4.2　Raw Materials

4.2.1　Physicochemical properties of raw materials shall be in accordance with the following requirements:

1　Fe total should be more than 66.5% and fluctuation within±0.5%；SiO2 should be less than 4.5% with fluctuation within±0.2%.

2　The moisture content should be less than 10%.

3　Specific surface area and fineness shall be finalized according to the characteristics of raw materials and requirements for ball formation.The suitable Blaine numbers of raw materials should be in the range of 1800-2000cm2/g and 2000-2200cm2/g for processing in balling discs and balling drums，respectively.

4.2.2　Preparation of raw materials shall be in accordance with the following requirements:

1　Blending facilities shall be employed in the event of using multiple types of raw materials.Raw materials less than three types should be applied for pellet production.And pre-proportioning shall be considered where more than two（including）types of raw materials are used.

2　Raw materials shall be kept in store for 5-7 days operation.For imported raw materials the storage capacity shall be more than 35 days operation and dedicated stockyard shall be established.

3　Where the moisture in as-received materials is higher than the required，the drying system shall be applied.In general，the moisture in dried materials shall be lower than that is required for properly ball formation at least 1% allowing small amount of water added during balling.When the high pressure roller grinding is available in subsequent process，the moisture of dried materials should be controlled to a level of 8%.

4　Drum dryer with downstream solid-gas flow should be used for iron ores drying.The temperature of exhaust gases discharged from the dryer shall be higher than the dew point before entering dust collecting system.

5　The drying system should be designed allowing 100% raw materials to be dried，and meanwhile the bypass system should also be provided.Adequate measures for prevention of adhering and blocking shall be furnished for storage and transportation of raw materials before drying.

6　Raw materials shall be re-ground if their Blaine and fineness are insufficient for proper balls making，and the grinding process shall be finalized based on the characteristics of as-received materials.In this case，wet ball mill grinding and/or high pressure roller pressing or their combination should be applied for pellet plants of large-scale and medium-scale and moist grinding and/or other grinding process for small-scale plants.Equipment for removing metal and foreign matters shall be installed ahead of high pressure roller press.

7　Where the ball mill grinding system is applicable，the ground products should be with Blaine number at the range of 1500-1800cm2/g.

8　The high pressure roller press shall be sized by the Supplier after conducting grinding tests.