5.4　Distributing，Ignition and Sintering

5.4.1　The segregated distributing shall be adopted for large and medium scale straight line sinter machines.

5.4.2　The sinter machine shall be large sized and its specification shall match with the blast furnace.

5.4.3　One large sized sinter machine and no more than two medium or small sized sinter machines shall be set up in the sintering and cooling room.

5.4.4　The hearth layer facilities shall be set up for the sinter machine.The storage time of hearth-layer material should be 1-2h，and the depth of hearth layer material on the pallet of sinter machine should be 20-40mm.

5.4.5　Deep-bed sintering process shall be adopted for large-scale and medium-scale sinter machines.The bed depth（including hearth layer depth）should be greater than or equal to 600mm when iron ore concentrates are major raw materials.The bed depth should be greater than or equal to 700mm when iron ore fines are the major raw materials.

5.4.6　Unpowered hot air supply mode should be adopted when hot air sintering is adopted.

5.4.7　When siderite or limonite sintering is adopted，a drying zone for preheating mixture should be set up before ignition.

5.4.8　Ignition temperature of mixture should be 1050℃-1200℃，but the ignition temperature of special raw materials shall be determined according to the test results.Ignition time should be 1-1.5min.Various kinds of gases which are mentioned in item 3 in 4.1.3 of this specification should be adopted as ignition fuels for large-scale and medium-scale sinter machines.Coal fines and heavy oil should not be used for ignition.When coke oven gas and natural gas are adopted as ignition fuels，the specific consumption of gas should be smaller than or equal to 0.065GJ/t-s.When convertor gas is used as ignition fuels，the specific consumption of gas should be smaller than or equal to 0.08GJ/t-s.When BF gas is used as ignition fuel，the specific consumption of gas should be smaller than or equal to 0.16GJ/t-s，and the ignition and afterheating furnace with coal gas and air preheating should be adopted.

5.4.9　The size of sinter cake after crushing shall be smaller than or equal to 150mm.

5.4.10　Hot sinter screen should be cancelled for the sintering process.

5.4.11　When there are hot sinter return fines，they should be directly proportioned at the discharge end of sinter machine，and the hot sinter screen shall be deviated from bin center.