Tecnologia em Metalurgia, Materiais e Mineração
Tecnologia em Metalurgia, Materiais e Mineração
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Ruberlan Gomes da Silva; Marcelo Seckler; Sonia Denise Ferreira Rocha; Daniel Saturnino; Éder Domingos de Oliveira

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Potassium chloride (KCl) accounts for most of the potassium (K) used in world agriculture and represents 96% of the world potash capacity. The other 4% includes potassium sulfate (K2 SO4 ), potassium nitrate (KNO3 ) and potassium-magnesium based salts. In this sense, the prediction of the solubility of electrolytes in aqueous solutions is important to provide data for processes that extract potassium salts from multicomponent brines. In this work, Pitzer´s and Harvie´s models were used to calculate the amount and composition of crystallized salts after water evaporation. The process involved four crystallization steps starting from multicomponent brines represented by the quinary Na-K-Ca-Mg-Cl aqueous system at 20°C. The temperature of 20°C was chosen because it is the average process brine temperature in many dry salt lakes. The Pitzer´s and Harvie´s models allowed performing a material balance in solar ponds producing saleable salts like sodium, potassium, magnesium and calcium chlorides.


Crystallization; Potassium; Quinary Na-K-Ca-Mg-Cl Aqueous System.


O cloreto de potássio (KCl) é uma das principais fontes de potássio (K) usada na agricultura e corresponde a 96% do consumo mundial desse nutriente. Os outros 4% incluem o sulfato de potássio (K2 SO4 ), nitrato de potássio (KNO3 ) e os sais duplos de potássio e magnésio. A previsão da solubilidade dos eletrólitos em soluções aquosas é importante na estimativa dos parâmetros de processos da rota de processo a ser usada na extração seletiva dos sais de potássio presentes em salmouras multicomponente. Nesse sentido, os modelos de Pitzer e Harvie foram usados nas estimativas das quantidades e das composições dos sais cristalizados após evaporação da água. A rota de processo envolve quatro etapas de cristalização de uma salmoura representativa do sistema aquoso quinário Na-K-Mg-Ca-Cl na temperatura de 20ºC. A temperatura de 20ºC foi escolhida por ser a temperatura média das salmouras verificadas nos salares Andinos. Os resultados obtidos com os modelos de Pìtzer e Harvie permitiram a elaboração do balanço de massa e energia das piscinas de evaporação e obtenção dos sais comerciais: cloretos de sódio, potássio, magnésio e cálcio.


Cristalização; Potássio; Sistema Aquoso Quinário Na-K-Ca-Mg-Cl.


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