Interests in conversion of macroalgae to bioenergy via thermal treatment, namely pyrolysis or combustion has increased due to their distinctive composition and high photosynthetic rates. The resulting char byproducts could serve as a trove of precious mineral resources. Thermal pretreatment was compared with direct extraction of potassium salts from alga Saccharina japonica using deionized water for use as food additive, agricultural or pharmaceutical applications. Biomass was pyrolysed with fixed bed reactor or combusted with muffle furnace at 300, 450, 600 °C, and extracted using deionized water in shaker at 150 rpm and 30 °C for 2 h. Overall potassium salts recovery efficiency from raw biomass (52.55 ± 2.79%) was relatively lower than from 450 °C chars from pyrolysis (75.30 ± 0.81%) and combustion (62.07 ± 0.56%). Extracts from pyrolysed char at 600 °C had highest purity of KCl which is most abundant mineral in all products. SEM-EDX and ICP-OES elemental analysis confirmed absence of heavy metals such as As, Cu, Cd and Pb in extracts. Ratios of organic to inorganic fractions in extracts from thermally pretreated samples were much lower (∼ 0.1) than that of raw biomass (8.42).

由于其独特的组成和高的光合速率，通过热处理将大藻类转化为生物能的兴趣增加了，即热解或燃烧。生成的焦炭副产物可作为宝贵的矿产资源的宝库。将热预处理与直接从海藻糖精中提取钾盐进行了比较使用去离子水作为食品添加剂，农业或制药应用。用固定床反应器热解生物质，或用马弗炉在300、450、600°C燃烧生物质，并在振荡器中使用去离子水以150 rpm和30°C的温度萃取2 h。从原始生物质中回收钾盐的总效率（52.55±2.79％）相对低于热解（75.30±0.81％）和燃烧（62.07±0.56％）的450°C焦炭的回收率。600°C下热解炭的提取物具有最高的KCl纯度，KCl是所有产品中含量最高的矿物质。SEM-EDX和ICP-OES元素分析证实了提取物中不存在重金属，例如As，Cu，Cd和Pb。经过热处理的样品中提取物中有机物和无机物的比率要比原始生物质的比率（8.42）低得多（〜0.1）。