的开采 聚合 or 矿石 和 subsequent processing of these materials to extract desirable products typically generates a non-valuable fraction called tailings.
当提取富含高浓度物质的矿脉时, 尾矿分数可以很低, but the long history of humans' mining activities has depleted many of the highly concentrated aggregate 和 ore deposits.
今天, 具有高容量的采矿/加工操作, 尤其是在开采珍贵和微量矿物时, the amount of tailings generated can be greater than 90% of the product being mined.
处理尾矿的旧方法
The aggregate 和 mineral industries have historically used the simplest 和 cheapest methods to 管理废浆尾渣. 最古老的方法包括直接倾倒到流中, rivers 和 lakes or using mining surfaces or underground quarries/pits for disposal.
从20年代中期开始th 世纪, these industries have been pressured to eliminate older ways of waste dumping 和 look for safer, 环保高效的技术. The most common method of managing tailings today is stockpiling diluted or concentrated tailings slurries in ponds or impoundment dams.
不像大型水电大坝, tailings ponds are constructed to permanently store the mining solid waste tailings forever. 在21的开始st 世纪，有一个估计 全球3500个尾矿围堵池. Some of the largest containment ponds constructed are over several miles in diameter 和 hundreds of feet deep.
尾矿管理新技术
直到过去十年, little history has been documented on the success 和 failure rate of these tailings dams. Due to several catastrophic large tailings pond failures that have occurred this 世纪, more attention is being given to improving tailings management practices further.
除了数百人的生命损失之外, these major containment failures have destroyed large areas of l和 和 caused major ground 和 waterway pollution. 此外, pressures to improve tailings management are being forced by tighter environmental regulations, 更好地理解高运营成本, the need to reduce waste h和ling costs 和 the increasing need to improve water conservation.
These pressures are forcing industry leaders to evaluate 和 better underst和 their total life cycle cost of tailings management. 基于这些知识, pro-active companies are now justifying the upfront investment in improved tailing management systems. 一些较常见的改良后的尾矿管理系统包括:
地下尾砂回填方式:
- 膏体稠化尾矿泵入地下.
- 将浓缩后的尾矿与水泥混合放置在地下.
地上尾砂放置方式:
- 将糊状的浓缩尾矿泵入池塘或蓄水池.
- 浓缩后的尾矿与水泥混合后干堆.
- 浓缩脱水后的尾矿干堆.
浆料增稠机的溢流.
Placing paste thickened tailings in large tailings containment ponds has been the most common practice of improving tailings management over the past 20-plus years. 粘贴增厚 is similar to other gravity settling thickening technologies but can generate higher tailings concentrations, eliminating up to 70-80% of the volume of material being stored in the tailings pond compared to old non-thickening storage methods.
进一步减小尾矿体积, dewatering technologies have to be employed to remove additional water from thickened tailings slurries before placement in the containment pond.
脱水技术 能否再减少5-10%的尾矿量, 但更重要的是, 足够的水被除去，造成干燥, 可叠起堆放的材料. 脱水后的尾矿仍可含有10- 20%的水分, 但这种材料表现得更像固体, 使在围堵区内干堆尾矿成为可能. 在被安置在隔离区之后, 低水分尾矿非常稳定, 显著降低安全和环境风险.
Common dewatering technologies that have been in existence for decades or even centuries are being evaluated 和 used for tailings dewatering. 这些技术包括:
- 板式压滤机
- 真空带式过滤器
- 带式压滤机
- 离心机
嵌入式/膜板式压滤机技术 has been found to be one of the most efficient methods of dewatering slurry tailings, 回收最大量的水 和 生产最干的蛋糕. Although the capital cost of plate 滤波器按 is higher compared with the other technologies, 运营成本要低得多.
The relative upfront investment 和 ongoing operating cost of the common dewatering technologies are shown below.
干堆尾矿的优点
Industry leaders are finding dry stack tailings can offer many advantages over older, less desirable methods despite the potential for increased upfront 和 ongoing cost.
提高物料储存的结构稳定性
Dry stack tailings storage has been found to greatly improve the structural stability of the material storage, 特别是在地震等级高的地区, near high population centers or near highly sensitive environmental areas.
最大限度地回收循环水
在世界上最干旱的地区, dry stack tailings permit the recovery of the maximum amount of recycled water. The increased recycled water use can help significantly lower highly regulated 和 scarce water sourcing costs.
从压滤机中回收的清水.
回收残余工艺化学品
Dry stack tailings also promote the recovery of residual process chemicals that can be recovered from the recycled water.
最有效的物理存储
尤其是在可用空间有限的地方, 干堆尾矿提供了最有效的物理存储. The dry stack tailings minimize the complexity of permitting 和 minimize the potential of public concerns from nearby communities.
无滴水，脱水的饼从压滤机排出成一堆.
Dry stack tailings management is becoming a more accepted practice due to the recurrent disasters seen with older, non-thickened 和 even more conventional thickened tailings storage facilities. The tragic loss of human life 和 significant environmental 和 physical damage to large tracks of l和 和 communities are accelerating the development of more stable dry stack tailings permitting 和 practices.
Putting economic value to all the potential advantages of dry stack tailings are beginning to justify the higher upfront capital investment cost for efficient dewatering equipment. Industry leaders are beginning to recognize the higher upfront investment 和 operating costs are offset when considering the full life cycle of the mine, 包括 正在进行的尾矿管理 加工设施关闭后的成本.
