No abstract

In this study, the effects of temperature and acid concentration on the dissolution of the sulfated and ground after sulfation phosphate samples in sulfuric acid solution obtained after flue gas desulfurization were investigated and the results were compared for both samples. It was observed that the dissolution rate increased as the temperature and acid concentration increased during the dissolution of sulfated and ground after sulfation phosphate samples. It was shown that the dissolution reaction can be divided into two regions, with different rate controlling steps for both samples. The controlling step was determined as pseudo-first order reaction at low conversions and diffusion through the product (ash) layer at high conversions.Bu çalışmada, baca gazı desülfürizasyonundan elde edilen sülfatlanmış ve sülfatlanma sonrası öğütülen fosfat örneklerinin H2SO4 çözeltisinde çözünürlükleri üzerine sıcaklık ve asit konsantrasyonunun etkileri incelendi ve her iki örnek için elde edilen sonuçlar karşılaştırıldı. Sülfatlanan ve sülfatlanma sonrası öğütülen fosfat örneklerinin çözünmesi esnasında sıcaklık ve asit konsantrasyonu arttıkça çözünme hızının arttığı gözlendi. Çözünme reaksiyonunun her iki örnek için farklı hız kontrol basamaklarına sahip iki bölgeye ayrılabileceği görüldü. Kontrol basamağının düşük dönüşümlerde yalancı birinci mertebe reaksiyon, yüksek dönüşümlerde ürün (kül) filminden difüzyon kontrollü olduğu belirlendi.

No abstract

Boron ores are some of Turkey's most important underground riches. Tincal (Na 2 B 4 O 7 ‚10H 2 O), having the largest deposit, originally contains clay minerals such as illite and montmorillonite. One of the most important problems in refined borax production is separating tincal from the clay minerals, which are in a colloidal state in an aqueous solution and cannot be filtered. To separate clay particles, various additives are used as coagulants and cause both increasing production cost and borax loss. In this study, the reactor waste forming during borax production from tincal ore was dissolved in distilled water, CO 2 -saturated water, and SO 2 -saturated water to recover its B 2 O 3 contents, to investigate dissolution kinetics, and to determine the filtration conditions in these dissolving media. The dissolution kinetics of tincal waste were investigated by choosing the temperature as a parameter, and it was found that activation energies and Arrhenius constants were 62.2 kJ mol -1 and 1.8 × 10 10 for SO 2 -saturated water and 24.5 kJ mol -1 and 1.6 × 10 4 for CO 2 -saturated water, respectively. On the other hand, the effects of passing SO 2 and CO 2 gases through a tincal solution on spoiling the colloidal state of clay minerals were studied by using the temperature and stirring time for dissolution as parameters. It was seen that the colloidal state could be spoiled by passing SO 2 or CO 2 gases through the suspension. The filtration rate increased by increasing the temperature and stirring time for dissolution when SO 2 -saturated water was used, but filtration was difficult in CO 2 -saturated water and impossible in distilled water.