Poster - 115-017 - Carbon Sequestration - Eng.pptx

Poster - 115-017 - Carbon Sequestration - Eng.pptx

CAPTURE OF THE CO2 FROM GASES OF DRYING IN SETTLING POOLS FOR PROCESS WATER TREATMENT Souza, E.L. (1) Gomes, G.S.L. (2) Assunção, D.D. (3) Pereira, D.F. (4) ABSTRACT During the wet recovery process of steelmaking sludge, non- ‐metallic components present suffer a great soluLon in water treatment of this material. To the content of the metal recovery process occurs without contaminaLon by water saturated with CaO is dissolved in the form of Ca(OH)2, is necessary to remove this hydroxide. The Ca(OH)2, present in the wash water, it forms a layer of CaCO3 when the metal material is dried, reducing their metal content. To prevent this, a study was iniLated to prevent CaCO3 was formed during drying. To prevent the formaLon of this compound moved where it was formed, and drying the smokes rich in CO2, were directed to the seSling pools. The contact of Ca(OH)2 with CO2 to form CaCO3 precipitate out. This precipitaLon reduces the lime content in the water, promoLng cleanliness of the metal material and water purificaLon, recycling about 97% of water and capturing CO2.



Monóxido de Carbono

Lama de Aciaria INTRODUCTION During the steelmaking process, many solid par6cles are generated and dragged in the gas flow generated. These par6cles, for the most part, are steel microspheres formed during the solidifica6on process of the steel droplets sprayed in the gaseous medium during the process. Along with these metallic par6cles are entrained other non- ‐metal, such as slag par6cles (SiO2, CaO, FeO, etc.), these, aFer washing of gases are generated as waste sludge in the steel making process. During the recovery of the metallic content of the slurry procedure, what remains is a compound with a lower mass comprising oxides of iron, calcium and magnesium. These oxides, in contact with water, forming hydroxides. These hydroxides in contact with the fumes of the CO2, form unstable soluble bicarbonates which generate, then insoluble carbonates. These are that precipitate in the boJom of the pools. This enables seJling advantage of three factors: i. allows cleaning of the wash water for reuse thereof; ii. enables carbon sequestra6on by carbona6on reac6on of these oxides; iii. the recovery of these carbonates which can be recycled.

(a) (b) Figure 1 – (a) Products generated by the steel refining; (b) metallic microspheres together with entrained non- ‐metallic material that will form the slurry. Source: Author (2006)

(a) (b) Figure 2 – Steelmaking Mud aspect: (a) original mud; (b) mud aFer shearing, free from fine binders. Source: Author (2006)

(a) (b) Figure 3 – Metal recovery plant: (a) modula6ng plant; (b) concentric gas oven drying the concentrate. Source: Souza, E.L. (2006)

MATERIALS The material used was a steelmaking mud aFer ultrasonic disaggrega6on. EQUIPMENT The equipment was: a waste processing plant (ultrasonic disintegra6on, gravity concentra6on in spirals Reichert, slurry pumps, dewatering screws); oven drying the concentrate; seJling pools; infrared CO2 sensor; pH meters; density of the water meter.

METHODOLOGY AFer ultrasonic disintegra6on material is subjected to a gravity concentra6on Reichert spirals. AFer concentra6on, the tailings containing most of the non- ‐metallic material and most of the water used in the process is forwarded to the decan6ng process. During this process, the solid is decanted in the early stages, the water containing the dissolved hydroxide is redirected to other pools with retorts, where the drying gas of the metal concentrate from the concentric furnace is bubbled through the boJom in counterflow the displacement of water. In contact with the gas, predominantly CO2, hydroxides pass through carbonates forming reac6on, that are poured. The pools are divided into three sec6ons. The first to seJling of par6culate solids directly. The remaining sec6ons are for the forma6on of carbonates and its precipita6on. The measurement of density is performed by a dynamic balloon, that is, the flow passes through a kine6c reducer, which is suspended by a weight reading system, which allows direct calcula6on of the average density of the pulp flow.

Figure 4 – Plant for treatment of mud, steps: i) breakdown of steelmaking mud; ii) concentra6on of the metal content; iii) dewatering the tailings; iv) gas oven for drying the concentrate. Source: Souza, E.L. (2006)

(a) (b) Figure 5 – (a) 3D design of seJling box; (b) seJling box built in the pilot plant. Source: Souza, E.L. (2006)

Figure 6 – Side cut view of the carbonates separa6ng plant: 1) water flowing to the fine precipitates, retort; 2) water box for final purifica6on. Source: Souza, E.L. (2006) 1 2

RESULTS AND DISCUSSION The precipitated material consists essen6ally of calcium carbonate, however, it was noted the presence of Fe II and Mg carbonates. The water in the final pool, aFer passing through all the stages of forma6on of carbonaceous precipitate and decanta6on, has a hardness content of less than 9 mg of Ca(OH)2/L of solu6on. All CO2, generated by a consume of 0.039 m3 C3H8/ton of metallic concentrate, was captured.

(a) (b) Figure 7 – (a) Appearance of metallic concentrate with and without the removal of CaCO3; (b) the cleaning water with the forma6on of CaCO3 (leF) and Ca(OH)2 without carbona6on (right). Source: Souza, E.L. (2006)

(1) Prof. Dr. Erivelto Luís de Souza DTECH – CAP – UFSJ Metallurgical and Materials Eng., Ph.D. (31) 9961- ‐1594

(2) Guilherme Santana Lopes Gomes DNPM - ‐ MG Mining eand Materials Eng., M.Sc.

(3) Divanildo Dias Assunção Fundação Gorceix Environmental Eng. (4) Denise Fonseca Pereira FUPAC – Conselheiro Lafaiete, MG Control and Automa6on Eng.

REFERENCES • Herzog, H. “Carbon Sequestra.on via Mineral Carbona.on: Overview and Assessment”. MIT Laboratory for Energy and the Environment - ‐ US. 2002. • Yamasaki, A.; Iizuka, A.; Kakizawa, M.; Katsuyama, Y.; Nakagawa, M.; Fujii, M.; Kumagai, K.; Yanagisawa, Y. “Development of a Carbon Sequestra.on Process by the Carbona.on Reac.on of Waste Streams Containing Calcium or Magnesium”. Japan. 2008. • Monteiro, J. G. M- ‐S. “Um Estudo sobre AlternaLvas de Sequestro de Carbono; Modelos, Métricas e OLmalidade”. UFRJ/CT/EQ/TPQBq. 2009. THANKS My sincere thanks to DTECH/CAP/UFSJ, Gorceix FoundaLon, TecNouveau Engineering. To my colleagues, partners in this work.