尾矿. 拒绝. 吐唾沫. Even to those not involved with the mining industry, it is obvious by the very words — rejects, slimes — that we probably won’t see red carpet stars adorned with, majestic high rises built from, or energy production fueled by tailings or any of its other worthlessness-invoking monikers. We mine because the materials we extract have value and demand. As concentration and refinement processes reduce these values to ever smaller volumes, we discard the barren or low-value materials and, 人性使然, focus more on the values: the gold, 洁净煤, the competent aggregate.
矿业公司过去对尾矿“管理不善”的做法至今仍困扰着该行业的每个部门，这并不是什么启示. What most people don’t get, 虽然, is that we have by and large been very cognizant that to remain in business, 打开新属性, to sustain modern living, 我们处理或计划处理尾矿的方式与矿床本身一样，对合资企业的成功至关重要.
The best way to deal with tailings is to answer the question “What do you envision as the long-term solution?” This will often depend on the characteristics of the tails. If the tailings are comprised of relatively coarse particles (+38 microns), 那么答案可能很简单，只要把它们抽到旋风中进行恢复和大坝建设，将良好的旋风溢流截留在大坝后面.
这种方法有, 几十年来, been employed to both collect/store tailings as well as clarify water for reuse in the process plant. 还有什么能比挖一个洞或建一个水坝，为我们的活动产生的废物创造一个空间更便宜呢? 有 certainly costs associated with this plan. Two of the most frequent laments are: “We don’t have enough screens,” and “Our ponds are running out of space.” Dredging a pond to create more room for incoming tails may not be an everyday operational cost, 但当时机成熟时, 吹笛手想要他的那份. Of course, an additional pond could be opened, but space and/or permitting might not be possible. 另外, 有可能掩盖储备，你可能需要得到一天和损失的过程水由于蒸发或渗透.
Besides the costs associated with the pond solution, there are also risks. 社会风险包括在维护池塘或建造更高的蓄水结构时将人安置在水上或水附近. 蓄水失败对社会和环境造成的严重影响是真实存在的，在任何风险分析中都应予以重视. It's our industry’s obligation to reduce these risks as much as possible.
增稠剂
If the tailings are finer (-38 microns) and if ponds are still the desired method for storage, 在把整条鱼送到池塘之前，考虑用一个增稠器来准备鱼尾可能是值得的. 增稠器的好处是减少了流向池塘的总体积，并立即将大部分工艺用水返回到工厂. In processing operations today, there are three basic styles of thickeners:
- 高速率
- 高密度
- 粘贴
Each of these thickeners share a similar operation as far as feeding and collection of the settled solids. Feed enters the unit via a feedwell, 哪种设计能提供最佳的混合和停留时间，使悬浮固体与絮凝剂接触并形成絮凝体. The flocculated suspension then flows out of the feedwell and is dispersed across the area of the tank. 絮凝固体下降，而澄清水上升超过外围堰收集在工艺水箱. The flocculated solids collect in the cone section of the thickener. To gather this mud and bring it to a central discharge area, these tanks use slowly rotating rake mechanisms. It should be noted here that lower yield stress muds, such as those produced in a high rate thickener, require less torque to move these rakes through the mud.
再一次。, 选择适合您需求的稠化剂在很大程度上取决于所产生的泥浆的下游计划. As we progress from high rate to the paste thickener, the underflow solids concentration possible will increase. Here is where the concept of yield stress comes in to play. 在流变学, the yield stress is the minimum amount of shear stress required to initiate and sustain flow. The higher the underflow solids concentration, then the higher the yield stress. 矿山规划人员可以最好地确定增稠过程，从系统的末端开始并向后工作. Answers to the questions regarding how the tails are to be stored, 放置, 运输, and produced are key to honing in on the thickener design.
高速率增稠剂
高速率 thickeners are used to provide lower yield stress muds. 仅在重力条件下，这些泥浆就可以很容易地泵出，并在相对较大的区域内流出. 迄今为止，它们是当今工业中使用最多的浓缩机，为回收水和将浓缩的尾矿输送到蓄水池提供了一种相对廉价的方法. Water and solids will further segregate in the impoundment area, which will need to be dealt with either by return to the process plant, evaporation or discharge.
The high rate thickener, whether it sits flat on the ground or is elevated, collects mud in a shallow cone, generally between 9 and 12 degrees. 这些装置的侧壁是三种类型的增稠器中最低的，并且提供了最短的停留时间来压缩泥浆.
高密度增稠剂
高密度 thickeners are used when you need a bit higher solids concentration or mud yield stress. The thickeners are sized to give longer mud residence times to allow for further compaction, and the rake drives and supporting structures must be designed to deal with a higher yield stress mud.
高速率和高密度增稠剂通常都配备耙提升机构，以便在高扭矩条件下将耙从泥浆中拉出. The torque is constantly monitored. As the torque decreases due to higher pump-out rates or reduced inflow of mud, then the rakes are indexed back down to their lowest position.
粘贴增稠剂
膏体增稠剂为作业者提供了仅通过重力沉降即可产生最高底流浓度和屈服应力泥浆的能力. These tanks typically have aspect ratios (height:diameter) of 1:1 to 1.5:1 and steep underflow cones ranging from 25 to 60 degrees. The principal design consideration for a paste thickener is the mud residence time. 浆糊是一个术语，用来描述一种泥浆，其中很少或没有进一步的自由水从固体中分离出来. To further enhance the formation of the paste, the rakes are often equipped with vertical rods or angles that protrude upward in the tank. 这些尖桩用于在泥浆中凿出通道，以便在泥浆压实时将困住的水从泥浆中释放出来.
Due to the high yield stress of the muds, paste thickeners must often be equipped with special pumping arrangements for mud removal and transport. Positive displacement pumps such as piston or piston diaphragm pumps are often used. However, many mineral based muds will exhibit a viscosity characteristic known as rheomalaxis. This is the irreversible thinning of a slurry with time as it is subjected to shear. 在这种情况下, the underflow cone of a high density or paste thickener may consist of two process pumps. One pump has the duty of withdrawing sludge and pumping it back into the cone via a shear loop. This serves to reduce the yield stress of the mud. 第二泵用于将屈服应力较低的泥浆从稠化器中移出，并将其输送到放置区域. 由于可以使用离心泵，并且放置可以更好地利用可用于物料流动的区域，流变体泥浆可以使处理膏体的成本更低. 另外, if the placement of the low water content mud is made in shallow lifts, drying time for the mud can be greatly reduced.
So why would someone want to go through the trouble of creating these higher yield stress muds? 有, 当然, several reasons why this would be considered, including higher recovery of water and usefulness in mine backfill, but a reason that has great benefit is the stability of the mud once in place. Higher yield stress muds pose lower risk of impoundment failure. The benefits of this are well understood.
Success of your thickening system really requires that a sound effort is made to understand the tailings. This is done by a number of suppliers through detailed settling and viscosity analysis of the muds. 在过去的15年里，连续沉降试验的方法已经被开发出来，并且已经被证明比静态试验提供了一组更好的施胶和选择增稠剂的数据.
If we progress on in the thickening continuum, where do we go after paste thickeners? 我们现在进入了一个区域，除了重力之外，必须引入其他力来产生更高的固体浓度. This is the realm of filters and centrifuges. Most recently, the coal and aggregate industries have discovered recessed plate presses, an 旧的技术 used by the wine and olive oil industries but redesigned for successful use by mining operations. Of particular interest with this technology is the ability to prepare tailings, without additional chemicals, that allow dry stacking and total elimination of impoundments to restrict flow of muds and water.
凹式压板机
At its most basic level, the filtration process of a filter press consists of covering two plates with filter media, applying enough force to create a seal between the two filter plates, 然后使用进料泵提供必要的压力，将浆液泵入两个密封板之间形成的腔中. 滤布防止固体从板中逸出，同时允许滤液通过过滤介质中的开口. Once the chamber is packed full of solids, 给水泵停止工作, the pressure sealing the plates is released and the filter plates are pulled apart from each other, allowing the dewatered cakes to discharge via gravity.
It is a common misconception that these presses squeeze the plates in order to dewater the cakes. In actuality, there is no movement of the press during the formation of the filter cakes. Plates connect together to form a seal, and the feed pump supplies the necessary pressure to dewater the fine solids. 在操作过程中，压力机的唯一运动通常是打开压力机以排出饼，关闭压力机以开始另一个循环.
压滤机的简单性和有限的运动使它们具有高水平的自动化和可靠性. The ability to select cycle times, 蛋糕厚度, 进料压力和板型是什么允许压滤机实现比许多其他竞争技术更干燥的排放.
The recessed plate press operation is a batch process and when asked, “What is the capacity of the press?” we must answer that the capacity is strictly a function of the cycle time. Each press comes with a finite volume to form cakes. Shorter cycle times (the time it takes to go from start to start) are promoted by:
- Optimizing 蛋糕厚度 – Thinner cakes can form quicker than thicker ones.
- Higher permeability of solids – The easier it is for water to pass through the cake, the quicker the filtration stage.
- Optimum cake moistures – If 18% moisture is achievable in 40 minutes, is 20% after perhaps 30 minutes acceptable?
- Higher feed solids concentrations – The less water to push through the cake, the more rapid cake formation.
- 更快的开启和关闭-卸饼和重置下一个填充阶段的压力机可以在每小时的基础上发挥很大的作用.
再一次, testing your material is always a good place to start when looking at a recessed plate press. Most manufacturers will have facilities for 内部测试 来确定, 非常准确地, filtration times and moistures as a function of feed solids concentration and cake width.
Filter presses are frequently categorized into two main styles: overhead beam and side beam. Each have their own advantages and disadvantages.
头顶的梁
- The filter plates hang from overhead beams.
- No parts on the sides of the press, providing unobstructed access to change filter cloths on the press without plate removal.
- Much wider plate openings often exceeding 3' (0 .9 m ) between the plates. 这创造了更多的运动，以帮助饼释放，同时也允许更容易地进行洗布和检查.
- Dynamic loads are typically isolated from the beams of the press using tension shafts in various configurations.
侧梁
- The filter plates are supported by beams running along the side of the press.
- Easier to implement shaking systems for applications requiring shaking systems.
- 较低的前期成本.
- Less access to plates for cloth washing and inspection. 自动洗涤系统应该更多地考虑与侧梁式压力机，由于有限的板访问.
