General industrial quality requirements for iron ore

1. steelmaking iron ore (formerly known as open-hearth bonanza)
Ore into the furnace block requirements:
Iron ore for open hearth 50~250mm;
Iron ore for electric furnace 50~100mm;
The iron ore for the converter is 10 to 50 mm.
The ore quality requirements directly used for steelmaking are shown in Table 1 (for magnetite ore, hematite ore, limonite ore).

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2. Iron ore for iron making (formerly known as blast furnace rich ore)
Ore into the furnace block requirements: generally 8 ~ 40mm.
Iron ore for iron making can be divided into: according to the pH of the slag component:
Alkaline ore (CaO+MgO) / (SiO ₂ +Al ₂ O ₃ )>1.2;
Self-fluxing ore (CaO+MgO) / (SiO ₂ +Al ₂ O ₃ )=0.8～1.2
Semi-self-fluxing ore (CaO+MgO) / (SiO ₂ +Al ₂ O ₃ )=0.5-0.8
Acid ore (CaO+MgO) / (SiO ₂ +Al ₂ O ₃ )<0.5
The quality requirements for iron ore used directly in blast furnace ironmaking are shown in Table 2 (applicable to various iron ore type lump ore).

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Acid converter steelmaking pig iron ore P≤0.03%
Alkaline open hearth steelmaking pig iron ore P≤0.03%～0.18%
Alkaline side blowing converter steelmaking pig iron ore P≤0.2%～0.8%
Thomas pig iron ore P ≤ 0.8% ~ 1.2%
Ordinary foundry pig iron ore P≤0.05%～0.15%
High phosphorus cast pig iron ore P≤0.15%～0.6%

3. Need to choose iron ore
For ore or iron ore containing associated beneficial components with high iron content or high iron content but harmful impurities exceeding the specified requirements, beneficiation treatment is required. The selected iron concentrate is sintered or pelletized by batching. After processing, it can be used in the furnace.
Iron ore requirements subject to beneficiation:
Magnetite ore TFe≥25%, mFe≥20%;
Hematite ore TFe≥28%～30%;
Siderite ore TFe≥25%;
Limonite ore TFe≥30%;
For the type of ore industry to be selected, it is usually based on a single weak magnetic separation process and is divided by magnetic iron occupancy. According to China's mine production experience, the general standard is: [next]
Ore type mFe/TFe (%)
Single weak magnetic ore ≥65
Other process ore selection <65
Another classification criterion can be applied to magnetite ore or hematite:
mFe/TFe ≥85 magnetite ore mFe/TFe 85~15 mixed ore mFe/TFe ≤15 hematite ore

In the moving parts, because of the long-term friction caused the wear of parts, and the axial clearance hole wear to a certain extent must replace parts, so the designers choose low hardness material with better wear resistance for the sleeve and bushing at design time, it can reduce the wear of the shaft and the shaft sleeve, or when bushing wear to a certain degree to change, so you can save the cost by replacing the shaft or the seat, in general, the Bush and the seat by interference fit, and axis of the clearance fit, because no matter how cannot avoid wear, can prolong the life of shaft parts, and relatively easy to process; there are also some new the designer does not love this design, that is to increase the cost at the time of manufacture, but after a period of time after use, maintenance or according to this party Method of transformation, but the transformation is likely to cause lower accuracy of the equipment, the reason is very simple, two processing can not be guaranteed some of the center of the seat hole position of the sleeve, in some low speed, radial load and high clearance for better place (such as camshaft) to replace the bearing sleeve (in fact, is also a kind of sliding bearing material requirements), low hardness and abrasion resistance, sleeve bore through grinding and scraping, can achieve high matching precision of oil tank must have a lubricating oil on the inner wall of the sleeve, the lubrication is very important, dry grinding, shaft and shaft sleeve will soon be scrapped, here recommended installation scraping hole wall sleeve so, can leave many small pits, enhance lubrication bushing and bushing is selected according to different types of different mining conditions. The main conditions are: pressure, velocity, pressure velocity product, lubrication condition, load property. Bushing fast and easy to select the best automatic selection.