Upgrading Phosphogypsum for Uses as Construction Materials

Over 70% of the world’s phosphate rock product is consumed by the “wet” process for production of phosphoric acid, which is mainly used for fertilizer manufacturing. In this process, roughly 5 tons of phosphogypsum (PG) are generated per ton of P2O5 produced. On that basis, at least 150 million tons of PG are being added annually to the world stockpile of billions of tons. Although the Florida style stacking with lining is the state-of- art PG disposal practice and may stay dominant in the phosphate industry for years to come, this practice is neither cost effective nor environmentally sound. The phosphate companies, particularly those in China, are under great pressure to find uses for PG quickly. Use of PG as construction materials could ease the problem significantly. However, due to its high content of P and other gangue materials such as fluorides and silica, this line of PG use is severely limited. Under this research program, a combination of gravity separation with flotation produced an upgraded PG acceptable for many construction uses. The results summarized in Table 1 indicates this. Please click Additional Files below to see the full abstract

Separation of Dolomite from Phosphate at Low Cost and Reduced Environmental Impact

Magnesium (MgO) in phosphate rock causes numerous problems in the phosphoric acid manufacturing process, including reducing filtration capacity, increasing sulfuric acid consumption, and making it difficult to meet product grade. MgO-containing minerals are fully dissolved and usually coexist in phosphoric acid by acid hydrolysis reaction to form Mg(H2PO4)2. This makes it extremely difficult to separate the dissolved Mg from phosphoric acid. Therefore, it makes both economic and technological sense to remove dolomite from phosphate prior to acidulation. Except for limited use of heavy media gravity separation, flotation is the main technology currently practiced for separation of dolomite from phosphate. Because fine grinding is required to liberate dolomite for flotation separation, use of mechanical flotation cells is very expensive due to energy cost, long flotation time and high reagent use. Recent development efforts have resulted in industry acceptance of an innovative flotation device, the packed flotation column (PFC), thus realizing its six (6) main advantages: low energy use long separation zone small footprint reduced water use high throughput effective for very fine particles Please click Additional Files below to see the full abstract

The Fundamentals, Unique Features and Performance of A Newly Improved Packed Column Jig for Phosphate Processing

The packed column jig (PCJ) is an innovative gravity separation device. PCJ was patented 20 years ago, but its commercial application only began recently after three significant improvements were implemented: 1) new design of packing and feeding system to overcome the plugging problem, 2) computer control to optimize operating parameters, and 3) semi-industrial testing to obtain the optimal design parameters. This paper discusses the fundamentals behind the superior performance of PCJ, demonstrates its unique features that result in energy and operating costs savings, and presents two industrial applications, one for separating silica from phosphate and another for separating dolomite from phosphate. The results shown in the table below are perhaps the best gravity separation results on phosphate. Please click Additional Files below to see the full abstract

Optical heterodyne micro-vibration detection based on all-fiber acousto-optic superlattice modulation

We propose a configuration of optical heterodyne micro-vibration detection based on an all-fiber acousto-optic superlattic modulation structure that acts as both frequency shifter and reflector, simultaneously. The vibration information within the frequency range between 1 Hz to 150 kHz of a piezoelectric mirror (PZM) has been experimentally measured by using this all-fiber optical heterodyne detection configuration. The minimal measurable vibration amplitude and the resolution are around 0.013 nm and 10 pm in the region of tens to hundreds of kilohertz, respectively. The configuration not only has advantages of compact size, easy alignment and non-contact measurement, but also gains high accuracy, which provides a promising alternative and could be applied in the compact and portable instruments based on optical heterodyne detection

Flexible hydrogen fuel cell fabricated on paper with embedded aluminium foil

Direct hydrogen fuel cells are generally heavy and rigid systems based on metal or plastic materials, which are not suitable for various miniwatt and flexible devices. In this study, we have developed a lightweight and flexible fuel cell based on paper substrate embedded with an Al foil inside, which is used as an in-situ hydrogen source by reaction with an electrolyte solution during operation. Benefited from the inhibited hydroxyl transportation by the porous cellulose network, the vigorous Al corrosion reaction is well controlled even though strong alkaline electrolyte is adopted, so that the fuel cell can be discharged for more than 5 hours at 1 mA cm-2 (0.83 V) with only 3.5 mg Al foil. The corresponding faradaic and energy efficiencies are as high as 72% and 18.3%, respectively. The fuel cell flexibility is also quite good when facing different bending angles. Considering its moderate power output, this flexible paper-based hydrogen fuel cell is especially suitable for powering various miniwatt and flexible devices, such as wearable electronics, biosensors, RFID tags, etc. However, higher power can be obtained by suitable stacking of the fuel cell

What’s retinoic acid got to do with it? Retinoic acid regulation of the neural crest in craniofacial and ocular development

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151310/1/dvg23308.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151310/2/dvg23308_am.pd

SoccerNet 2023 Challenges Results

peer reviewedThe SoccerNet 2023 challenges were the third annual video understanding challenges organized by the SoccerNet team. For this third edition, the challenges were composed of seven vision-based tasks split into three main themes. The first theme, broadcast video understanding, is composed of three high-level tasks related to describing events occurring in the video broadcasts: (1) action spotting, focusing on retrieving all timestamps related to global actions in soccer, (2) ball action spotting, focusing on retrieving all timestamps related to the soccer ball change of state, and (3) dense video captioning, focusing on describing the broadcast with natural language and anchored timestamps. The second theme, field understanding, relates to the single task of (4) camera calibration, focusing on retrieving the intrinsic and extrinsic camera parameters from images. The third and last theme, player understanding, is composed of three low-level tasks related to extracting information about the players: (5) re-identification, focusing on retrieving the same players across multiple views, (6) multiple object tracking, focusing on tracking players and the ball through unedited video streams, and (7) jersey number recognition, focusing on recognizing the jersey number of players from tracklets. Compared to the previous editions of the SoccerNet challenges, tasks (2-3-7) are novel, including new annotations and data, task (4) was enhanced with more data and annotations, and task (6) now focuses on end-to-end approaches. More information on the tasks, challenges, and leaderboards are available on https://www.soccer-net.org. Baselines and development kits can be found on https://github.com/SoccerNet

Processing Mineralogy Study on Lead and Zinc Oxide Ore in Sichuan

The processing mineralogy characteristics of an oxidized lead-zinc ore from Sichuan were studied systematically using numerous modern instruments. Results showed that lead and zinc oxide content in the ore exceeded the minimum industrial grade, and also included a relatively high concentration of silver and iron. This ore is composed of many different minerals. Major zinc-containing minerals include sphalerite, hemimorphite, smithsonite, hydrozincite, zinc-containing baileychlore, and zinc-containing dolomite and calcite. Lead-containing minerals are primarily galena and cerussite with small amounts of dechenite, cesaronite, anglesite, limonite and coronadite. Gangue minerals include dolomite and calcite. Dissemination size for the main minerals ranges from medium (0.04 mm) to fine (0.02 mm). All the valuable minerals are well liberated, including galena, sphalerite, cerussite, calamine, and smithsonite. However, the dissemination relationships are complex. Lead is concentrated mainly in galena and cerussite, while zinc occurs primarily in sphalerite, calamine, and smithsonite. The theoretical recovery for lead and zinc were estimated at 72% and 67%, respectively

A Novel Extraction Method for Wildlife Monitoring Images with Wireless Multimedia Sensor Networks (WMSNs)

In remote areas, wireless multimedia sensor networks (WMSNs) have limited energy, and the data processing of wildlife monitoring images always suffers from energy consumption limitations. Generally, only part of each wildlife image is valuable. Therefore, the above mentioned issue could be avoided by transmitting the target area. Inspired by this transport strategy, in this paper, we propose an image extraction method with a low computational complexity, which can be adapted to extract the target area (i.e., the animal) and its background area according to the characteristics of the image pixels. Specifically, we first reconstruct a color space model via a CIELUV (LUV) color space framework to extract the color parameters. Next, according to the importance of the Hermite polynomial, a Hermite filter is utilized to extract the texture features, which ensures the accuracy of the split extraction of wildlife images. Then, an adaptive mean-shift algorithm is introduced to cluster texture features and color space information, realizing the extraction of the foreground area in the monitoring image. To verify the performance of the algorithm, a demonstration of the extraction of field-captured wildlife images is presented. Further, we conduct a comparative experiment with N-cuts (N-cuts), the existing aggregating super-pixels (SAS) algorithm, and the histogram contrast saliency detection (HCS) algorithm. A comparison of the results shows that the proposed algorithm for monitoring image target area extraction increased the average pixel accuracy by 11.25%, 5.46%, and 10.39%, respectively; improved the relative limit measurement accuracy by 1.83%, 5.28%, and 12.05%, respectively; and increased the average mean intersection over the union by 7.09%, 14.96%, and 19.14%, respectively