One of the industrial wastes, red mud, was assessed as an additive to lime, as a new desulfurization flux for the hot metal in the steelmaking process. Since typical red mud contains some amount of iron oxide, a preliminarily reduced red mud was mainly investigated. Pre-reduction of the red mud and execution of mechanical stirring to the hot metal were effective to enhance desulfurization efficiency (extent and rate of the reaction). However, adding more than 20 pct of red mud in the lime/red mud (pre-reduced) flux did not increase the desulfurization rate. In order to assess the desulfurization efficiency in a more quantitative manner, a “DeS Index” was defined as: $\text{DeS Index}=\log \left[{\left(\frac{{[\text{pct S}]}_{\mathrm{f}}}{{[\text{pct S}]}_0}\right)}^{-1}\left(k\prime \right){\left(\frac{W_{\mathrm{CaO}}}{W_{\mathrm{S}}}\right)}^{-1}\right]$. This takes into account the extent, rate, and cost of the desulfurization simultaneously. With this index, it was found that the presently developed red mud (pre-reduced)/lime mixtures showed almost similar desulfurization efficiency compared with those of commercially used desulfurization fluxes. It was even better than a typical lime/fluorspar mixed flux, which is now prohibited from being used in many companies due to its environmentally harmful character. It is emphasized that the desulfurization efficiency should be assessed under the mechanical stirring in order to be used in the KR type desulfurization process.

其中一种工业废物赤泥被评估为石灰的添加剂，作为炼钢过程中铁水的新脱硫助熔剂。由于典型的赤泥含有一定量的氧化铁，因此主要研究了初步还原的赤泥。赤泥的预还原和对铁水进行机械搅拌对提高脱硫效率（反应的程度和速率）是有效的。然而，在石灰/赤泥（预还原）通量中添加超过 20% 的赤泥并没有提高脱硫率。为了更量化地评估脱硫效率，将“DeS 指数”定义为：$\text{DeS 指数}=\mathrm{日志}\left[{\left(\frac{{[\text{百分比 S}]}_{\mathrm{F}}}{{[\text{百分比 S}]}_0}\right)}^{-1}\left(ķ\text{'}\right){\left(\frac{W_{\mathrm{氧化钙}}}{W_{\mathrm{小号}}}\right)}^{-1}\right]$. 这同时考虑了脱硫的程度、速率和成本。根据该指标，发现目前开发的赤泥（预还原）/石灰混合物与商业脱硫熔剂的脱硫效率几乎相似。它甚至比典型的石灰/萤石混合助焊剂更好，由于其对环境有害的特性，现在许多公司都禁止使用它。强调脱硫效率应在机械搅拌下进行评估，以便用于KR型脱硫工艺。