Tratamento De Cinza De Casca De Arroz Por Lixiviação Ácida

Abstract

ResumoA casca de arroz é um resíduo amplamente gerado no mundo, é o principal subproduto do beneficiamento do arroz, e tem sido utilizada como biomassa para geração de energia, o que reduz o impacto ambiental causado pela destinação. No entanto, gera outro resíduo, a cinza de casca de arroz (CCA). A CCA é composta basicamente por sílica e carbono. Sendo os elementos traço mais comumente encontrados o sódio, potássio, cálcio, magnésio, ferro, cobre, manganês e zinco. Pelo elevado teor de sílica, é um resíduo com potencial para ser transformado em coproduto para diversas indústrias, porém, dependendo da aplicação pode ser necessária maior pureza. Assim, diversos estudos utilizaram a lixiviação ácida para reduzir o teor de contaminantes ou melhorar propriedades da CCA. Neste sentido, este trabalho teve como objetivo avaliar o beneficiamento de uma CCA residual através do processo de lixiviação ácida. Para isso, foram utilizados diferentes ácidos/concentrações, relações CCA/ácido e tempos de contato. Após estes testes utilizou-se análise elementar por FRX para caracterização química. Os resultados mostraram que o ataque ácido foi efetivo na redução ou eliminação de Fe 2 O 3 , K 2 O, CaO, P 2 O 5 e ZnO para todos os ácidos e concentrações testadas. Sendo que as diferentes concentrações não afetaram a eficiência de remoção. Palavras-chave: Cinza de casca de arroz; Tratamento; Lixiviação ácida. TREATMENT OF RICE HUSK ASH BY ACID LEACHING AbstractRice husk is a solid waste generated widely in the world, it is the primary byproduct of rice processing and has been used as biomass for power generation, which reduces the environmental impact of disposal, but creates another waste, rice husk ash (RHA). The RHA is basically composed by silica and carbon. Since the trace elements commonly found as sodium, potassium, calcium, magnesium, iron, copper, manganese and zinc. Due to high silica content, this is a waste with the potential to be transformed into byproduct for various industries, however, depending on the application it may be required greater purity. Thus, several studies used acid leaching to reduce the leaching of contaminants content or improve properties of RHA. Thus, this study aimed to evaluate the processing of residual RHA through the acid leaching process. For this, we used different acid concentrations, relations between RHA and acid and contact times. After these tests used the elemental analysis by XRF for chemical characterization. The results showed that the acid attack was effective in reducing or eliminating Fe 2 O 3 , K 2 O, CaO, P 2 O 5 and ZnO acids and for all concentrations tested. Since different concentrations did not affect the removal efficiency.

Valorization of rice husk silica waste: Organo-amine functionalized castor oil templated mesoporous silicas for biofuels synthesis

“…Risk residue valorization is a priority for developing countries where it can mitigate health and environmental problems associated with current field burning disposal; [8], [9] uncontrolled burning of rice husk waste releases crystalline silica particles, which when airborne can cause health problems such as silicosis. [10] Rice husk waste is a significant energy source for methane and hydrogen production, [11,12] from biomass power plants, however environmental concerns remain regarding the resulting ash disposal. [13] Ash produced by the controlled burning of rice husk waste contains amorphous silica, a potential precursor for the production of functional materials including silicon carbides, silicon nitrides and zeolites.…”

Auto-Stirring Grains Bed Dryer as an Innovative Efficiency Solution

“…It must use rice husk or biomass as a calorie-producing ingredient; Total drying production cost rate must be lower than the traditional bed dryer, and even the ordinary drying process by drying and utilizing sunlight (open sun drying); Do not require human assistance during the drying process other than one operator who oversees and runs the machine; Firm and has a long useful life investment; Safe in operation; The new system is an attachment to ordinary flatbed dryer so it should utilize the same body/chamber of ordinary one; It must be ensured that the operator or human skin contact involved is a little possible with grains. Grains skin contains very high silica [12] which will cause itching due to the scratching of the skin of grains with human skin, and also the sharp silica properties.…”