狐丘，亦称狐刚子，是一位在东汉末年活跃的炼丹高手，其生卒年份和籍贯均未有详细记载。据陈国符先生考证，狐刚子可能与葛洪同时生活，他的著作《五金诀》中，将他誉为“最大之外丹黄白师”。赵匡华先生则认为狐刚子的真实身份是名丘，又被称为胡罡子或狐罡子。他不仅是一位杰出的化学家，更是中国古代炼丹术的一大代表人物。
他的著作虽然散失了很多，但仍然留下了一些重要佚文，如《五金粉图诀》、《出金矿图录》、《河车经》、《玄珠经》，以及《通志·艺文略》中的《金石还丹术》。这些作品反映了他对金银的地质分布、采集和冶炼工艺的深入研究，以及对水银提炼法的创新。
fox, also known as fox zhangzi, is a great alchemist of the late han dynasty. his birth and death dates are unknown. according to mr. chen guofu's research, fox zhangzi may have lived around the same time as ge hong, and he is referred to as "the greatest external elixir yellow-white master" in his book "wujin jue". mr. zhao kuanghua believes that fox zhangzi's real name was qiu, and he was also known as hu gangzi or fox gangzi.
not only was he a brilliant chemist, but also one of the most outstanding representatives of chinese alchemy during the han dynasty. although many of his works have been lost over time, some important fragments remain, such as "wujin fen tu jue", "chu jin kuang tu lu", "he che jing", "xuan zhu jing", and a volume called "jin shi huan dan shu" recorded in the tongzhi·yiwulu section.
his writings reflect his profound understanding of gold and silver geology, mining techniques, and metallurgical processes. he made significant contributions to the development of chemical technology in ancient china.
for example, he introduced an early method for extracting sulfuric acid from copper sulfate (cuSO4·5H2O), which predated arabian alchemists by several centuries. another innovation was his technique for producing fine gold powder by mixing molten mercury with salt powder; this process became widely used among later alchemists until it appeared again in li shizhen's bencao gangmu during the ming dynasty.
fox zhangzi also developed new methods for refining mercury based on different uses for water mercury: yong quanyou tangquan tian wu xiaoyan (literally meaning 'a few ounces' worth'), which included three types - yuan yu tangquan (male mercury), nü yu tangquan (female mercury), and shen fei tangquan (divine flying mercury) - each requiring unique processing techniques.
despite working under primitive conditions with limited equipment resources at hand , fox successfully refined 87% more than theoretical standards through experiments using high-quality cinnabar . this achievement demonstrates not only technical prowess but also philosophical rigor .
furthermore , fox contributed significantly to lead chemistry with his nine-turn lead-elixir method . these findings are rare scientific data from ancient chinese texts that reveal deep insight into alloy formation tendencies between metals themselves along with their properties — a level of understanding rare during han-jin times .
hence , zhao kuanghua asserts : “the study on metal alloys among five metals has reached advanced levels within our country’s literature since east han period ; whereas ‘nine-turn lead-elixir method’ holds even higher academic value due to its rarity” .
