Abstract

A new eco-friendly process to comprehensively utilize boron-concentrate is proposed in this paper. In this process, Iron-concentrate, silicon dioxide, magnesium oxide, and boric acid could be produced from boron-concentrate. The highlight of this process was minimal waste discharge during the whole process. Iron removal was a key step to ensure the quality of boric acid and magnesium oxide. The introduced goethite precipitation method could remove iron to a very low level. With the addition of 3 cm³ H₂O₂ (5 vol. %) as an oxidizing agent, more than 99% of iron was removed from the leaching liquor. After the removal of iron, the resulting liquor was used to prepare magnesium precipitate. And the optimal preparation conditions were: the temperature of 30 °C and precipitation time of 60 min, ammonium- magnesium ratio of 1.5, the magnesium ion concentration of 34.8 g·L⁻¹. Under those conditions, the magnesium precipitation efficiency was up to 98.5%. Magnesium oxide was obtained by roasting magnesium precipitate at 550 °C for 2 h. Then the mixed crystals of ammonium sulfate and boric acid were obtained by evaporating the liquor after iron removing and magnesium precipitating. Boric acid was separated from ammonium sulfate by dissolving the mixed crystals in ethanol solution.

Graphical Abstract

中文翻译：

---

湿法冶炼硼精矿的综合利用

摘要

本文提出了一种综合利用硼精矿的环保新工艺。在此过程中，可以从浓缩硼中生产铁精矿，二氧化硅，氧化镁和硼酸。该过程的重点是在整个过程中将废物排放降至最低。除铁是确保硼酸和氧化镁质量的关键步骤。引入的针铁矿沉淀法可以将铁去除到非常低的水平。加上3 cm ³ H ₂ O ₂（5体积％）作为氧化剂，从浸出液中除去了超过99％的铁。除去铁后，将所得液体用于制备镁沉淀物。最佳制备条件为：温度30°C，沉淀时间60 min，铵镁比1.5，镁离子浓度34.8 g·L ^-1。在这些条件下，镁的沉淀效率高达98.5％。通过在550°C下焙烧镁沉淀2小时获得氧化镁。然后，通过在除去铁和镁沉淀后蒸发液体，得到硫酸铵和硼酸的混合晶体。通过将混合的晶体溶解在乙醇溶液中，将硼酸与硫酸铵分离。

图形概要