Disposal of slag of refined ferrochromium by obtaining a sintered and carbonized construction products

Abstract

The article investigates the material composition of refined ferrochromium slag. It has been confirmed that the main compound in the slag is dicalcium silicate. The disposal problem of self-disintegration slag in the current production of refined ferrochromium can be solved by controlling its basic capacity with obtaining stabilized lump slag that is not influenced to silicate decomposition. This became the basis to researches the production of non-disintegrating burnt construction products from slags using low-melting silicacontaining additives that reduce the slag basicity. Briquettes roasting containing from 20 to 30% additives in the temperature range of 1200-1225 °C showed the possibility of obtaining ceramic construction products. Material analysis of the slag also showed that the slag components, such as calcium oxide and magnesium oxide, are compounds prone to the formation of carbonates, which leads to the setting between the slag particles. Which makes it possible to obtain construction products in the process of autoclaving processing of bricks from the slag in the carbon dioxide environment. The influence of fineness, slag moisture, and the dwell time of products in an autoclave in the carbon dioxide environment on the strength of the resulting pellets were evaluated in this paper. It was determined that moderate humidity, in addition to increasing ductility during pellet molding, also increases the strength of products after carbonization. Excessive grinding of slag negatively affected on the quality of the pellets. The increase in compression force during the pellets formation, on the contrary, increased the strength of the products. An increase in the duration of carbonization at constant pressure had a positive effect on the strength increase of pellets.

Environmental characterization of ferrochromium production waste (refined slag) and its carbonization product

“…Another sample («bulk brick sample») was a piece of a «brick», that was obtained by carbonization experiment, which collected earlier from the same slag dump [ 8 ]. In this paper, the material composition of the initial slag and the carbonized product obtained for their comparison.…”

“…Firstly, disposal and storage of the wastes occupies a large area causing pollution of soil and wastewater with heavy metals indicating the increase of charges for environmental damages of plants and factories every year. The amount of the deposited man-made wastes (refined ferrochrome slag) in the territory Ural Mountain massive is roughly 40 million tons (ferrochromium wastes from Aktobe Ferroalloys Plant, Serov Ferroalloy plant, Klyuchevsky ferroalloy plant, Chelyabinsk Electrometallurgical Plant) [ 8 , 9 ].…”

“…The usage of refined slags is mostly limited in cement industry. However, the significant restrictions for usage of slags (ferrochrome) are the presence of free magnesium oxide and chromium oxides in their mineral composition [ 8 ].…”

Prospects for the Extraction of Chromium From Slag Ferrochrome Production by Acid Method

“…Ferrochrome slags are characterized by a high content of magnesium oxide (MgO), the amount of which varies between (7.0-45%) [15,16]. The chemical and material composition of ferrochrome slags is not constant and depends on the quality of the raw material used and the variety of ferrochrome produced [17][18][19].…”

Modification of microstructure of LD slag for recovery of hybrid flux material

“…The expansion is associated with the cracking of the structures over some time. The expansion is also caused due to the presence of free MgO (periclase) which is the cause of delayed expansion and cracking [8][9].…”