Slag carrier

From the moment the blast furnace production began until the end of the 19th century, when the productivity of blast furnaces was not very high, pig iron was released into the foundry during the release from the furnace, and slag was sent to a special slag site (slag yard) located directly near the furnace on the ground. After release and curing, the slag was crushed and dumped on wheelbarrows to a dump.

Subsequently, the slag yard began to be covered with cast-iron plates, on which the frozen slag mass was crushed. Thus, a lot of time and physical labor was spent on slag and cast iron cleaning, which restrained the growth of the productivity of blast furnaces.

The problem of uninterrupted mechanized cleaning of slag and cast iron was solved only after the melting products began to be poured into ladles. Thanks to this, the foundry together with the furnace was raised above the zero mark so that pig iron and slag discharged from the furnace could be drained into the ladles installed on the railway tracks under the foundry.

The slag carrier platform is a welded structure. The main bearing elements are curved beams to which the areas are welded, which is the basis of the struts of the support ring and the tipping mechanism.

The platform rests on two biaxial carts. The support ring serves to fit the bucket into it. The support ring is a steel casting, in the walls of which there are oval holes for better air cooling of the walls of the bucket. The support ring is molded as one unit with the support sliders and trunnions.

Tribal sectors are pressed onto the trunnions, which are moved by tribal sectors mounted on the platform and transmit the rotary movement together with the bucket to the support ring.

For fixing and securing the bucket, there are protrusions on the upper shelf of the ring, and ears on the lower shelf.

The bucket is rotated by a flip mechanism driven by an electric motor mounted on the platform through a gearbox and a pair of gears .

Slag ladles work in very difficult conditions - at high temperature and uneven heating in height and wall thickness, which leads to the formation of cracks. Therefore, it is important to choose a rational shape of the bucket. The most rational is the conical shape of the bucket with a spherical bottom, round or oval cross-section.

Buckets are made pouring with steel walls with a thickness of 60 to 100 mm. To reduce thermal deformations and increase endurance, the outer surface of the bucket is reinforced with vertically directed ribs. The inner surface of the slag ladle, unlike the cast-iron ladle, is not lined with refractory bricks, because the slag does not affect the bucket metal like cast iron (liquid cast iron “cuts” it when it comes into contact with metal). Liquid slag, unlike cast iron, even having a high temperature, cannot “cut” the metal body of the bucket upon contact with it. In addition, heat loss by the slag through the walls of the bucket and the likely partial solidification of the slag in the bucket during its transportation from the furnace to the slag dump are not significant. The slag carrier is equipped with a pneumatic and manual brake, an automatic coupler for connecting it to other slag carriers or a diesel locomotive, and a gripper for securing the slag carrier to the racks during tilting of the bucket.

In the middle of the 20th century, slag carriers with a bucket capacity of 11.0 m³ were used, then buckets with a capacity of 16.0 and 16.5 m³ were designed.

Before installing a slag ladle under the furnace for pouring slag into it, the ladle is covered with so-called lime milk from the inside to prevent slag sticking to it. After being discharged from a blast furnace, a train is made up of slag carriers with liquid slag, which is transported by diesel locomotive to a slag dump, which can be located several kilometers from blast furnaces or open-hearth furnaces.

• Cast iron truck

• V.P. Movchan, N.M. Berezhnoi. The basics of metallurgy. Dnepropetrovsk: Thresholds. 2001.336 s.