低品位残坡积钛砂矿选矿工艺研究

国内某储量丰富的低品位残坡积钛砂矿,含TiO_2、Fe分别为4.73%、16.24%,其中可回收的钛和铁主要以钛铁矿和钒钛磁铁矿的形式存在。针对该矿的特点,进行了详细的选矿工艺研究,确定"原矿擦洗-强磁粗选-弱磁选铁-重选精选"的工艺流程,获得了品位为45.97%、回收率为27.27%的钛精矿,以及品位TiO_2为37.73%、回收率为3.74%的钛中矿,同时还获得了品位为55.68%的铁精矿,达到综合利用利用的目的。     

马拉维湖滨型钛铁砂矿选冶分离试验研究

对马拉维湖滨砂矿进行了工艺矿物学和选冶分离试验研究。结果表明,通过磁选、摇床重选、电选及还原焙烧等选冶联合工艺,获得了TiO₂品位49.85%、全流程回收率61.03%的合格钛精矿和ZrO₂品位大于63%、全流程回收率52.51%的锆精矿,同时综合回收了TFe品位分别为65.80%和48.74%的2种铁精矿。     

浅论砂金矿床形成的地质条件

叙述了外生条件下砂金的地球化学性质,搬运介质及动力条件对砂金矿形成的意义,构造条件与砂金矿床形成的关系,地貌条件对砂金矿床形成之影响,砂金的补给源条件,砂金矿保存条件。研究砂金矿床的形成规律及不同砂金矿床的成矿地质条件,对进一步寻找有价值的工业砂金矿体,扩大储量,具有十分重要的经济意义。同时砂金矿床的发现常可作为原生金矿的指示标志,故研究其成矿地质特征,又有重要的地质意义。     

Fecal indicator bacteria are abundant in wet sand at freshwater beaches

Potential fecal contamination of sand in the wave-washed zone of public bathing beaches is overlooked in beach monitoring programs. Activity in this zone can bring pathogens to the sand surface or into the water, presenting a health risk to sensitive populations. On a unit weight basis (colony forming units per 100g), the mean summer abundance of the fecal indicator bacteria enterococci and Escherichia coli was 3-38 times higher in the top 20 cm of wet-sand cores than in the water column at six freshwater bathing beaches. E. coli were 4 times more abundant than enterococci in water but counts were similar in the sand. A correlation (r=0.60) existed between E. coli counts in the water and in the top 5 cm of sand only, whereas no relationship existed between enterococci abundance in water and sand. In general, enterococci were most numerous in the 5-10 cm sand stratum and E. coli in the 0-5 cm stratum. These preliminary data show that wet freshwater beach sand is a reservoir of fecal indicator bacteria. Enteric pathogens may also be present in beach sand.     

印尼Lokasi海滨砂矿工艺矿物学研究

我国钒钛磁铁矿资源主要分布在四川攀枝花,河北承德等地区,海滨砂矿类型矿床较少。为了查明该类型的钒钛磁铁矿矿砂可选性,为其开发利用提供理论依据。通过化学多元素分析,电子探针分析,能谱分析等方法对印尼Lokasi海滨砂矿工艺矿物学特征进行研究。原矿砂铁品位为26.03%,伴生TiO2和V2O5含量分别为5.66%和0.22%,达到了伴生组分综合利用工业要求;钛磁（赤）铁矿与钛铁矿的含量分别为25.59%,3.87%。矿石矿物粒度范围较窄,分布集中。钛磁铁矿原矿单体解离度达90%,单体和大于3/4连生体之和达99%,磨矿成本极小。该区的钛磁铁矿和钛铁矿都是成分不均一的固溶体矿物,因此钛铁矿中Ti含量要低于理论值,目前不能从Lokasi海滨砂矿中选出独立的高品位钛精矿。      

砂金选矿工艺检测探讨

我国砂金矿山迄今尚未建立一套规范的工艺检测方法,安康金矿集多年生产实践,总结出了简便可行符合生产规律的取样检测及回收率计算方法,有效指导了生产,在砂金生产上有一定推广价值.     

Beachgoers’ beliefs and behaviours in relation to beach flags and rip currents

Background

Coastal drownings claim on average 82 people per year in Australia. Beach flags are a primary safety strategy used on beaches. They are located away from rip currents, which are the main beach hazard affecting swimmers. Little is known about the behavioural and motivational factors associated with people choosing where to swim in relation to flags and rips.

Aims

To assess the beliefs and behaviours of beachgoers in relation to beach flags and rip currents.

Methods

Beachgoers at beaches in NSW were interviewed about their swimming beliefs and behaviours. They were asked to indicate on pictures depicting beach scenarios involving beach flags and fixed rip currents, where they would and would not swim. Logistic regression analysis was undertaken to determine predictors of correct and incorrect swimming behaviour.

Results

Beachgoers who are aged from 30 to 49 years (OR 0.34, 95% CI 0.16, 0.74, p = 0.006) are less likely to choose to swim between the flags than other swimmers. In addition, beachgoers who are at the beach with children are significantly more likely to choose to swim between the flags (OR 2.74, 95% CI 1.39, 5.40, p = 0.004). Beachgoers with basic knowledge about rip currents are significantly more likely to swim away from the rip (OR 11.59, 95% CI 5.89, 22.81, p < 0.001).

Discussion and conclusions

Ocean swimmers aged from 30 to 49 years may choose to swim outside the flags, though they may not necessarily be swimming in the rip. Swimming outside of the flags may be linked with experience. The flags appear to be attractive to parents and carers of children. Whilst the flags indicate a relatively safe area of the beach, it is still vitally important for parents and carers to supervise children in this area. Basic rip current knowledge is an essential component in developing national interventions aimed at reducing coastal drowning. Beachgoers clearly need to know what a rip looks like in order to actively avoid swimming in it.     

莫桑比克某海滨砂矿重选-磁选工艺试验研究

莫桑比克某海滨砂矿TiO₂品位3.33%, 为开发利用该资源, 开展了重选-磁选工艺试验研究。原矿搅拌调浆后, 经过螺旋溜槽一次粗选和一次精选、重选精矿弱磁选、弱磁尾矿强磁选工艺处理, 可获得TiO₂品位39.15%、TiO₂回收率74.63%的钛精矿。研究成果为该资源的后续处理提供了数据支撑和技术支持。     

Rescues conducted by surfers on Australian beaches

This study describes the demographics, occurrence, location, primary hazards and outcomes involved in rescues performed by surfers on Australian beaches. Conservative estimates suggest that the number of rescues conducted by Australian surfers each year is on par with the number conducted by volunteer surf lifesavers. Surfers perform a considerable number of serious rescues in both lifesaver/lifeguard patrolled (45%) and unpatrolled (53%) beach locations. Rip currents represent the major physical hazard leading to rescue (75%) and the dominant emotional response of people rescued is one of panic (85%). Most surfer rescue events occur during conditions of moderate waves and sunny, fine weather with the highest proportion of rescues occurring on quiet beaches with few people around (26%). Swimming is the activity associated with most rescue events (63%), followed by board riding (25%). Males aged 18–29 represent the largest demographic of people rescued. Surfers with prior water-safety training are more likely to perform a higher number of rescues, however ability to perform rescues is not associated with formal training, but rather number of years’ experience surfing. Seventy-eight percent of surfers were happy to help, while 28% expressed feelings of annoyance or inconvenience, generally towards unwary swimmers. Results of this research suggest that 63% of surfers feel they have saved a life. This value may be enhanced through improved training of surfers in basic water safety rescue techniques.     

A multi-beach study of Staphylococcus aureus, MRSA, and enterococci in seawater and beach sand

Incidences of Staphylococcus aureus and methicillin resistant S. aureus (MRSA) have risen worldwide prompting a need to better understand routes of human exposure and whether standard bacterial water quality monitoring practices adequately account for this potential threat. Beach water and sand samples were analyzed during summer months for S. aureus, enterococci, and MRSA at three southern California beaches (Avalon, Doheny, Malibu Surfrider). S. aureus frequently was detected in samples of seawater (59%, n = 328) and beach sand (53%, n = 358). MRSA sometimes was detected in seawater (1.6%, n = 366) and sand (2.7%, n = 366) at relatively low concentrations. Site specific differences were observed, with Avalon Beach presenting the highest concentrations of S. aureus and Malibu Surfrider the lowest in both seawater and sand. S. aureus concentrations in seawater and sand were correlated to each other and to a variety of other parameters. Multiple linear regression on the combined beach data indicated that significant explanatory variables for S. aureus in seawater were S. aureus in sand, water temperature, enterococci in seawater, and the number of swimmers. In sand, S. aureus concentrations were related to S. aureus in seawater, water temperature, enterococci in seawater, and inversely to surf height classification. Only the correlation to water temperature held for individually analyzed beaches and for S. aureus concentrations in both seawater and sand. To provide context for these results, the prevalence of S. aureus in sand was compared to published fomite studies, and results suggested that beach prevalence was similar to that in homes.