Abstracts Book - IMRC 2018

• SF5-O002
SYNTHESIS AND EVALUATION IN THE CO2 CAPTURE PROCESS OF
MODIFIED LITHIUM SILICATES PRODUCED FROM STEEL
METALLURGICAL SLAGS
Walther Dario Bejarano Peña 1 , Brenda Alcántar Vázquez 1 , Rosa María Ramírez Zamora 1
1 Instituto de Ingeniería (Universidad Nacional Autónoma de México), Ingeniería Ambiental,
Mexico.
Alkaline ceramics are promising CO 2 captors due to their high regeneration
capacities, great CO 2 uptake values and fast adsorption/desorption kinetics. In
this group of materials, Li 4 SiO 4 has shown good adsorption efficiency at high
temperatures (500-800°C), fast adsorption kinetics, and high thermal,
mechanical and chemical stability after various adsorption/desorption cycles.
Furthermore, an important advantage of this material is that can be synthetized
using several wastes and industrial byproducts. Therefore, the aim of this work
is to synthetize and evaluate the CO 2 capture efficiency of lithium silicates, with
and without modification with K 2 CO 3 , produced using steel metallurgical slags
as raw material. Li 4 SiO 4 synthesis was carried out mixing Li 2 CO 3 and the slag as
SiO 2 source (2.1: 1 moles ofLi 2 CO 3 : SiO 2 ) at 900°C for 4 hours using a
temperature ramp of 5°C min -1 . Afterwards, potassium salt was mixed (10-30%
of K 2 CO 3 to the synthetized Li 4 SiO 4 ). Dynamic and isothermal thermogravimetric
experiments were performed changing the CO 2 concentration in the gas stream
5% to 20% v/v, with N 2 as balance. In addition, kinetic parameters were obtained
according to the Avrami-Erofeev model and the cyclabitlity was also studied. XRD
results revealed that not only Li 4 SiO 4 was produced, but also β(beta) and
γ(gamma) LiAlSiO 4 , and Fe x+y Li 1-x Mn 2-y O 4 spinels. Thermogravimetric results
showed that increasing the potassium content in the material decreased the CO 2
capture rate and capacity. The best CO 2 intakes were obtained at 600°C (97.6
and 104.6 mgCO 2 g ceramic -1 , with CO 2 concentrations of 20 and 5% v/v
respectively), using the Li 4 SiO 4 modified with 20 wt% of K 2 CO 3 . The sintering
effects were observed at 680°C and then the loss of sorption capacity was
detected at 700°C.
Acknowledgment: The authors thank Leticia García for her technical assistance
in the laboratory
Keywords: Carbon dioxide, Lithium silicate, Metallurgical slag
Presenting authors email: WBejaranoP@iingen.unam.mx