PRODUCTION OF POROUS GLASS-CRYSTALLINE MATERIALS BASED ON GLASS CULLET AND CONVERTER SLAG

The study conducted the research aimed to obtaining a porous glass-crystalline materials based on glass cullet and converter slag, which was used as a gas-forming additive. In this work, the chemical and phase compositions of the studied slag were analyzed, and a differential thermal analysis of its sample was carried out. Converter slag was added to the composition of the masses in an amount of 2.5 to 30 wt%, the rest was glass cullet. Вurning of the samples was carried out in the temperature range of 850-925 ° C. For the samples under study, using a sand volumetric meter, the volume was determined and the swelling coefficient was calculated, the compressive strength was determined, and the type of structure, which depends on the average diameter of the prevailing pores, was analyzed. The dependence of the swelling coefficient of the investigated materials on the burdening composition and burning temperature has been established. To obtain porous materials with a swelling coefficient of 2.16-2.67 and uniform fine-porous structure (predominant pore size less than 0.5 mm), it is optimal to introduce converter slag into the composition of the masses in an amount of 10-15 wt%, and the recommended temperature range their burning 850-900 ° C. Analysis of the phase composition of the materials obtained indicates the presence of wollastonite as the main crystalline phase, which, due to the acicular structure of the crystals, has a reinforcing effect and contributes to an increase in strength characteristics. The developed porous glass-crystalline materials can be used as thermal insulation and aggregates in lightweight concrete.

Experimental Investigation on the Effect of Converter Slag Aggregate for Blended Mortar Based on CT Scanning

This study investigated the air aging converter (Basic Oxygen Furnace, BOF) slag aggregate mortar with pulverized fly ash (PFA) and ferronickel slag (FNS). The chemical composition and mineralogical constituents of BOF incorporated mortar were analyzed. Setting time, flowability, compressive strength, and length change were measured to evaluate the fundamental properties of BOF mortar. The X-ray CT analysis was employed to observe the effect of converter slag in the cement matrix visually. The results showed that the hydration of BOF generated a pore at the vicinity of the aggregate, which decreased the compressive strength and increased the length change of mortar. However, the PFA or FNS incorporation of PFA or FNS can decrease the alkalinity of pore solution and subsequently reduce the reactivity of BOF aggregate. Thus, the incorporation of PFA and FNS can be a way to eliminate the disadvantage of BOF, such as volume expansion.

Assessing the Environmental Pertinence of Cobalt Exploitation from Slag in KGHM Mines

As ore quality declines in KGHM mines after continuous exploitation, it becomes increasingly relevant to extract as much economic value as possible from the mined ore while limiting the environmental impact. The recovery of cobalt from converter slag is a possible extraction route that can increase economic output at a limited environmental and logistic cost. Life cycle assessment (LCA) is used to assess the environmental impact of copper exploitation and to compare that impact with the estimated impact of cobalt extraction in the Lubin mine. In most impact categories, Co extraction would be responsible for less than 0.2% of the impact, while increasing economic output by 3.38%. Economic allocation shows that cobalt recovery is environmentally pertinent.

Effects from Converter Slag and Electric Arc Furnace Slag on Chlorophyll a Accumulation of Nannochloropsis sp.

The effects of Ca2+ in converter slag and electric arc furnace slag leaching solutions on CO2 content, the effects of CO2 content in solutions on the accumulation of chlorophyll a of Nannochloropsis sp., and the mechanisms were studied. Results showed that addition of 50 mg/L converter slag leaching solution and 400 mg/L electric arc furnace slag leaching solution (lower than 50 vol% concentration) promoted the accumulation of chlorophyll a of Nannochloropsis sp., while an increased concentration of 70 vol% inhibited its accumulation. The highest concentration of chlorophyll a was obtained on the addition of 10 vol%. With 10 vol% leaching solutions added, chlorophyll a concentration for converter slag reached 4.2 mg/L, 1.45 times as much as that of pure F/2 medium, and chlorophyll a concentration for electric arc slag reached 3.2 mg/L, 1.10 times as much as that of pure F/2 medium. Under the same addition proportion, the promoting or inhibiting effect from converter slag on the accumulation of chlorophyll a of Nannochloropsis sp. was more obvious than that for electric arc furnace slag. The reason for the promotion of chlorophyll a accumulation of Nannochloropsis sp. was that an increase of Ca2+ in the solutions led to an increase of CO2, thereby promoting the photosynthetic rate of microalgae. The study provided new ideas for the green application of solid waste and industrial production of microalgae.

Metallurgical processing of converter slag

Converter slurries at modern metallurgical plants represent a significant part of metal-containing industrial waste with a high concentration of iron. Currently, there is a problem of their utilization and use as raw materials for metallurgy. The purpose of this work is to study the processes of briquetting and recovery of briquetted products, based on a mixture of converter slurries of gas purification and converter slags. When performing experimental studies on the preparation of sludge briquettes from a mixture of converter sludge of gas purification and converter slag, their metallization and reduction melting in laboratory conditions, the optimal composition of the components of the mixture of converter slag and gas purification sludge was determined by the percentage of iron, which is appropriate for use as a raw material for steel smelting. Experimental studies on the preparation of sludge-coal mixtures from dispersed metal-containing and carbon-containing industrial waste with stoichiometric coal consumption for the recovery of extracted metals have proved the possibility of obtaining sludge-coal briquettes, which are further subjected to metallization and reduction melting. Sequential processing of dispersed production waste, namely drying, metallization and reduction melting, allowed us to obtain at the final stage a metal sample that corresponds to high-quality steel in its composition. Based on the analysis of the results of experimental studies, the technology of reducing melting of metal-containing waste has been developed. As a result of the implementation of the technology, high-quality steels and alloys can be obtained without carburizing the metal, bypassing the production stages of cast iron and high-carbon alloys. The content of harmful impurities of sulfur and phosphorus meets the technical requirements of high-quality steel. The proposed technology for processing slag and sludge from oxygen-converter production will reduce the volume of accumulated production waste.