Use of metallurgical slag for aventurine glass synthesis

Glass with an aventurine effect in the lead-boron-silicate system has been developed using metallurgical slag. The experimental results are processed based on probability theory and random process methods. A mathematical model of the charge is developed. The role of the slag in the process of glass synthesis is determined.     

The quantitative determination of glass in slag by infrared spectroscopy

Determinations of the glass content of synthetic and blast furnace slags by infrared absorption spectroscopy are described. A linear relationship exists between the calculated infrared absorption R-values and the percentage glass determined by optical microscopy count. The use of an internal standard and a constant grinding time for the slag sample are crucial to obtaining an accurate and reproducible result. The technique is simple, inexpensive, and minimizes time consuming sample preparations such as washings and particle sizings common in the optical microscopy method.     

Mechanism of Phase Formation in Aventurine Glaze

The results of synthesis of aventurine iron-containing low-melting glazes are given, their phase-formation mechanism is considered, and the optimum heat-treatment conditions are determined.     

Volume nucleation of crystals in glass based on blast-furnace slag

The nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied. The type of crystallization (homogeneous or heterogeneous, volume or surface) is revealed for each of nine compositions of synthesized glass. It is shown that the first crystalline phase in a volume-crystallizing glass is perovskite (CaO · SiO₂); in this phase a nucleation of the main phase occurs: melilite (solid solution of gehlinite 2CaO · Al₂O₃ · SiO₂ in akermanite 2CaO · MgO · 2SiO₂). The fundamental characteristics of homogeneous (for a catalizing phase, perovskite) and heterogeneous (for a catalyzed phase, melilite) of crystallization are determined: the steady-state nucleation rate I _st, time of unsteady-state nucleation τ, crystal growth rate U, and activation energy of frictional flow. The temperature dependences of I _st, τ, and U are obtained. Practical recommendations are presented for the use of blast-furnace slag as a raw material for the synthesis of glass and their further utilization.     

低温铁系砂金釉的制备

本实验以硼熔块、钾长石、苏州土、石英、氧化铁和氧化钛为主要原料来试制低温快烧砂金釉。运用单因素试验分析法研究了氧化钛、氧化铁、硼熔块、苏州土、钾长石等主要原料对砂金釉面性能的影响。     

Development of CaO-rich blast furnace slag containing fluorine mica-based glass ceramic coatings

In the present study, Blast Furnace Slag (BFS) waste was evaluated as a sustainable, cost-effective CaO, SiO₂, Al₂O₃ and MgO substitute for inorganic oxides for the production of frit, a raw material for glass ceramic production. Two different frits were prepared to compare a commercially available frit (F-STD) with frit produced using BFS waste (F-BFS). The samples were characterized by XRF, XRD, heating microscopy, dilatometry and TG-DTA to determine the chemical composition, phase formation and thermal properties. The frits were applied on steel using the electrostatic spray method and subsequently thermally treated at 830 °C for 4.5 min. The reference (GC-STD) and partially BFS-substituted glass ceramic (GC-BFS) coatings were examined by XRD, SEM-EDS and ICP-MS experiments. The main crystal phase for both samples was Ni-substituted fluorine mica (KLiNi₂Si₄O₁₀F₂). GC-BFS was slightly more amorphous (70%) than GC-STD (69.1%), which was correlated with the thermal properties of the BFS waste. Likewise, ICP-MS analysis after a boiling citric acid test (ISO 28706-1: 2008) revealed that the GC-BFS had relatively higher chemical resistance. The total release from the reference sample (GC-STD) was 23.556 mg/L, whereas the total release from the sustainably produced sample (GC-BFS) was 21.451 mg/L, which was consistent with the XRD results.     

Preparation of glass-ceramics with low density and high strength using blast furnace slag,glass fiber and water glass

To reduce the production costs of glass-ceramics and broaden the application field of solid waste in steel industry, low-density and high-strength glass-ceramics were produced by using blast furnace slag as the basic material, choosing glass fiber and water glass as the strengthening agents. The effects of glass fiber and water glass on the phase composition, microstructure, apparent density, water absorption and compressive strength of glass–ceramics were investigated. The results show that the rod structure of glass fiber can be retained in the sintered samples and high content of diopside and augite significantly improve the compressive strength of glass-ceramics. Tiny spherical crystalline phases can be obtained for the glass-ceramics soaked in the moderate concentration of water glass. The BGW-2 samples fabricated with 70% blast furnace slag, 30% glass fiber and 4% water glass, exhibit excellent comprehensive properties. The bulk density, water absorption and compressive strength of BGW-2 are 1.76 g/cm³, 2.26% and 68 MPa, respectively. Consequently, using blast furnace slag to prepare glass-ceramics can be another applicable way to utilize blast furnace slag efficiently.     

Synthesis and properties of ferrimagnetic glass-ceramics and glass fibers derived from pyrite slag

Ferrimagnetic nano-crystal glass-ceramics and glass fibers were prepared based on the ferrosilicate glass system of SiO₂–Fe₂O₃–B₂O₃–Al₂O₃ using large amount of pyrite slag (PS) and small quantities of pure chemicals. Two different fabrication methods were employed, eg, annealing and fiber-drawing method, without performing any nucleation and crystallization heat treatments. The influence of PS content on the magnetite spontaneous crystallization is investigated by the X-ray diffraction, FTIR, SEM, and TEM. The X-ray diffraction patterns show the presence of nanometric magnetite crystals in glass matrix. The ferrimagnetic glass fibers with a diameter of about 20 μm were one-step drawn. The magnetic hysteresis loops of the glass-ceramic and glass fiber samples were analyzed using a vibrating sample magnetometer (VSM). Electromagnetic parameters of samples were also examined.     

Preparation and properties of foam ceramic from nickel slag and waste glass powder

The utilisation of nickel slag and waste glass powder as raw materials for preparing foamed ceramic was studied. The influences of the mixture design and foaming-agent dosage on the properties and microstructures of foamed ceramic were investigated in terms of the density, flexural strength, phase composition and micromorphology. Results showed that incorporating nickel slag improved the flexural strength and uniformity of the pore structure. However, owing to the high density of nickel slag, its excessive usage may impact the development of foamed ceramic density and porosity as a side effect. The Na₂CO₃ dosage was another crucial factor determining foamed ceramic properties. A nickel slag content of was 20% and a Na₂CO₃ content of 7% decreased the foamed ceramic density to 0.498 g/cm³, with a corresponding flexural strength of 2.66 MPa and a higher porosity of 80.06%.     

Effect of calcium carbonate on the preparation of glass ceramic foams from water-quenched titanium-bearing blast furnace slag and waste glass

ABSTRACT

Glass ceramic foams were fabricated with powder sintering technology at a low temperature (900°C), using water-quenched titanium-bearing blast furnace slag (WTS) and waste glass as the primary raw materials. Additionally, calcium carbonate, sodium borate and sodium phosphate were chosen as sintering aids to form excellent performance products. The effects of calcium carbonate additions on foaming process, crystal content, morphology and properties of the prepared samples were systematically researched. The research indicates that increasing the calcium carbonate content made the foaming process harder and the pore size got more uniform. Consequently, the compressive strength and bulk density increased, while the porosity and water absorption decreased. The homogenous porous structures and optimal comprehensive properties were achieved with 5–7?wt-% CaCO₃ addition, including a bulk density of 0.79–0.82?g?cm^–3, porosity of 73.13–75.28%, water absorption of 3.29–3.75% and compressive strength of 13.13–13.85?MPa.