Synthesis of Hydrocalumite-like Adsorbent from Blast Furnace Slag using Alkali Fusion

Abstract

Blast furnace (BF) slag, one of the byproducts of iron-and steel-making plants, was converted into a hydrocalumite-like compound using the alkali fusion method. The slag was transformed into the precursor with reactive phases via alkali fusion, after which the precursor was added to distilled water and stirred at room temperature to synthesize the product including a hydrocalumite-like compound. The effects of the mixed ratio of NaOH to the slag (NaOH/slag ratio), fusion temperature, ratio of precursor mass to distilled water volume (W/V ratio) and crystallization reaction time on the product phase were investigated, and the removal abilities of the obtained product for certain ions from aqueous solution was examined. Optimal conditions for hydrocalumite synthesis are a NaOH/slag ratio of 1.6, fusion temperature of 600°C, W/V ratio of 125 g/L and reaction time of more than 24 h. The product could remove more NH4 + , Sr 2+ , F -, PO43-and AsO4 3-than BF slag, while the removal of Cl -, SO4 2-and NO3 -was almost zero. These results suggest that a hydrocalumite-like adsorbent able to remove pollutant ions in aqueous solution can be synthesized from BF slag via alkali fusion.KEY WORDS: blast furnace slag; hydrocalumite-like adsorbent; alkali fusion; cation and anion removal abilities.

Chloride Removal of Calcium Aluminate-Layered Double Hydroxide Phases: A Review

“…The synthesis of CaAl-LDH phases could be affected by various factors such as the species variation of main components, thermodynamic characteristics of starting materials, and reaction routes [ 19 , 27 , 28 , 29 ]. The various factors are determined by the type of synthesis method, temperature, anion, and pH value and so on.…”

“…In this context, the adsorption process with various absorbents has been adopted, owing to the simple operation and cost-effectiveness [ 16 ]. Iron oxides and hydroxides, titanium, and some composites with iron and titanium have been often used as an adsorbent [ 16 , 19 ].…”

Effect of microwaves, ultrasounds and interlayer anion on the hydrocalumites synthesis

“…For hydrocalumite, Ca 2+ and Al 3+ , fixed in a molar ratio of two, are seven and sixfold coordinated, respectively, being the seventh ligand of the Ca-polyhedron a water molecule from the interlayer [5]. Hydrocalumites have been extensively used in the immobilization of toxic cations [4][5][6][7][8][9][10][11], the optimization of concrete properties [2,3,[12][13][14], and, in less extent, for catalysis due to their basic properties [15]. The structure of hydrocalumites collapses at temperatures between 400 and 600°C due to the dehydroxylation of their octahedral layers, giving rise to the formation of an amorphous, basic Ca-Al mixed oxide, Ca(Al)O x , which may be also used as catalyst for organic reactions such as the Meerwein-PonndorfVerley reaction [16], the isomerization of 1-butene [17] or the transesterification of castor bean oil and methanol [18].…”

Preparation of Adsorbent with High Removal Ability for Phosphate Ion from Blast Furnace Slag using Alkali Fusion

“…The synthesis procedure was given in a previous paper [21] . A 2.5 g sample of BFS was mixed with 4.0 g of NaOH powder, and ground to obtain a homogeneous mixture.…”

“…In our previous study, we converted BFS into a hydroxidebased adsorbent, containing hydrocalumite and calcite, using alkali fusion, and confirmed that the adsorbent has high affinity for phosphate from aqueous solution [21] . While this adsorbent is expected to be useful to remove phosphate from aqueous solution, more information is required on its properties before it can be widely applied.…”