All aggregate and mining operations with a wet processing plant will produce a waste stream. This waste stream consists of tailings – the process water and fine solids, 在洗涤过程中除去粘土和其他有害物质. 传统上, these tailings are sent to a settling pond or lagoon to separate the solids from the liquid in the waste stream.
然而, 处理池塘既费时又昂贵, 占用宝贵的土地空间和/或掩盖可开采储量. 它们不是尾矿管理的最佳方法, 特别是当机械脱水选项可用时.
机械脱水设备改进 尾矿管理 by separating the solids from the liquid to produce a solids product that is suitable for mechanical handling. 作为额外的奖励, 回收的水可以在洗涤过程中重复使用, reducing freshwater requirements for sites where water is scarce or expensive.
尾矿机械脱水设备类型包括:
- 式离心机
- 带按
- 滤波器按
式离心机
式离心机 separate solids from liquid in a slurry by means of high centrifugal forces to induce sedimentation. The slurry enters the 离心机 via a feed pipe into the inside of a rotating screw conveyor that is tapered at one end. The slurry is then released into a bowl surrounding the screw conveyor that is rotating at a higher speed than the conveyor.
离心机
High G-forces cause the solid particles in the slurry to be flung to the walls of the bowl, 螺旋输送机将它们移向锥形卸料端. The tapered end of the screw allows the solids to dewater as they make their way toward the discharge. The water freely moves to the other end of the machine and discharges via ports.
剖面图显示卧螺离心机如何工作.
卧螺离心机产生一种 适合机械搬运的固体饼状物料 以及可立即重复使用的工艺用水. They discharge a solid material somewhere between that of a 增稠剂 and 压滤机. 式离心机 are fully automated and enclosed for cleaner operation.
从卧螺离心机排出的固体.
带按
带按 feature rollers and belts to dewater material by passing the slurry through four main zones.
第一个区域, 预处理区, 是在哪里添加化学物质使浆液中的颗粒聚集在一起的. 第二个区域, 重力排水带, allows free water to drain from the slurry as it moves along an inclined belt. 第三区, 低压挤压区, 将材料夹在两个多孔带之间, where liquid is squeezed out and the solids are retained between the belts. 第四个区域, 高压挤压区, passes the belts under and over a series of rollers that decrease in diameter.
The result is a dewatered solids material that varies in consistency depending on the solids concentration of the feed.
滤波器按
滤波器按 provide the highest level of mechanical dewatering without the use of chemicals. 它们由许多用滤布覆盖的凹板组成. When the plates are clamped together hydraulically, the recesses form chambers. 浆料被泵入压滤机并填充滤室. The liquid in the slurry passes through the cloth and out filtrate pipes at the bottom of the plates to collect in a trough at the bottom of the 压滤机. 固体被滤布捕获. 当没有更多的浆料可以泵入压滤机, 泵停了, 盘子打开，蛋糕就出来了.
这些固体蛋糕不会滴水, 可堆叠，可通过装载和/或运输设备轻松处理. 根据材料的不同，可以 可能会作为回填土出售 或者池塘衬里. The recovered water is then immediately available for use in the wash plant upstream.
哪种是尾矿管理的最佳选择?
当涉及到尾矿管理, the best equipment for one site may be different than the best equipment for another site. 式离心机, 带按 and 滤波器按 are all suitable choices for pond reduction/elimination, 因此，最佳方案取决于场地的尾矿管理目标.
要考虑的主要问题是要脱水的材料的类型. 式离心机 work best with material that has a larger particle size distribution and is more easily dewatered. 它们也是粘土含量低的材料的理想选择, 而且它们对饲料的变化不那么敏感.
带按 can be used to dewater a variety of different slurries in a wide range of applications, 但它们在不同的饲料条件下表现不佳.
滤波器按 are ideal for dewatering tailings from mineral and aggregate wash plants, mineral concentrates and most underflow slurries coming from a 增稠剂 or clarifier. 然而, the feed percent solids and particle size distribution do have an effect on the overall dewatering efficiency of a 压滤机.
需要考虑的其他事项包括维护和操作, 以及与这些任务相关的成本.
在运营成本方面, 卧螺离心机和压滤机是全自动的, 而带式压力机则需要操作员.
滤波器按 do not require the addition of chemicals to aid in dewatering, while 带按 do. 卧螺离心机可能受益于化学品的使用, 但这取决于被脱水的物质.
式离心机 have higher power requirements than 带按 and 滤波器按, 所以这些单位的电费会更高. 式离心机 also tend to produce more noise than a Belt Press or 压滤机.
在资本成本方面, 带按 are generally less of an upfront investment when compared with 离心机s and 滤波器按. Additionally, 滤波器按 require ancillary equipment, such as a surge (or buffer) tank. Depending on the upstream equipment employed, 带按 and 离心机s may not. 带式压榨机和离心机可以连续运行, 因此不需要调压箱来给机器供油. Slurry is continuously fed into these machines, and they continuously discharge solids. 另一方面，压滤机在批处理过程中运行. A pump feeds the slurry into the machine and stops when the plates are opening to discharge the solid cakes. The feed material needs somewhere to accumulate while the plates are opening, 因此需要一个调压箱.
Maintenance costs are higher with 带按 because maintenance intervals are more frequent than 离心机s and 滤波器按. 皮带压榨机需要经常清洗皮带, and the rollers and bearings are known for requiring frequent replacement, 这意味着更多的停机时间来执行维护.
In terms of footprint, 带按 and 离心机s take up less space than 滤波器按.
当决定 解决方案适合处理您的尾矿, make sure you consider the type of material the equipment will be processing as well as the initial investment and long-term operational and maintenance costs.
