Understanding phosphorus phases in sewage sludge ashes: A wet-process investigation coupled with automated mineralogy analysis

Phosphorus (P) recovery from SSA (sewage sludge ashes) is highly relevant to address future P-shortages. Efficient recycling strategies require an in-depth knowledge of P-phases present. These may be subject to changes during treatment. Treatment was simulated, initial and treated material studied using automated mineralogy. Automated mineralogy, using the MLA system, is an established tool in ore processing evaluation and adapted here to examine P-phases in SSA. Coupling SSA treatment for P-recovery routines with MLA investigations allows for documenting phase compositions during chemical and thermochemical processes. Behaviour of P-phases during treatment and type of SSA govern P-recycling capacity. Findings lend additional insight to the identification of SSA types.Two different P-recovery routines have been investigated. Target phase groups (phosphates) have successfully been digested. Understanding phosphate setup in terms of composition, particle sizes and phase association is vital for an efficient P-extraction from SSA. P-recovery is not straightforward, but rather a series of steps in order to address different P-phase types. SSA is a complex secondary resource, which needs to be understood prior to P-extraction.     

球面上微透镜阵列超精密慢伺服加工精度影响因素的研究

超精密慢伺服车削可加工出高精度的连续和非连续自由曲面,但是在微透镜阵列的加工过程中,不同位置的透镜加工精度也不同,个别子透镜的质量降低可能引起整个功能部件的失效。为了研究曲面上微透镜阵列超精密慢伺服加工精度的影响因素,本文采用实验的方法分析基面几何形状和子透镜位置对球面上微透镜阵列慢伺服车削加工精度的影响,通过在三种不同球径的基面上加工微透镜阵列,并使用Bruker GT-X白光干涉仪测量所加工的基面和微透镜阵列,分析了不同基面上不同位置的子镜表面粗糙度和形状精度的变化趋势。实验结果表明,同一基面上不同位置的子透镜,慢伺服车削加工表面微观形貌不同,表面粗糙度和形状精度也不同;基面的几何形状也会影响子镜的加工精度,当基面球径从50 mm增大至150 mm时,外圈子镜的表面粗糙度从75.78 nm(Ra)变小为69.08 nm(Ra)。在超精密慢伺服加工微透镜阵列过程中,必须考虑基面几何形状和子透镜位置两个因素对加工精度的影响,这将有助于提高微透镜阵列加工精度的一致性并保证微透镜阵列功能的有效性。     

Using mineralogical characterisation and process modelling to simulate the gravity recovery of ferrochrome fines

The recovery of ferrochrome (FeCr) alloy from fine (<600 μm) ferrochrome slag typically involves the use of gravity concentration, amongst other physical separation techniques. This study demonstrates the value of utilising mineralogical methods both to determine alloy composition and liberation and to assist in setting up partition surface models for a shaking table. A Mineral Liberation Analyser (MLA) was used to measure size, density, shape and liberation data of each alloy and mineral in a set of shaking table products. The amount of detailed data gathered by the MLA was sufficient to generate particle tracking analysis (PTA) data in order to simulate the recovery of alloy and mineral phases. Two flowsheet configurations were evaluated to ascertain the possibility of producing a high grade product (>97.5% metal content) comparing shaking table and Reflux Classifier performance. The results of this study show that an approach of using particle characterisation by MLA, coupled with surface partition modelling, may be a useful technique to model gravity separation of fine particles, especially where both valuable and gangue phases contain common elements in their composition.     

The effect of microwave pretreatment on impact breakage of copper ore

It has been shown that very short exposures to a high level of microwave power lead to reductions in ore strength. In this paper, the influence of modulated microwave power on copper ore breakage has been investigated. This approach to power delivery is applied to ascertain whether the strength of porphyry copper ore can be reduced with lower average modulated power levels than using continuous power. Changes in resistance to breakage of the treated and untreated ore were quantified by comparative drop weight tests. Mineralogical investigation for the ore was carried out with the Mineral Liberation Analyser (MLA) for surface identification of minerals and X-ray tomography for volumetric analysis. The comparative drop weight tests showed that material treated for 5 s at 5 kW of modulated power was weaker than untreated material. However, for this particular low grade ore, the degree of breakage which was achieved could be achieved with substantially less mechanical energy. It is possible that by using much higher level of microwave power, better liberation might be achieved than using conventional methods.     

白云鄂博西矿工艺矿物学及稀土、萤石浮选试验研究

采用矿物解离分析仪和化学等分析测试手段,在磨矿细度为-0.074mm占92.27%的条件下,对白云鄂博西矿的矿物组成、嵌布特性和粒度分布等方面进行研究。根据矿石的矿物学特征和工业选矿流程的可行性,对原则流程进行了制定并进行了条件优化试验。在此基础上,采用新型稀土捕收剂CMS-1和抑制剂CAM-1,通过稀土浮选开路试验得到REO品位为10.17%,回收率为86.15%的稀土粗精矿。采用新型萤石捕收剂CMK-2和抑制剂CMP-1和CMP-2,通过实验室小型闭路试验,得到CaF₂品位90.80%、回收率33.00%的萤石精矿,为选别同种类型矿石提供理论依据。     

Enhancing mineral liberation of a Canadian rare earth ore with microwave pretreatment

Liberation, as an attribute of mineralogy characteristic, whose impacts on finely disseminated Canadian rare earth ore was studied with microwave pretreatment. Samples of a light rare earth ore along with mostly ankerite and biotite as dominant gangue minerals as well as bastnaesite, strontianite and goethite as dominated minerals were exposed to further comminution by ball mill and microwave pretreatment fragmentation. Mineralogical characteristics were analyzed by using a mineral liberation analyzer (MLA). The results indicated that tight association mutually penetrates among dominated minerals in the range size of ?300 + 212 μm and ?212 + 150 μm and gangue minerals in the form of adjacent type, fine vein type, shell type and packing type. Temperature in the ore samples pre-treated by microwave can rapidly rise to 250 °C with microwave power of 0–1.5 kW and microwave time of 0–2 min. Applying the microwave pretreatment merely reduces the hardness of the ore causing the fracture of rare earth ore, but this does not transform or change the original mineralogy characteristics of the ore samples. On the basis of above study, the liberation value of bastnaesite, strontianite and goethite with microwave pretreatment is greater than with conventional comminution when the liberation class is above 75%. The distribution of particle size of rare earth ore samples is better with microwave pretreatment than with conventional comminution for particle size of 7.4 × 10^?5 m. With microwave pretreatment, the theoretical grade–recovery of bastnaesite, strontianite and goethite in the rare earth ore attains better results than with conventional comminution at a given grade.     

MLA技术在某铜钼矿选矿工艺研究中的应用

MLA是目前世界上最先进的工艺矿物学参数自动定量分析测试系统之一。目前国内MLA技术主要用于指导选矿工艺研究,以要进行选矿加工的矿石为研究对象,为选矿流程提供矿物组成、含量、目标矿物嵌布粒度、磨矿产品解离度、伴生元素赋存状态等信息,指导确定选矿工艺,提高选矿试验研究效率。本研究采用MLA技术指导某铜钼矿选矿工艺研究。根据MLA工艺矿物学研究结果确定选矿工艺和药剂制度,通过条件试验确定详细的工艺参数和各药剂用量,最终在原矿铜品位0.63%、钼品位0.022%的条件下,得到铜品位24.82%,铜回收率91.90%,钼品位35.15%,钼回收率57.56%的选别指标。与现场生产指标相比,铜回收率接近,钼回收率提高12%。     

MLA在广东斑岩型锡石矿嵌布特征及赋存状态研究中的应用

利用矿物自动分析系统(MLA)和X射线荧光光谱仪、原子吸收分光光度计等对广东某斑岩型锡矿小于2 mm的原矿进行工艺矿物学研究，考察矿物组成、嵌布粒度、连生及包裹关系。结果表明，锡石主要呈细粒浸染状嵌布于脉石矿物中，嵌布粒度细微，最大粒度约为0.250 mm，最小为0.001 mm，主要集中在0.020?0.090 mm之间，单体解离度仅为9.98%，连生体主要与石英、黄玉连生。约93%的锡石(硬度6.5)被石英(硬度7)、黄玉(硬度8)包裹或与之连生，属难磨难选矿石，原矿伴有少量钼、铋、钨、铜等有价元素。选矿原则流程可确定为优先浮选回收硫化矿(钼、铋、铜、钨)，窄级颗粒分别(或依次)重选回收锡石。     

内蒙古某斑岩型铜钼矿石混合浮选试验研究

针对内蒙古某斑岩型铜钼矿石由于性质发生变化,导致的铜钼混合浮选流程泡沫黏度大、浮选指标不理想等问题,进行了铜钼混合浮选工艺研究。结果表明:在磨矿细度-0.074 mm占60%的条件下,以CG705作为调整剂,采用一次粗选、三次精选、三次扫选、中矿顺序返回的闭路流程,可获得铜品位19.250%、钼品位1.360%,铜回收率84.24%、钼回收率51.13%的混合精矿,较好地解决了该矿石混合浮选中存在的难题。     

黑龙江省某含钒超贫磁铁矿矿石性质及选矿试验研究

针对黑龙江省某含钒超贫磁铁矿，对原矿化学成分、铁物相和矿石结构构造进行分析，再采用MLA、扫描电镜、电子探针等先进手段对矿物组成、主要矿物的嵌布特征进行详细研究，发现矿石中全铁含量12.40%（磁性铁占67.34%），V2O5含量0.186%，矿石中磁铁矿和钛铁矿、磁黄铁矿紧密共生，对选矿指标产生影响。通过选矿试验研究，在磁场强度条件试验和不同磨矿细度磁选工艺试验研究基础上，对铁精矿产品进行化学分析和有用成分回收情况分析，推荐最佳选矿工艺流程及指标：原矿在一次磨矿细度-200目含量95%的条件下，经过两次磁选，可获得全铁含量64.18%、回收率61.25%（磁性铁含量63.91%、回收率90.58%）的铁精矿，铁精矿中V2O5得到富集，含量为0.96%，回收率为61.08%。研究结果为该矿开发利用提供参考。