Coke for Rock Wool Production

What is coke and how is it made
‘Coke is made by carbonisation of hard coal at high temperature – over 1000 °C – without access of air. Hard coal is used for coke production if possible with low sulphur content and adequate properties for thermal processing. By-products of the coking process include: ammonia, crude tar, crude benzol, coke-oven gas and sulphur.
Coke is formed also during oil processing, which is not suitable for the production of pig iron due to its properties.
Coke emerged also in a natural way, particularly there where coal strata came to contact with hot magma during the geological development.

Coking process
coal handling (coal discharge, sampling, storage in bins)
charge preparation (batching, grinding, mixing, moistening and sampling)
high-temperature carbonisation (coal charging, coking, coke extruding, coke cooling)
coke handling (crushing, screening, sampling and loading onto railway carriages)
cooling and cleaning of crude coke-oven gas and obtaining secondary chemical products

Coke Production

The coke production process takes place in coke chambers. First, selected types of quality coking coals are mixed in a certain ratio in the coal charge, which is subsequently ground and then transported to coal towers. Charge from coal towers is taken by the stamping machine, where it is tamped into large coal prisms. This pressed coal block is inserted horizontally, using the so-called charging board, to the oven of the coke battery, where the block is heated without access of air by an indirect method (thermal pyrolysis) using heating walls of coke ovens. The required temperature of ca. 1,150°C is achieved in heating walls by burning technically pure coke-oven gas. The whole coal prism is gradually carbonised and converted into coke during the coking cycle, which takes from 32 to 34 hours. The final hot coke is extruded using the extrusion machine through a basket of the guiding car to the platform of the quenching car. The quenching car brings this coke under the quenching tower, where coke is cooled by water falling down by gravitation.
The quenched coke is discharged by the quenching car to the coke ramp, from which it is batched to the conveyor belt leading to the rough coke screening. Coke is screened here and foundry coke is loaded onto railway carriages or containers. Blast furnace coke and technological cokes are transported by conveyor belts (after passing the rough screening) to the fine coke screening, where it is sorted by grain size at vibration screening and final coke screening. Final coke types are loaded onto railway carriages, containers and shipped to customers.
A whole number of by-products is formed during coke production, which are significant raw materials for chemical industry. Coke-oven gas is captured during coking, from which the individual chemical products are separated (tar, benzol, amonium sulphate, solid sulphur).

Coal is the main ingredient used to make coke. Iron is produced by inputting coal into a blast furnace. However, coal cannot be put directly into a blast furnace because of all the harmful by-products that come from that. So, there is an intermediate process that occurs. Coal is converted into coke first. Coke is used as fuel in a blast furnace. It plays an important role in the chemical processes that take place in a blast furnace.
Coal is heated to about 1250 degrees Celsius in the coke ovens. This process is referred to as ‘dry distillation’ because these coke ovens are oxygen free, so the coal does not actually burn. This process takes around 18 hours to convert 35 tons of coal into 25 tons of coke.
After heating up the coal into coke, the coke is then unloaded from the oven by a pusher machine. The pusher machine has a pusher arm that puts the coke into a car that takes the coke to a coke quenching tower. Here, the coke is quenched with water. The coke is then taken to a coke wharf, where the remaining water evaporates. A reclaimer then feeds the coke from the wharf to a conveyor belt, which transfers the coke to the crushing and screening station. The finished product is about two-thirds the weight of the original raw material.
During the distillation process, a large amount of gas and smoke is generated, which, after purification, creates coke oven gas, and other by-products such as ammonia, tar, sulfur, naphthalene, and benzol. The creation of coke and the purification of gas are performed completely automated.
Coke makers use a mix of coal to improve the quality of coke they create. A high-quality coal does not generate high pressure on the coke oven, and they also shrink enough so that they are easily removed from the coke oven. The properties of coke are influenced by moisture content and density.
The main use of coke is to make iron. The burning of coal to coke produces carbon monoxide. A touch at the bottom of the furnace allows impurities to flow out of the furnace. This, coupled with the fact that many harmful impurities come from heating the coal is the reason why there is so much pollution that comes from the creation of coke.
Pollution prevention in coke making is focused on reducing emissions from the coke oven. There are many ways to help reduce pollution. One way is to improve the quality of coal feed, so that the coke produced is of higher quality. This helps reduce emissions of sulfur oxide and other pollutants. Another way is to use enclosed conveyors for the coal and coke handling. Also, use many windbreaks and reduce the drop distances. Using higher quality of coal helps reduce the time it takes to convert it into coke, it also helps reduce fuel consumption.

1. Coke for rock wool production

2. Product Features

Rock wool coke has 6 significant characteristics: low water, low ash, low reactivity, high fixed carbon, high calorific value, and high cold and hot strength. Among them, the "double high" characteristics of high fixed carbon and high calorific value fully meet the high quality requirements of high-quality rock wool production for coke indicators, and have become the preferred raw material for the majority of rock wool users to produce high-end rock wool products.