From the current point of view, in the field of metallurgical industry production, in order to overcome the limitation of large demand and insufficient supply of resources, iron and steel enterprises have been investigating and studying how to realize the circulation of solid wastes so as to build a circular economy in the iron and steel industry.
Various types of dust and sludge are inevitably produced in the main process of metallurgical production. Waste from dry collection is called dust, and from wet collection is called sludge. Due to the shortage of mineral resources and the decline in grades, the output of sintering dust ash, blast furnace iron ash ash, converter and electric furnace steel smelting dust, steel rolling iron dust sludge, copper metallurgical precipitation sludge, etc. in the smelting production process has continued to increase.
What is sponge iron
Sponge iron, also name as direct reduced iron (DRI), is the resulting product (with a metallization degree greater than 82 percent) of solid state reduction of iron ores or agglomerates (generally of high grade), the principal constituents of which are Metallic iron, residual iron oxides carbon’ and impurities such as phosphorus, sulphur and gangue (principally silica and alumina).
Sponge iron/DRI has gained great prominence in some countries as a substitute of steel scrap (partially) in steel making in electric arc furnace and in induction furnace. Direct Reduction is a metallurgical process of producing sponge iron from iron oxides (mainly from lump iron ores or pellets) directly in the solid phase. The product of this solid state route has a honey comb structure with minute pores. Hence this product is most commonly known as sponge iron/direct reduced iron (DRI). In addition to the metallic iron content sponge iron contains some unreduced iron oxides and gangue. Since there is no separation of impurities in DR process, all the gangue present in the original oxide (silica, alumina, oxides of phosphorous) goes in to the product sponge iron. In fact concentration of these oxides increases due to the removal of oxygen to a level of plus 90%.
Chemical Composition of Sponge Iron
Grade Total Iron Metallic Iron
SiO2 + AI2O3
Sio2 Sulphur Phos Combined total of Pb, Zn, Cu,Sn, Cr,Ni,As
1 Plus 91 Plus 82 5 4 0.02 0.06 0.015 2 89- 91 78- 82 6 4 0.03 0.07 0.015 3 85- 91 76-78 8 6 0.03 0.10 0.015
Hot DRI (HBI)
HBI means briquettes made out of sponge iron/DRI produced in gas based direct reduction processes at elevated temperature by the application of external pressure in a more or less close mould.
Hot DRI in the form of pellets, lumps, fines at a temperature of 650-850 deg C is passed through hot briquetting machine where the product is pressed between the rolls at extremely high pressure to produce highly compacted pillow shaped material called hot briquetted iron (HBI).
While producing sponge iron some amount of sponge fines of minus 4mm is also generated. This sponge fines is briquetted in cold condition using binders in the cold roller press to produce highly compacted pillow shaped material called as cold briquetted iron. (CBI)
The DRI grade chart
Why make sponge iron briquette
For most of the cases in sponge iron briquette making is to deactivate.
Sponge iron is a kind of raw material
1. When using the iron ore to produce
The sponge iron briquette machine
Cold DRI briquette machine
Hot HBI briquette machine
Sponge iron briquette process
What is biomass briquetting
Biomass briquetting is to briquette and carbonize the scattered, light, difficult to store cellulose biomass, turn it to a kind of fuel. Biomass briquetting can increase capacity and calorific value of biomass, improve combustion performance, make the bio waste become a kind of commodity energy source. This conversion technology is increasingly accepted by people around the world now.
What is converter sludge
In the production process of metallurgical enterprises, converter oxygen blowing smelting is a necessary part of the steel making process.
During the converter blowing process, the oxygen injected into the pig iron undergoes an incomplete oxidation reaction with the carbon in the pig iron to form a flue gas containing CO. At the same time, iron and other accompanying metals enter the wet flue gas dedusting system in the form of flue gas as well. The soot carried by the washing sewage is precipitated and exists in the form of water-containing sludge. This is called the converter sludge.
Quick lime powder is a kind of powdery waste produced in the production of the lime kiln. The price of quick lime powder is very low, which is basically less than half of the price of lump quicklime. But in the production process of lime kiln, the production rate of quicklime powder is very high, many of the lime powder kilns have an ash content of more than 20%. The inefficient use of these lime powders will not only cause economic waste, but also cause pollution to the environment.
Coal briquette is a kind of coal product that has been briquetted under certain pressure with certain shapes and physicochemical properties from a coal briquette machine or an extruder machine.
It usually uses coal dust to mix with binder and sulfur-fixing agent as well as some other additives to get the briquette.
Industrial-fired boilers and industrial kilns use coal briquette to significantly increase thermal efficiency and reduce emissions of coal-fired pollutants compared to burning raw coal.
Coal briquetting with the cleaning process and the clean product is suitable for global development and worth encouraging.
By using a coal briquetting machine or a coke briquetting machine, these fine/dust can be easily turned to briquette. One thing in this briquetting process make things become easier, that is – binder.
The coal briquette and coke briquette binders have a dual function in the briquette making process.
1. it can infiltrate the coal particles, form a binder bridge to connect the particles, enhance the interaction between the coal/coke, and bond the particles together.
2. When carbonized, it can form a colloidal body, and the inert components are bonded together to form a high mechanical strength coal/coke briquette.
With the development of the global economy, the gradual depletion of various mineral resources, besides, it also caused a variety of serious environmental problems, these have become factors that constrain the development of the global economy.
Countries all over the world are now doing a lot of work in environmental comprehensive management and developing circular economy. Now the global mainstream is the development and application of energy saving and emission reduction technologies.
Metallurgical briquette producing is an important part of the metallurgical process.
Additives for plastic and pneumatic industry :
Anti-UV Anti-oxidizing agents
Formula for dish-washers
Formula for washing machines
Formulation agents (STPP, perborate…)