• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.309-310
• /
• 2023

Slag and ash generally have a higher powder degree than portland cement, so workability may deteriorate under the same unit quantity condition, and strength and durability decrease when the unit quantity is increased. At this time, if an aggregate having a low water absorption and an appropriate particle size is used to recover the loss of strength, it can contribute to reducing the unit quantity of the binder. Therefore, for the purpose of improving the workability and strength of non-sintered cement mortar using slag and ash, ferro nikel slag whose particle size was adjusted was used as an aggregate and its applicability was identified. In this experimental condition, it was confirmed that non-sintered cement mortar tends to improve workability and secure strength when ferro nikel slag having various particle size distributions is used as an aggregate. This can be analyzed as the effect of ferro nikel slag material properties including glassy properties and mixing conditions with a wide particle size distribution.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.2
• /
• pp.159-167
• /
• 2022

The present study assessed the micro structure and durability characteristics of ternary blended cement with different types of alkali activators. Ground granulated blast furnace slag(GGBS) and ferronickel slag(FNS) was replaced until 50 % of the weight of cement. In addition, potassuim hydroxide and sodium hydroxide were used for comparing the properties of different type of alkali activator. Ternary blended cement with alkali activators showed higher peak portlandite peak than that of OPC(Ordinary Portlande Cement) and non activated ternary blended cement. Also, there was no new hydration products in ternary blended cement or/and alkali activators. Based on the mercury intrustion porosimetry(MIP) test result, ternary blended cement increased macro pore while alkali activated ternary blended cement modified pore structure and increased microp pore as compared to OPC as control. Combination with alkali activators is desirable to enhance the compressive strength and freeze thaw resistance.

• Journal of Korean Society on Water Environment
• /
• v.34 no.3
• /
• pp.316-327
• /
• 2018

Liquid fertilizers made from livestock manure contain high concentrations of nitrogen and phosphorus and thus are used as a fertilizer. However, excessive use of liquid fertilizer causes eutrophication of agricultural land and nonpoint source pollution. In this study, as a means of lowering the nutrient concentrations, struvite ($MgNH_4PO_4{\cdot}6H_2O$) production from the liquid fertilizer was investigated. When liquid fertilizers produced in Gyeonggido were analyzed, its characteristics differed by region and season, but the phosphorus concentration was commonly lower than that of nitrogen. When $K_2HPO_4$ and $MgCl_2$ were added to the liquid fertilizers, the optimal pH for struvite formation was pH 9.5. For environmentally friendly sources of magnesium and phosphate, ferronickel slag (FNS) and sewage sludge ash (SSA) were suspended in deionized water and extracted by sulfuric acid with various mass ratios. The optimum conditions for extracting FNS and SSA were 4.0 M sulfuric acid and 0.35 mass ratio of sulfuric acid to sewage sludge ash, respectively. For forming struvite, 0.233 L of SSA leachate (SSAL) was added into 0.3 L of liquid fertilizer containing 2,586 mg/L of ammonia and 110 mg/L of phosphate, pH was then adjusted to pH 9.5 using 10 M of NaOH. Afterwards 0.333 L of FNS leachate (FNSL) was added to this mixed solution. After a reaction for 1 hr at room temperature, the remaining concentrations of magnesium, ammonium, and phosphate were less than 50 mg/L, 500 mg/L and 150 mg/L, respectively, and 30 g of precipitates were obtained, most of which were struvite.

• Korean Journal of Environmental Agriculture
• /
• v.33 no.3
• /
• pp.169-177
• /
• 2014

BACKGROUND: The ferronickel and rapid cooling slags used in present study are industrial wastes derived from a steel factory in Korea. These slags are used as almost road construction materials after magnetic separation. However, the use of slag to remove phosphorus from wastewater is still a relatively less explored. The objective of this work was to evaluate the feasibility of ferronickel slag (FNS) and rapid cooling slag (RCS) as sorbents for phosphorus removal in wastewater. METHODS AND RESULTS: Adsorption experiments were conducted to determine the adsorption characteristics of the FNS and RCS for the phosphorus. Adsorption behaviour of the phosphorus by the FNS and RCS was evaluated using both the Freundlich and Langmuir adsorption isotherm equations. FNS and RCS were divided into two sizes as effective sizes. Effective sizes of FNS and RCS were 0.5 and 2.5 mm, respectively. The adsorption capacities (K) of the phosphorus by the FNS and RCS were in the order of RCS 0.5 (0.5105) > RCS 2.5 (0.3572) ${\gg}$ FNS 2.5 (0.0545) ${\fallingdotseq}$ FNS 0.5 (0.0400) based on Freundlich adsorption isotherm. The maximum adsorption capacities (a; mg/kg) of the phosphorus determined by the Langmuir isotherms were in the order of RCS 0.5 (3,582 mg/kg) > RCS 2.5 (2,983 mg/kg) > FNS 0.5 (320 mg/kg) ${\fallingdotseq}$ FNS 2.5 (187 mg/kg). RCS 0.5 represented the best sorbent for the adsorption of phosphorus. In the experiment, the Langmuir model showed better fit with our data than the Freundlich model. CONCLUSION: This study indicate that the use of RCS in constructed wetlands or filter beds is a promising solution for phosphorus removal via adsorption and precipitation mechanisms.

• Journal of the Korean Geosynthetics Society
• /
• v.18 no.4
• /
• pp.243-252
• /
• 2019

Recently, as the utilization of underground space increases, the demand for underground excavation increases. In this study, the concrete mixture with a new material was used to develop and evaluate the stability of the CS-H wall that can greatly minimize the problems of existing wall and minimize the impact of ground depression and surrounding ground that may occur in the future for excavation of over 30 m deep in urban areas. The fiber reinforcement formulation of steel fibers, synthetic fibers, and glass fibers, along with fine aggregate parts of PS-ball and ferronickel, were mixed. The Mixture ratios were determined by conducting slump test compresive strength test, modulus of elastic test, flexural strength test, splitting tensile strength test and conductivity test. As a result of the test, the steel fiber mixture showed very good results compared to other reference values in all items, and it is considered to be the most suitable for the CS-H wall to be developed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.4
• /
• pp.145-151
• /
• 2019

The Physical performance of use materials was evaluated to improve durability of fast-paced repair mortar used at rapid construction sites. The fastening performance and basic performance were evaluated by substituting ferronickel grinding slag residues, rapid settlement, and EVA-based polymer for mortar. As a result, the compressive strength, flexural strength and adhesion strength were increased due to the use of FS Fine Aggregate and RS Fine Aggregate. The chloride ion promotion test of fast-polymer mortar kept the chloride inhibitory performance from 7 days to 28 days when fNS was used less than 50%. Durability degradation due to the use of FS Fine Aggregate and RS Fine Aggregate has not been found, and it is believed that further consideration of economic and long-term durability will be required for use as alternative Aggregate for construction and civil engineering.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.6
• /
• pp.607-618
• /
• 2022

This study involves the development of a Hwangto permeable block for rainwater storage tanks. The permeable products that form continuous voids between Hwangto binders and aggregates are fine milled slag powder, which is an industrial by-product generated during the production of Hwangto and iron, and ferro nickel slag. The properties of Hwangto permeable blocks were studied using recycled resource aggregates. The target quality is based on KSF 2394. The Hwangto permeable block for a rainwater storage tank is made of water-permeable material, and the permeability of the Hwangto permeable block itself is 0.1mm/sec or higher, with a physical performance of over 5.0MPa in flexural strength and over 20.0MPa in compressive strength. The physical properties of Hwangto permeable block for rainwater storage tanks were researched and developed. In order to prevent flooding due to heavy rain in summer and the urban heat island phenomenon due to depletion of ground water, continuous pores are formed in the block to secure a permeability function to prevent rainwater from accumulating in the pavement of the floor, and to prevent slippage for comfortable and safe storage.

• Journal of the Korea Institute of Building Construction
• /
• v.19 no.2
• /
• pp.105-112
• /
• 2019

Fine aggregate made of ferronickel slag(FNS) is similar to natural fine aggregates and is used in concrete structures both domestically and abroad, but its applications and research areas are limited. In this research, in order to expand the availability of FNS and improve the performance of cement mortar products, the applicability of FNS on dry mortar for floor was examined. Experimental results show that FNS improves flow of cement mortar because it has low absorption rate, spherical shape, and glassy surface. Also, the high stiffness of the FNS aggregate itself is considered to contribute to the improvement of cement mortar quality such as crack reduction by improving the compressive strength and shrinkage reducing. In addition, when FNS fine aggregate is applied, it was possible to secure the impact sound insulation performance equal to or higher than that of mortar using natural fine aggregate.