In 1996, the country selected 219.97 million tons of iron ore, accounting for 85.2% of the country's iron ore original ore 25.22 million tons. The iron ore produced iron ore concentrate was 85.857 million tons, of which the key ore processing plant processed 10.961 million tons of ore, and produced iron ore fines of 41.58 million tons, accounting for 48.4% of the national iron concentrate powder production.
a) ore crushing
China's concentrating plants generally use crushing, crushing and fine-breaking three-stage crushing process to break iron ore. The coarse-breaking multi-purpose 1.2m or 1.5m rotary crusher is used in the 2.1m or 2.2m standard conical stone crusher, and the 2.1m or 2.2m short-head cone crusher is used for fine breaking. Through the coarse ore, the blockiness is not more than 1m, and then it is crushed by medium and fine, and sieved into the final product of the ore grain size less than 12mm.
b) Grinding process
Most of China's iron ore grinding process uses two-stage grinding process, and small and medium-sized ore dressing plants use a grinding process. Due to the use of fine screening and re-grinding new processes, in recent years some concentrating plants have changed from two-stage grinding to three-stage grinding. The grinding equipment used is generally small, the largest ball mill is 3.6m×6m, the largest rod mill is 3.2m×4.5m, the largest self-grinding mill is 5.5m×1.8m, and the gravel mill is 2.7m×3.6m.
The classification after grinding is basically a spiral classifier. In order to improve efficiency, some concentrators use hydrocyclones to replace the secondary spiral classifier.
c) Sorting technology
Magnetite ore dressing
It is mainly used to select low-grade "Anshan-style" magnetite. Due to the strong magnetic properties of the ore and good grinding, the domestic magnetic separation plant adopts stage grinding and multi-stage grinding process. For the coarse-grained magnetite, the former (a section of grinding), fine-grained and fine-grained inlays are used. The magnetite uses the latter (two or three stages of grinding). The series of permanent magnetization developed by China has made the magnetic separator realize permanent magnetization. 70 years later, due to the magnetite concentrator in the country to promote a fine sieve and then grinding the new technology, the concentrate grade increased from 62% to about 66%, to achieve the requirements of the Ministry of metallurgical industry proposed concentrate grade of 65%.
4) Sintering pellet technology
Sintering technology is the main means of man-made rich ore in China. In 1996, a total of 196.956 million tons of man-made rich ore were produced, of which 94.859 million tons were key enterprises, accounting for 58.9%, and 63.37 million tons were local state-owned enterprises, accounting for 38.1%.
China has reached a considerable level in the technology of fine concentrate sintering. As early as the early 1950s, Angang successfully changed the acid sinter production method to the alkaline sinter production method on the sintering machine, and solved the problem of fine concentrate sintering in the world with slaked lime or quicklime as the flux.
The equipment level of the sintered pellets has also improved. There are 419 sintering machines in the country with a total area of ​​15522 m2, of which 22 are sintering machines of 130 m2 or higher, with a total area of ​​4107 m2; 197 sets of sintering machines of 24 to 129 m2, with a total area of ​​9387 m2; 200 sets of sintering machines of less than 24m2, with a total area of ​​2028m2. The 300m2 sintering machine put into operation at Maanshan Iron and Steel Plant on February 24th, 1994 is the largest modern sintering machine designed, manufactured and constructed by ourselves in addition to Baosteel.
The main technical and economic indicators for sintering in 1995 were: utilization factor 1.36t/(m2·h), sinter grade 53.00%, sintering machine calendar operation rate 80.94%, sinter qualification rate 84.92%, worker labor productivity 2170t/ (h·a).
Table pad description editor
1, in the use of home or office environment, this product can be very good to protect your desktop and mesa, to your furniture and personal bring warm protection.
2, soft glass material resistant to high heat, cold resistant, resistant to acid, alkali, resistance to stress, anti-static, shock resistance, tensile resistance, aging resistance, good light transmission, the use of long life
Table 3, soft light, fluent writing, fast, safe and convenient access to information, help to improve banks, schools, government agencies, corporate documents processing efficiency, and to reduce the cost
4, the restaurant can reduce the cost of cleaning, add elegant appearance of the restaurant. For personal office, warm in winter and cool in summer, elastic, with flame retardant, insulation, moisture resistance, heat insulation, sound insulation, corrosion protection, anti shock, deformation, fracture, anti light, anti fade, weatherability;
5, with anti-static, in the telecommunications, electronics, computer companies, the use of precision instruments on the desktop is an essential product. Now many of the computers used by the company have been replaced by a glass desktop, with a soft glass replacement.
Table mat features
The main table mat is made of antistatic material and dissipative static material, such as rubber. The surface layer is about 0.5mm thick dissipative electrostatic layer, the bottom layer is about 1.5mm thick conductive layer. Commonly used for 2mm double layer composite structure. Table mat use time lasting, has good acidproof, anti alkali, anti chemical flux properties, and wear resistance, easy cleaning. Conductive mat is made of high quality conductive materials, synthetic rubber.
The material and the characteristics of the crystal table mat. Come and learn about: first we know oh, soft glass, also known as the crystal plate: is a new generation of high-tech products, it replaces the traditional glass heavy fragile, wounding disadvantage outside it has a lot of advantages.
It is suitable for the dining table, desk, desk, bedside table and all the table. The high degree of transparency, and can heat the soup, tea, cold resistance, weight, non-toxic and tasteless, green environmental protection.
After scientific design, the use of imported PVC new health and environmental protection materials.
The characteristics of high resilience and high resistance to compression and compression can be suitable for a variety of environments.
It has the characteristics of non toxic, soft and transparent, safe insulation, easy cleaning and so on.
The overall heat deformation, high temperature resistance, chemical stability, non stick paint, aging is not easy.
Crystal board can be quite furniture long service life; effectively prevent burns, cuts, scratches and other external damage, make your furniture gets more effective protection.
A glass plate is pressed on a lot of desk, which is convenient for writing. Now, a new type of material is soft glass instead of glass become the people's favorite. At work, it is widely used in electronics, chemistry, pharmacy, food factory, garment factory, working platform, the surface of a variety of office machines, etc.. Family life, it is widely appeared in the glass surface, can not only reflect the true nature of the glass, fashion, and can prevent the glass furniture surface scratch.
Table mat/pvc mat made of material
1) material: PP/PVC
2) material: soft PVC
3) material SBR PVC/PP+EVA/ or natural rubber, etc
4) material: soft glass
5) PVC foaming [1]
6) material: crystal plate
9) material: chemical fiber
10) material: Plush
Role of table mats
In daily life, table mats to the people's life brings convenience, for example, can be used in the table, table, desk pad can not only protect desktop is not hot imprint, is not hot off color and hands up will give a person a kind of comfortable feeling, in addition to the dinner table can also be used for desk, coffee table, a few party, desk, ark of the head of a bed, as long as the table, can use table mat.
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