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Abstract：
This paper investigates the enrichment of gold through combustion and ash-leaching techniques utilizing woody biomass as a fuel source. It delves into the formation of gold in ashes derived from the fixed grate combustion of pelletized woody biomass containing noble metals, conducted at a pilot-scale boiler. The biomass sample was gathered from a brownfield land at an abandoned mining area, avoiding induced phytoextraction. The fuel contained <0.05 mg/kg gold, while the bottom ash, after heat exchanger ash, deposited ash, and fly ash contained 1.52 mg/kg, 1.99 mg/kg, 2.64 mg/kg, and 3.52 mg/kg of gold, respectively. Although the amount of fly ash is lower compared to bottom ash, the concentration of gold is the highest in fly ash, which follows the after heat exchanger ash and bottom ash. The concentration of gold was enriched by a three-stage procedure of water leaching, acid leaching (10 % HCl), and alkaline leaching (5 % NaOH), after which 12.1 mg/kg and 12.6 mg/kg gold was found in the residues obtained from leached bottom ash and deposited ash, respectively. SEM was utilized to depict the morphology of gold, which appears in bottom ash as individual neat particles with a purity higher than 98 %. Pure gold particles in the size of 1-2 μm are presented in the after heat exchanger ash; meanwhile, gold in fly ash is primarily associated with potassium, sodium, sulfur, and oxygen. The findings in this study pave the way for reclaiming gold from bio-ores as well as assist in better understanding the formation of this precious metal in these secondary resources.
摘要：
本文研究了利用木质生物质作为燃料来源，通过燃烧和灰分浸出技术富集金。它深入研究了含有贵金属的粒状木质生物质的固定炉排燃烧产生的灰烬中的金的形成，在中试锅炉上进行。生物量样本是从废弃矿区的棕地采集的，避免诱导植物提取。燃料中含有<0.05mg/kg的金，而底部的灰烬，换热器灰后，沉积的灰分,粉煤灰含有1.52毫克/千克，1.99mg/kg,2.64mg/kg,和3.52毫克/千克的黄金，分别。尽管与底灰相比，粉煤灰的含量较低，粉煤灰中黄金的浓度最高，它遵循后热交换器灰和底灰。通过三个阶段的水浸程序富集了金的浓度，酸浸（10%HCl），和碱性浸出（5%NaOH），之后，在从浸出的底灰和沉积的灰中获得的残留物中发现了12.1mg/kg和12.6mg/kg的金，分别。SEM被用来描绘金的形态，其在底灰中表现为纯度高于98%的单个纯颗粒。换热器后灰中存在1-2μm大小的纯金颗粒；同时，粉煤灰中的金主要与钾有关，钠,硫磺,和氧气。这项研究的发现为从生物矿石中回收金铺平了道路，并有助于更好地理解这些二次资源中这种贵金属的形成。
