Because there are a lot of lean ore (accounting for 97.5% of the total reserves) and paragenitic ore in Chinese iron ore, thus most of iron ore needs mineral processing before smelting.

　　 Feed iron ore of the whole country in 1996 was 214 970 000 tons, accounting for 85.2% of 252 280 000 tons green ore. Feed iron ore produces 85 857 000 tons iron ore concentrate, and the main concentration plant deals with 109 610 000 tons green ore, produces 41 580 000 tons iron ore concentrate, accounting for 48.4% of the yield of iron ore concentrate of the whole country.

(1) Ore crushing

　　 Concentration plant of our country usually adopts three crushing processes---- coarse breaking, medium breaking and fine breaking to crush iron ore. Coarse breaking often adopts 1.2 m or 1.5 m gyratory crusher, medium breaking uses 2.1 m or 2.2 m cone crusher with standard type, and fine breaking adopts 2.1 m or 2.2 m cone crusher with short-head type. Block size of mine ore through coarse breaking is not more than 1 m, then through medium and fine breaking, sieves into the end product less than 12 mm and sends it to grinding ore bin.

(2) Grinding process

　　 As to grinding process of iron ore in China, most concentration plants adopt grinding process with two segments, and medium and small concentration plants adopts grinding process with one segment. Because of adopting new technology of fine screen regrinding, some concentration plants have changed grinding process with two segments into three segments in recent years. Grinding equipment is often very small, the biggest ball mill is 3.6m×6m，the biggest rod mill is 3.2m×4.5m, the biggest autogenous mill is 5.5m×1.8m，and pebble mill is 2.7m×3.6m.

　　 Spiral classifier is used to classify after grinding ore. In order to improve efficiency, a part of concentration plants replace twice spiral classifier with hydrocyclone.

(3) Separating technology

　　 1.Magnetite separation

　　 It is mainly used to separate magnetite with low grade and “Anshan type”. Because mine ore has strong magnetic property and is easy for grinding and separating, domestic magnetic separation plants all adopt stage grinding and multi-stage grinding process. As for magnetite embedded with coarse particles, we adopt the former (one-stage grinding process), as for magnetite embedded with fine and microfine particles, we often adopt the latter (two or three stages grinding process) (figure 3.2.23). Magnetization of serialization developed by our country makes magnetic separator magnetization. After 1970s, new technology of fine screen regrinding has been popularized in magnetite concentrator of the whole country, concentrate grade has been improved from 62% to 66% and realized the requirement that concentrate grade should reach to 65% put forward by Ministry of Metallurgical Industry.

　　 2.Mineral processing of weak magnetic iron minerals

　　 It is mainly used to separate hematite, limonite, specularite, siderite, martite or mixed ore, that is “red iron ore”. This kind of ore has low grade, fine embedded particels, complex mineral composition and difficult for separating. After 1980s,mineral processing technology improved the research on process flow of roasting-magnetic separation, wet strong magnetic separation, weak magnetic flotation and gravity separation, equipment and new variety of agents, and improved concentrate grade and metal recovery. For example, Concentration Plant in An’gang adopts new process flow of weak magnetic----strong magnetic----flotation and makes exciting chievements.

　　3.Mineral separation of polymetallic ore

　　 This kind of ore has complex composition and many types, so adopting method, equipment and process are also different. For example, iron ore in Baiyun’e’bo adopts different processes such as reverse flotation----mutiple gradient magnetic separation, flocculation flotation, weak magnetic----reverse flotation-----strong magnetic separation, weak magnetic------direct flotation, roasting magnetic flotation to improve recovery rate of iron and recycle rare earth oxides. Iron ore in Panzhihua gets 53% vanadium-iron concentrate through magnetic separation, and tailings after magnetic separation gets titanium concentrate and cobalt pyrite concentrate and recycles titanium and cobalt through weak magnetic scavenging------strong magnetic separation------gravity separation-----flotation-----dry electric separation.Iron or in Daye adopts weak magnetic, strong magnetic and flotation to recycle iron, copper, cobalt and sulfur and so on.

(4) Sintering pellet technology

　　 Sintering technology is the main means for artificial enriched ores in China which produced 160 956 000 tons artificial enriched ore in 1996, and key enterprises produced 94 859 000 tons and accounted for 58.9%; local national enterprises produced 61 337 000 tons and accounted for 38.1%.

　　 Sintering technology of fine concentrate in our country has reached corresponding level. An’gang succeeded to change acid sinter making method into alkaline sinter making method about sintering machine in the early of 1950s, and was the first one to use hydrated lime or quick lime as flusing agent and resolve the problem of sintering of iron ore concentrate.

　　 Equipment level of sintering pellet also has been improved, there are 419 sintering machines in the whole country and the total area is 15522m2. There are 22 sintering machines with more than 130m2and the total area is 4107m2; there are 197 sintering machines from 24～129m2and the total area is 9387m2; there are 200 intering machines with less than 24m2and the total area is 2028m2. Sintering machine with 300m2 put into operation in Ma’anshan Steel Plant on Februrary 24, 1994 is the biggest modern sinstering machine designed, manufactured and built by itself besides Baoshan Iron & Steel Plant.

　　Main techno-economic indexes of sintering of the whole country in 1995: utilization coefficient is 1.36t／(m2·h)，grade of sinter is 53.00 %, calendar operation rate of sintering machine is 80.94%，percent of pass of sintering ore is 82.92%, and worker labour productivity is 2170 t／(h·a).