The molten slag covered by this Standard is a slag material manufactured for the purpose of efficient utilization of the municipal solid waste, sewage sludge, etc. in the melt-solidifying facilities, and includes the following.

Molten slag is synonymous with melt-solidified material.

a) The molten slag produced in private melt-solidifying facilities which are entrusted by the municipal authorities to treat the municipal solid waste, or that produced when municipal solid waste is treated together with industrial waste whose reuse is approved by the municipal authorities.

b) The molten slag subjected to treatment such as magnetic selection, particle size adjustment, etc. or property modification in the melt-solidifying facilities or separate facilities.

Molten slags are classified into granulated slag, air-cooled slag and slow-cooled slag.

In this Standard, the term "slow-cooled slag" refers to both the air-cooled slag and slowcooled slag.

NOTE 1 Iron and steel slag is either a blast furnace slag produced in manufacturing of pig iron or a steelmaking slag produced in manufacturing of steel, the former being further classified into air-cooled blast furnace slag and granulated blast-furnace slag, depending on the cooling method used, and the latter into convertor-system slag and the electric furnace-system slag, depending on the steel manufacturing process by which the slag was produced.

NOTE 2 Iron and steel slag for road construction may be produced from blast furnace slag and steelmaking slag in a mixture or individually for use as a base course material, or produced from steelmaking slag for use as an aggregate for hot laid asphalt mix or bituminous stabilization.

NOTE 1 For the iron and steel slag, there are the blast furnace slag that is produced in the pig iron manufacturing process and the steelmaking slag that is produced in the steel manufacturing process.

The blast furnace slag is classified into the air-cooled blast furnace slag and the granulated blast furnace slag according to the difference in cooling process.

The steelmaking slag is classified into the convertor-system slag and the electric furnace-system slag according to the difference in manufacturing methods of steels.

NOTE 2 In the iron and steel slag for road construction, there is one that is manufactured for the base course material using blast furnace slag and steelmaking slag as material, singly or in combination, and the other that is manufactured for the aggregates to be used for the hot laid asphalt mix and the bituminous stabilization (heating mixture) using steelmaking slag as material.