Preparation of High Performance Grccn Alumina Ceramic Balls by Roller Production Waste

To reuse roller waste as a raw material of high performance green ceramic balls, three kinds of white alumina ceramic balls whose wear resistance were 2-3 times of the best high alumina ceramic ball with 90% Al2O3 were prepared, and the Al2O3 content of the prepared balls was 75%. It is found that the effect of calcia and magnesia on the wear resistance of ceramic balls is contrast to the accepted one： the wear rate of the ceramic balls prepared in CaO-Al2O3-SiO2 system is the lowest and the wear rate of the ceramic balls prepared in MgO-Al2O3-SiO2 is the highest. The main crystal phase of the ceramic ball is mullite and corundum. The ceramic ball granular is uniform and fine with 4-5 μm average size. The pore diameter is about 2 μm. The wear way of the ceramic balls is mainly transcrystalline fracture.

The Interaction Effects of the Parameters on Optimization Design in Paper Production Waste Usage on Alkali-Activated Slag with Taguchi Method

The paper investigates the second-order interactions of parameters in an alkali-activated mixture of paper production waste(PPW)and blast furnace slag(BFS)in Taguchi method.The PPW including lime mud(LM)and paper sludge(PS).This paper provides the experimental models to assess the compressive and flexural strength of them at 7-day and 28-day.The results have shown that the second-order interactions between PPW and alkali-activated activator exists in each experimental model,and the significant interactions affect the selection of optimal compositions.Compared with the interactions between the PPW themselves,the interactions between PPW and alkali-activated parameters are the main significant factors affecting its physical properties.In each experimental model,the maximum compressive strength was 47.41 MPa in 7-day and 65.64 MPa in 28-day.Compared with the confirmatory experiments,the deviation of prediction calculated by experimental models was 3.08%and 0.56%,respectively.The maximum flexural strength was 5.74 MPa in 7-day and 5.96 MPa in 28-day;compared with the confirmatory experiments,the deviation of prediction calculated by experimental models was 5.40%and 0.17%.Considering the influence of circular materials,30%of PPW should be a suitable ratio to replace BFS as the raw material of alkali-activated slag(AAS).

Genetic Toxic Effects of Rare-earth Waste and Its Products on Peacock Fish

The micro-nuclei and abnormal nuclei rates of peacock fish are tested,genetic toxic effects of rare-earth waste and its products(cement,plastic) on peacock in water are investigated.Results show that the leachate of rare-earth waste can lead to micronuclei and abnormal nuclei rates of peacock fish an obvious increase(P<0.01). Products made of the waste cause the micronuclei rate to be increased because of its low radio active action,but the change in abnormal nuclei rate can't reach a remarkable level.It shows that rare-earth waste has a certain effect of causing mutation on aquatic organism.Harmfulness of products made from this waste is decreased largely,and resources can be effectively saved.

Extraction and recycling technologies of cobalt from primary and secondary resources:A comprehensive review

Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially depleted cobalt resources,leading to a crisis of cobalt resource supply.The paper examines cobalt ore reserves and distribution,and the recent development and consumption of cobalt resources are summarized as well.In addition,the principles,advantages and disadvantages,and research status of various methods are discussed comprehensively.It can be concluded that the use of diverse sources(Cu-Co ores,Ni-Co ores,zinc plant residues,and waste cobalt products)for cobalt production should be enhanced to meet developmental requirements.Furthermore,in recovery technology,the pyro-hydrometallurgical process employs pyrometallurgy as the pretreatment to modify the phase structure of cobalt minerals,enhancing its recovery in the hydrometallurgical stage and facilitating high-purity cobalt production.Consequently,it represents a promising technology for future cobalt recovery.Lastly,based on the above conclusions,the prospects for cobalt are assessed regarding cobalt ore processing and sustainable cobalt recycling,for which further study should be conducted.

Levels of Chemical Toxicants in Waterpipe Tobacco and Waterpipe Charcoal Solid Waste

This work provides insights on waterpipe tobacco and waterpipe charcoal as potential sources of environmental toxicants. Selected harmful and potentially harmful constituents (HPHCs) from ten U.S. commercial waterpipe tobacco filler products (before and after electric heating) and five waterpipe charcoal products (before and after burning) were investigated. The differences in quantities of HPHCs between the evaluated products appear to be affected by raw material properties and/or the manufacturing processes involved in product production. Trace metal quantities in waterpipe tobacco and charcoal products were observed after heating or burning conditions compared to unheated or unburned conditions, which could impact the environment through the generation of toxic tobacco product waste. This study demonstrates that waterpipe tobacco and waterpipe charcoal contain substantial quantities of benzo[a]pyrene (B[a]P) and trace metals (i.e., selenium, arsenic, cadmium, chromium, cobalt, lead, nickel) before use and that extensive and varied changes in trace metal quantities take place as a result of heating, and more studies are needed to estimate the magnitude of the environmental impact of waterpipe tobacco use.

Use of Low Radioactive Rare-earth Waste for Sewage Treatment

Low radioactive rare earth waste (containing 232 Th,specific activity 5 000 8 000 Bq·kg -1 ) were diluted 20 times by cement,sand and carbide ash and were made into special cement.The radioactivity of this special cement complied with the healthy protect standard for radioactive materials (GB6566 86).Test results showed that this special cement could lower COD,the degradation rate increased as the time went on.In acidic medium,this special cement could remove E Coli effectively.Applying aeration and adding lumps of cement,the degradation of COD versus time complied with Logistic model through fitting by computer.The two “S” curves indicated that aeration and adding lumps of cement had synergistic action on sewage treatment.

Neutronic analysis of deuteron-driven spallation target

Deuteron-driven spallation targets have garnered attention recently because they can provide high-energy neutrons to transmute long-lifetime fission products.In this study,the Geant4 toolkit was used to simulate the inter-action between a deuteron beam at 500 MeV and a com-posite target composed of alternating lead-bismuth eutectic(LBE)and water.The water was used because it may be employed as a target coolant.The energy spectrum,neu-tron yield,average energy,and total energy of the emitted neutrons were calculated for different thicknesses and thickness ratios between the LBE and water.For a constant target thickness,the neutron yield increases with an increasing thickness ratio of LBE to H 2 O,while the aver-age energy of the emitted neutrons decreases with an increasing in the aforementioned thickness ratio.These two aspects support the use of a pure target,either LBE or water.However,with an increasing LBE-to-H 2 O thickness ratio,the total energy of the emitted neutrons increases and then decreases.This result supports the addition of water into the LBE target.The angular distributions of the emitted neutrons show that the rear of the target is suit-able for loading nuclear waste containing minor actinides and long-lifetime fission products.

Purification of scandium from concentrate generated from titanium pigments production waste

Nowadays 80%of scandium in China is obtained from titanium pigments production waste through a complex purification process.The study mainly focused on the purification of Sc from its concentrate generated from titanium pigments production waste by solvent extraction.Several extractants have been tried and 10%D_(2)EHPA-5%TBP-85%sulfonated kerosene exhibited the best extraction performance towards Sc in 7 mol/L H_(2)SO_(4)solution,so it was selected as the oil phase.0.5%of H_(2)O_(2)was added into the concentrated solution which can effectively inhibit the extraction of Ti.Both the extraction and back extraction parameters are optimized.The preferred extraction conditions were obtained,i.e.,acidity:7 mol/L H_(2)SO_(4),the phase ratio A/O:10,room temperature,mixed contact time:30 min,Sc concentrate:10 g/L,that the extraction rate of Sc in the above conditions was nearly 100%.NaOH was used for back extraction with the stripping rate 99%on the following conditions:5 mol/L NaOH stripping for 30 min at a phase ratio A/O:1 at 90℃.Finally,H_(2)C_(2)O_(4)was used to further purify the back extraction product and Sc_(2)(C_(2)O_(4))_(3)precipitant fo rmed.The final product Sc_(2)O_(3)with a purity over 99.5%was obtained by calcining Sc_(2)(C_(2)O_(4))_(3)at 1000℃for 2 h.A conceptual process for Sc purification was put forward and proved.The total recovery yield of Sc in the whole process is 95%.

Delignification of disposable wooden chopsticks waste for fermentative hydrogen production by an enriched culture from a hot spring

Hydrogen （H2） production from lignocellulosic materials may be enhanced by removing lignin and increasing the porosity of the material prior to enzymatic hydrolysis. Alkaline pretreatment conditions, used to delignify disposable wooden chopsticks （DWC） waste, were investigated. The effects of NaOH concentration, temperature and retention time were examined and it was found that retention time had no effect on lignin removal or carbohydrate released in enzymatic hydrolysate. The highest percentage of lignin removal （41%） was obtained with 2% NaOH at 100℃, correlated with the highest carbohydrate released （67 mg/gpretreated DWC） in the hydrolysate. An enriched culture from a hot spring was used as inoculum for fermentative H2 production, and its optimum initial pH and temperature were determined to be 7.0 and 50℃, respectively. Furthermore, enzymatic hydrolysate from pretreated DWC was successfully demonstrated as a substrate for fermentative H2 production by the enriched culture. The maximum H2 yield and production rate were achieved at 195 mL H2/g total sugarsconsumed and 1 16 mL Hz/（L.day）, respectively.

Hydrolysis Lignin as a Sorbent and Basis for Solid Composite Biofuel

New powdered sorbent Lignosorb based on the hydrophobized hydrolysis lignin has been developed at the Belarusian State University. Hydrolysis lignin is a commercial waste product of biomass processing in the hydrolysis production of ethanol. In spite of the various proposals for hydrolysis lignin usage, the wide application has not found yet. Special area of hydrophobized hydrolysis lignin usage as a sorbent for oil spills removal and oil products waste recovery is discussed. Lignosorb, thanks to the rather high bulk density, can be applied manually or mechanically by conventional sprayers. It does not sink after oil adsorption and transforms liquid oil film on the water surface into the solid mass. The solid product is a complete mass and is easily collected from the surface of water. Lignosorb when blended with oil products waste in the volume forms the granular free-running product. The rheological properties of the Lignosorb suspensions in oil products at different sorbent to oil product ratio have been estimated. Saturated by different oil products Lignosorb one can granulate or pellet and utilize as a composite solid fuel including the co-firing regime of combustion. It has the higher heating value of 32.1 - 38.8 MJ/kg while the coal has 20.9 - 30.1 MJ/kg. It has been shown that composite fuel burning has less longstanding inflammation stage, more long stable burning stage and less longstanding phase of smoldering in the comparison to wood and Lignosorb burning.

Integrated Assessment of Mineral Resources and Environmentin Mid-South of Shandong Province

On the bases of the field survey and a large number of testing data, we process the qualitative and quantitative assessment of the mine environment in the mid south of Shandong Province using the following grade Ⅰ factors:the surface subsidence in mining area, the three wastes of mine industries, the pollution sources, the surface water pollution, the underground water pollution and the air pollution. By means of emitting factor judgment and water quality indexes, we locate pollution sources, main pollutants, pollution type and pollution grade in the study area. Using the MAPGIS, we draw a zonality map of the mine environment. This paper attempts to offer a concrete example, including valuable assessment method, data and conclusion, for the assessment of mine environment from the integrated assessment of mineral resources and mine environment. This research is oriented towards the sustainable development and the ecological environment optimization.

A comparative study on the alternating mesophilic and thermophilic two-stage anaerobic digestion of food waste

An alternating mesophilic and thermophilic two stage anaerobic digestion （AD） process was conducted. The temperature of the acidogenic （A） and methanogenic （M） reactors was controlled as follows： System 1 （S1） mesophilic A-mesophilic M; （S2） mesophilic A-thermophilic M; and （S3） thermophilic A-mesophilic M. Initially, the AD reactor was acclimatized and inoculated with digester sludge. Food waste was added with the soluble chemical oxygen demand （SCOD） concentrations of 41.4-47.0 g/L and volatile fatty acids of 2.0-3.2 g/L. Based on the results, the highest total chemical oxygen demand removal （86.6%） was recorded in S2 while S3 exhibited the highest SCOD removal （96.6%）. Comparing S1 with S2, total solids removal increased by 0.5%;S3 on the other hand decreased by 0.1% as compared to S1. However, volatile solids （VS） removal in S1, S2, and S3 was 78.5%, 81.7%, and 79.2%, respectively. S2 also exhibited the highest CH4 content, yield, and production rate of 70.7%, 0.44 L CH4/g VSadded, and 1.23 L CH4/（L.day）, respectively. Bacterial community structure revealed that the richness, diversity, evenness, and dominance of S2 were high except for the archaeal community. The terminal restriction fragments dendrogram also revealed that the microbial community of the acidogenic and methanogenic reactors in S2 was distinct. Therefore, S2 was the best among the systems for the operation of two-stage AD of food waste in terms of CH4 production, nutrient removal, and microbial community structure.