Protocol to Quantify the Reactivity of Carbonate Limestone for Horticultural Substrates
Protocol to Quantify the Reactivity of Carbonate Limestone for Horticultural Substrates
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量化园艺基质碳酸盐石灰石反应性的协议
DOI：
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发表时间：
2007
期刊：
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通讯作者：
William R. Argo
中科院分区：
文献类型：
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作者：
Jinsheng Huang;P. Fisher;William R. Argo
摘要 目前比较用于校正园艺基质 pH 值的不同石灰石的反应性的方法是基于批量试验，其中将石灰石掺入基质中，并随着时间的推移（通常长达 28 天）测量 pH 值。目的是测试实验室方法，以对各种石灰石来源的反应性进行快速分析测试。向石灰样品中添加 4M 盐酸 (HCl)，并测量随时间推移释放到滴定管中的二氧化碳 (CO2) 的体积。对试剂级碳酸钙 (CaCO3) 和两种市售的粉状白云质石灰石进行了测试。此外，还评估了来自每个石灰石样品的六个粒径部分的反应速率和相应的 pH 响应。加酸后不到 1 分钟，100% 的 CaCO3 发生反应，而 50% 的石灰石样品分别需要 3.9 和 11.5 分钟发生反应，90% 的中和分别需要 14 和 52 分钟。反应速率随粒径减小而增大；然而，对于大于 150 µm（> 100 美国目）的颗粒，观察到类似的反应速率。当每升泥炭基质掺入 6 克每种石灰时，90% 反应的时间与 pH 值响应呈负相关。可以建立石灰反应指数，例如基于50%或90%反应所需的时间，从而提供不同石灰石来源的快速筛选。
Abstract The current method for comparing the reactivity of different limestones used to correct pH in horticultural substrates is based on batch trials, where the limestones are incorporated into the substrate and the pH is measured over time (typically up to 28 days). The objective was to test a laboratory approach to provide a rapid analytical test on reactivity of various limestone sources. To a lime sample, 4M hydrochloric acid (HCl) was added, and the volume of carbon dioxide (CO2) released into a burette was measured over time. Reagent‐grade calcium carbonate (CaCO3) and two commercially available pulverized dolomitic limestones were tested. In addition, six particle‐size fractions derived from each of the limestone samples were also evaluated for reaction rate and the corresponding pH responses. In less than 1 min after acid addition, 100% of CaCO3 reacted, whereas it took 3.9 and 11.5 min, respectively, for 50% of the limestone samples to react, and 14 and 52 min, respectively, for 90% neutralization. Reaction rate increased as the particle size decreased; however, a similar reaction rate was observed for the particle sizes larger than 150 µm (>100 U.S. mesh). Time to 90% reaction was negatively correlated with pH response when 6 g of each lime was incorporated per L of peat substrate. It may be possible to establish a lime reactivity index, for example based on the time required for 50% or 90% reaction, and thereby provide a rapid screening of different limestone sources.