-Bayan Obo pyrite flotation - Multi - gradient magnetic separation, flotation flocculation, weak magnetic - reverse flotation - Strong magnetic separation, the weak magnetic - are flotation, magnetic separation, and so on different roasting process to improve the recovery rate of iron and comprehensive recovery of rare earth oxides. Panzhihua Iron through magnetic separation was TFe53 percent vanadium iron ore concentrate, magnetic After the election of weak magnetic tailings sweep through the election - Strong magnetic separation - re-election - Flotation - dry electrostatic separation, access to concentrate titanium and cobalt concentrate sulfur recovery of titanium and cobalt. Daye by weak magnetic iron ore - strongly magnetic and flotation, comprehensive recycling iron, copper and cobalt, sulfur and other elements.
Table 3.2.11 listed in 1996 China's iron ore concentrator focus on different types of ore beneficiation technology economic indicators.

Concentrator Table 3.2.11 focus on technical and economic indicators of ore types
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(D) pellet sintering technology

    My sintering technology is rich artificial means .1996, the main production of man-made rich 160956000 t, of which the key enterprises 94.859 million tons, accounting for 58.9 percent of local state-owned enterprises 61.337 million tons, accounting for 38.1 percent.
Fine China in the technical concentrate sintering has reached a considerable level. Angang Back in the early 1950s in the sintering machine on the successful acid sinter production methods to produce alkaline sinter, in the world's first use hydrated lime or quicklime for a small flux concentrate sintering solve the problem.

        The pellet sintering equipment level has been upgraded, the total sintering machine 419 units with a total area of 15,522 m2, of which: 130 m2 level and above sintering machine 22 units for a total area of 4,107 m2; 24 ~ 129m2 of sintering machine 197 units for a total area of 9387 m2; less than 24 m2 of sintering machine 3200, the total area 2028 m2.1994, February 24 in Ma On Shan steel factory production of 300 m2 sintering machine, in addition to Baosteel, China's own design, manufacture and construction of the largest modernization sintering machine.

The 1995 sintering the main technical and economic indicators: the utilization factor 1.36 t / (m2 h), sinter grade 53.00%, the sintering machine calendar operating rate 80.94 percent, sinter pass rate for the 84.92%, labor productivity of workers for 2170 t / (h).

4, the Environmental Protection

China's iron and steel industry is a pillar industry, and many heavy industrial bases or cities, such as Anshan (AISC), Panzhihua (Pangang), Ma On Shan (Magang), and so on, are all around the iron and steel industry to develop. As iron mining, steel plants are often large in scale, covers a wide range of population and therefore the corresponding environmental problems is very conspicuous. leading industries such as the Ma On Shan Town is the steel production industry, of the city's output value of more than 65%, however, each producing 1 t of steel, emissions nearly 20,000 m3 emissions, 50 tons of waste water, 4 t industrial solid waste. According to statistics, in large and medium-sized Tangshan Iron development covering 5280.6 ha, of which opencast mining area 1127.8 ha, Paishi field covering 1939.3 ha, tailings Field 650.2 ha. Rail mining damage farmland 1357.9 ha, woodland 490.5 ha, lawn 47.8 ha, the annual emissions pit water 6161200 t, washing mineral processing wastewater 19342000 t. very fragile mountain ecosystems Originally, the destruction of vegetation in these areas will inevitably lead to soil erosion and landslides caused the risk.


Solutions to environmental problems, first of all need to focus on is the reclamation work. Reduced by reclamation of land, reduce pollution. In Tangshan region has launched a tailings reclamation technology research, Ye Li tailings into the process, mining, elections Pai, rehabilitation soil, vegetation formation of a more complete cycle of mining reclamation operations processes. reclamation through four model tests after three years of reclamation in the small and medium-sized Tangshan Iron reclamation of 1345.9 ha, reclamation rate was 30.26 percent, reclamation economic efficiency 15.5 million yuan, the plant efficiency 196,000 yuan. this test for the Anshan Iron-Dump, and the end of mining reclamation justifications provided technical means.


Second, we must carry out the tailings or waste rock Comprehensive Utilization Research. Many of our iron ore deposits are integrated, waste rock or tailings often contain a variety of useful components. Recovery and extraction of these useful components, not only economically bring receipts, but also can reduce waste rock and tailings environmental pollution. Panzhihua Iron iron ore 13.5 million t annually, while iron ore tailings from the recovery of vanadium, titanium, cobalt, scandium and other useful and rare metal. only the value of iron ore total value of 38.6%, while in the integrated recovery from the tailings vanadium pentoxide, sulfur concentrate cobalt, titanium concentrates, scandium oxide value products such as running more than 60 percent. again if Meishan Iron Mine, mine is buried concentrated, reserves, a large high-grade underground mining iron mine, with an annual output of iron ore 2 million t.

The sulfur content in the ore of around 2.5 percent, direct sintering ingredients, the resulting sulfur dioxide atmospheric pollution and the large area of farmland hazards, and affect the quality of sinter. Shanghai Meishan metallurgical companies make full use of its advantages in resources to mine mineral processing by-product sulfur fine sand production in sulfuric acid as a comprehensive utilization and deep processing, a good way to enhance economic efficiency. Beneficiation use our strong points, and roasting high grade iron slag into the sintered iron ore for the use of its wastewater discharge water as a mineral processing cycle supplementary water, do the "three wastes" in the production process of digestion, variable waste into, victims of IDS. emissions due to choose the "II to the suction" technologyemissions below the state standards, and produce sulfuric acid finished goods meet quality standards at the national level. according to an annual output of 20,000 t of sulfuric acid, can be produced sulfuric acid residue 21,000 t, only sulfuric acid residue in a cost-effective reached 2.31 million yuan.


For more serious environmental pollution must be carried out mine management to formulate the necessary measures, installing and updating the necessary environmental protection equipment. Currently prevailing in this regard is the issue of insufficient funds for the Environmental Protection, the Environmental Protection debt too many old enterprises. Such as the Ma On Shan built City 38, the production of steel more than 8,000 million tons and turned over profits of 6 billion yuan, while investment in environmental protection has debt 2 billion yuan.

The future resource development and environmental protection should be developed in coordination. Enterprises in the new, expanded, and conversion process, we need to strictly enforce the "three at the same time" in order to avoid the emergence of new sources of pollution. A region in the development of economic and social development plan, it must follow the "economic construction, urban and rural construction, environmental planning at the same time, the same pace, synchronous development "three synchronous approach.