Hydrometallurgical process and recovery of valuable elements for limonitic laterite:A review

Nickel is a strategic resource in social life and defense technology,playing an essential role in many fields,such as alloys and batteries.With the decrease in nickel sulfide,it is of great significance to extract nickel from laterite.The limonitic laterite is a kind of rich nickel-cobalt-scandium resource.At present,there are few reviews on the extraction of limonitic laterite.This study reviews the hydrometallurgical processes for limonitic laterite ores and the methods of recovering valuable elements.The mineralogical characteristics are analyzed,and the typical mineral compositions are summarized.The main hydrometallurgical processes are compared and discussed,including reduction roasting-ammonia leaching,sulfuric acid pressure leaching,nitric acid pressure leaching,and the atmospheric nitric acid leaching(DNi process).The methods of recovering nickel,cobalt,scandium,and iron are emphatically outlined.Finally,reasonable suggestions are proposed for comprehensive utilization.This study can provide a reference for industrial development and diversified applications.

Extraction of Valuable Metals from Titanium-bearing Blast Furnace Slag by Acid Leaching

To realize the resource utilization of the valuable metals in the titanium-containing blast furnace slag,the process route of “hydrochloric acid leaching-electrolysis-carbonization and carbon dioxide capture-preparation of calcium carbonate” was proposed.In this study,the influences of process conditions on the leaching rates of calcium,magnesium,aluminum,and iron and the phases of the leaching residue were investigated for the leaching process.The experimental results show that the HCl solution could selectively leach the elements from the titanium-containing blast furnace slag.The better leaching conditions are the HCl solution concentration of 4 mol/L,the leaching time of 30 min,the ratio of liquid volume to solid gas of 10 mL/g,and the stirring paddle speed of 300 r/min.Under the conditions,the leaching rates of calcium,magnesium,aluminum,and iron can reach 85.87%,73.41%,81.35%,and 59.08%,and the leaching rate of titanium is 10.71%.The iron and the aluminum are removed from the leachate to obtain iron-aluminum water purification agents,and the magnesium is removed from the leachate to obtain magnesium hydroxide.The leaching residue phase is dominated by perovskite,followed by magnesium silicate and tricalcium aluminate,and the titaniumrich material could be obtained from the leaching residue by desiliconization.

Comprehensive reutilization of herbal waste:Coproduction of magnolol,honokiol,and β-amyrin from Magnolia officinalis residue

Herbal extraction residues(HERs)cause serious environmental pollution and resource waste.In this study,a novel green route was designed for the comprehensive reutilization of all components in HERs,taking Magnolia officinalis residues(MOR)as an example.The reluctant structure of MOR was first destroyed by alkali pretreatment to release the functional ingredients(magnolol and honokiol)originally remaining in MOR and to make MOR more accessible for hydrolysis.A metal–organic frame material MIL-101(Cr)with a maximum absorption capacity of 255.64 mg g^(-1)was synthesized to absorb the released honokiol and magnolol from the pretreated MOR solutions,and 40 g L^(-1)reducing sugars were obtained with 81.8%enzymatic hydrolysis rate at 10%MOR solid loading.Finally,382 mg L-1β-amyrin was produced from MOR hydrolysates by an engineered yeast strain.In total,1 kg honokiol,8 kg magnolol,and 7.64 kg β-amyrin could produce from 1 ton MOR by this cleaner process with a total economic output of 170,700 RMB.

Technological advancement and industrialization path of Sinopec in carbon capture,utilization and storage,China

Carbon capture,utilization and storage(CCUS)technology is an important means to effectively reduce carbon emissions from fossil energy combustion and industrial processes.With the crisis of climate change,CCUS has attracted increasing attention in the world.CCUS technology as developed rapidly in China is technically feasible for large-scale application in various industries.The R&D and demonstration of CCUS in China Petroleum&Chemical Corporation(Sinopec)are summarized,including carbon capture,carbon transport,CO_(2)enhanced energy recovery(including oil,gas,and water,etc.),and comprehensive utilization of CO_(2).Based on the source-sink matching characteristics in China,two CCUS industrialization scenarios are proposed,namely,CO_(2)-EOR,CO_(2)-driven enhanced oil recovery using centralized carbon sinks in East China and CO_(2)-EWR,CO_(2)-driven enhanced water recovery(EWR)using centralized carbon sources from the coal chemical industry in West China.Finally,a CCUS industrialization path from Sinopec's perspective is suggested,using CO_(2)-EOR as the major means and CO_(2)-EWR,CO_(2)-driven enhanced gas recovery(CO_(2)-EGR)and other utilization methods as important supplementary means.

Analysis and Prospect of Waste Heat Utilization from Blast Furnace Slag Flushing

Estimating the residual heat of blast furnace slag flushing in China,classifying and introducing the current proposed methods of slag flushing waste heat utilization,and listing existing cases.In order to better save energy and water in the slag flushing process of blast furnaces,an ideal comprehensive cascade utilization system scheme for annual recovery of waste heat is proposed.Based on the measured waste heat data of a steel plant,design calculations are carried out to further analyze the economic feasibility of the new scheme and provide reference for its promotion and application.

Comprehensive Utilization and Control Measures of Iron and Steel Slag

With the increase of steel production,the amount of steel slag piled up is on the rise.The article analyzes the current situation of blast furnace slag utilization,elaborates on the current treatment technology of blast furnace slag,and points out that in the future,the utilization of blast furnace slag will develop towards the direction of developing high value-added products,and the sensible heat recovery rate of blast furnace slag is expected to increase.Analyze the current application status and treatment process of converter slag.The comprehensive treat-ment technology of converter slag is limited by multiple factors,and it is proposed to control converter slag from the production source through"slag recycling".

Lithium extraction from hard rock lithium ores(spodumene,lepidolite,zinnwaldite,petalite):Technology,resources,environment and cost

Lithium production in China mainly depends on hard rock lithium ores,which has a defect in resources,environment,and economy compared with extracting lithium from brine.This paper focuses on the research progress of extracting lithium from spodumene,lepidolite,petalite,and zinnwaldite by acid,alkali,salt roasting,and chlorination methods,and analyzes the resource intensity,environmental impact,and production cost of industrial lithium extraction from spodumene and lepidolite.It is found that the sulfuric acid method has a high lithium recovery rate,but with a complicated process and high energy consumption;alkali and chlorination methods can directly react with lithium ores,reducing energy consumption,but need to optimize reaction conditions and safety of equipment and operation;the salt roasting method has large material flux and high energy consumption,so require adjustment of sulfate ratio to increase the lithium yield and reduce production cost.Compared with extracting lithium from brine,extracting lithium from ores,calcination,roasting,purity,and other processes consume more resources and energy;and its environmental impact mainly comes from the pollutants discharged by fossil energy,9.3-60.4 times that of lithium extracted from brine.The processing cost of lithium extraction from lepidolite by sulfate roasting method is higher than that from spodumene by sulfuric acid due to the consumption of high-value sulfate.However,the production costs of both are mainly affected by the price of lithium ores,which is less competitive than that of extracting lithium from brine.Thus,the process of extracting lithium from ores should develop appropriate technology,shorten the process flow,save resources and energy,and increase the recovery rate of related elements to reduce environmental impact and improve the added value of by-products and the economy of the process.

Research and Application Progress of Straw

Straw is a general term for the stem and leaf parts of mature crops,and is a multi-purpose renewable biomass energy resource in the agricultural ecosystem.The prospect of comprehensive utilization of straw has become broad with the development of agricultural production,the advancement of science and technology,and the improvement of the level of agricultural mechanization.The comprehensive utilization of straw plays an important role in enhancing the sustainable development ability of agricultural economy and improving the current situation of comprehensive utilization of agricultural resources in my country.This paper briefly combs the development history of straw and the prospect and current situation of comprehensive utilization,and expounds the separation technology of straw components,straw man-made panels,straw concrete,straw returning technology and oyster mushroom cultivation.It focuses on the description of the component separation technology of straw and the manufacturing process of straw-based panels.The different separation methods and separation effects of cellulose,hemicellulose and lignin were introduced in detail,and the static yield strength(MOR),internal bonding strength(IB)and water absorption thickness of several common straw-based panels were compared and studied(TS).Finally,it summarizes the benefit analysis of the comprehensive utilization of straw by scholars from the perspective of economics,and summarizes the corresponding measures based on their own views.

Advances in Research on Comprehensive Utilization of Tea Waste

China is a big producer and consumer of tea. A huge amount of tea waste is produced in China every year, resulting in environmental pollution and enormous natural resources waste. From the perspective of utilization way, this pa- per summarized the research progresses in tea waste as a raw material for ex- tracting active ingredients and preparing absorbent, activated carbon, bio-organic fer- tilizer, animal feed and nutrients for edible fungi cultivation. In addition, the develop- ment trend of comprehensive utilization of tea waste was prospected. It is found that the comprehensive utilization of tea waste using a variety of techniques can im- prove the utilization efficiency of tea waste and reduce production costs. Finally, a simple and practical comprehensive utilization program was proposed to provide a reference for practical application.

A novel method for comprehensive utilization of sintering dust

A novel process aimed at the comprehensive utilization of sintering dust was developed by combining wetting grinding with sulfidization flotation. The mineralogical characteristics of the sintering dust and products were studied by powder wettability analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and mineral liberation analyzer（MLA）. It was found that the primary lead species was laurionite and most of the particles were overwrapped with KCl. Wetting grinding was shown to accelerate the dispersion of sintering dust and transform the KCl overlay to a leachate with 20.78 g/L of K＋. A lead and silver concentrate consisting of 40.82% of Pb and 0.96 kg/t of Ag was achieved, while an iron concentrate with 60.89% of Fe was gained as tailings among sulfidization flotation. The recoveries of Pb, Ag and Fe were 89.57%, 87.85% and 88.58%, respectively. The results indicate that this method is a feasible and promising process for the comprehensive utilization of sintering dust.

Iron ore tailings used for the preparation of cementitious material by compound thermal activation

In the background of little reuse and large stockpile for iron ore tailings, iron ore tailing from Chinese Tonghua were used as raw material to prepare cementitious materials. Cementitious properties of the iron ore tailings activated by compound thermal activation were studied. Testing methods, such as XRD, TG-DTA, and IR were used for researching the phase and structure variety of the iron ore railings in the process of compound thermal activation. The results reveal that a new cementitious material that contains 30wt% of the iron ore tailings can be obtained by compounded thermal activation, whose mortar strength can come up to the standard of 42.5 cement of China.

Chemical constituents,biological functions and pharmacological effects for comprehensive utilization of Eucommia ulmoides Oliver

Eucommia ulmoides Oliver is a native plant and valuable tonic Chinese medicine in China with a long history,great economic value and comprehensive development potential.Traditionally,the comprehensive utilization rate of E.ulmoides Oliv.is still very low,only bark has been used as medicine and other parts of Eucommia ulmoides Oliv.cannot be fully utilized,even the leaves have been well utilized in food products in Japan in the past decades.In order to improve the comprehensive utilization efficiency of E.ulmoides Oliv.,in this review,we summarized the varieties and contents of main active compounds,biological functions and pharmacological effects in different parts of E.ulmoides Oliv.The findings suggest that other parts of E.ulmoides Oliv.could replace the bark of E.ulmoides Oliv.to some extent besides of their respective applications.The unique and extensive physiological functions between different parts of E.ulmoides Oliv.indicate that the comprehensive utilization of E.ulmoides Oliv.has a wide space to develop,which is also an effective way to protect E.ulmoides Oliv.resources and improve its the utilization rate.

Application of suspension magnetization roasting as technology for high-efficiency separation of valuable iron minerals from high-iron bauxite

A technology for suspension magnetization roasting−magnetic separation was proposed to separate iron minerals for recovery.The optimum parameters were as follows:a roasting temperature of 650℃,a roasting time of 20 min,a CO concentration of 20%,and particles with a size less than 37μm accounting for 67.14%of the roasted product.The total iron content and iron recovery of the magnetic concentrate were 56.71%and 90.50%,respectively.The phase transformation,magnetic transition,and microstructure evolution were systematically characterized through iron chemical phase analysis,X-ray diffraction,vibrating sample magnetometry,X-ray photoelectron spectroscopy,and transmission electron microscopy.The results demonstrated the transformation of hematite to magnetite,with the iron content in magnetite increasing from 0.41%in the raw ore to 91.47%in the roasted product.

Formation cause,composition analysis and comprehensive utilization of rare earth solid wastes

Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were ...

Extraction of manganese and zinc from their compound ore by reductive acid leaching

Comprehensive utilization of low grade manganese?zinc compound ore containing lead and silver with a method of reductive acid leaching was studied.According to theφ?pH diagram of Mn?Zn?H2O system,Mn and Zn can be leached simultaneously in the pH range of?2to5.61.The results showed that both hydrogen peroxide and sucrose were effective reductants which could intensify the simultaneous leaching of Mn and Zn into leachate as well as enrich Pb and Ag in the residue.95.88%of Mn and99.23%of Zn were extracted when the compound ore was leached with hydrogen peroxide in sulfuric acid media,meanwhile the contents of Pb and Ag in the residue were enriched to13.21%and489.36g/t,respectively.When sucrose was used as the reductant,the leaching efficiencies of Mn and Zn separately achieved98.26%and99.62%,and contents of Pb and Ag in the residue were as high as13.92%and517.87g/t,respectively.

Research Progress of Quality Characteristics and Comprehensive Utilization of Mung Beans

Mung bean is one of the major legume crops in China, and its nutritional quality and processing quality directly affect the development of mung bean processing industry. In order to promote the development of mung bean processing industry, the research progress of mung bean quality characteristics, including physical quality, nutritional quality, medicinal value and the processing quality, were summarized based on literatures both at home and abroad, and the current exploitation status of starch, protein, dietary fiber, resistant starch, flavonoids and superoxide dismutase of mung bean was also reviewed. In order to promote the development of mung bean processing industry, it should strengthen the research on quality characteristics and functional ingredients of mung bean, pay attention to the development of healthy products, improve the processing technology, and cultivate a group of leading mung bean processing companies with strong competence in the market.

New technique of comprehensive utilization of spent Al_2O_3-based catalyst

A new technology was developed to recover multiple valuable elements from the spent Al2O3-based catalyst by X-ray phase analysis and exploratory experiments. The experimental results show that in the condition of roasting temperature of 750℃ and roasting time of 30 min, molar ratio of Na2O to Al2O3 of 1.2, the leaching rates of alumina, vanadium and molybdenum in the spent catalyst are 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by precipitators A and B, and the precipitation rates of vanadium and molybdenum are 94.8% and 92.6%. Al（OH）3 was prepared from sodium aluminate solution in the carbonation decomposition process, and the purity of Al2O3 is 99.9% after calcination, the recovery of alumina reaches 90.6% in the whole process; the Ni-Co concentrate was leached by sulfuric acid, a nickel recovery of 98.2% and cobalt recovery over 98.5% can be obtained under the experimental condition of 30% H2SO4, 80℃, reaction time 4 h, mass ratio of liquid to solid 8, stirring rate 800r/min.

Silting in the Lower Courses of Tidal Sluices in China

Serious sediment deposition often occurs after the construction of tidal sluices in small or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood discharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed. Different problems of silting near tidal sluices for different types of estuaries are summed up, at the same time, corresponding methods are given to solve these problems, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.

Review and prospect of comprehensive straw utilization and government policy in China

The comprehensive use and efficient management of straw are significant for agriculture's green and low carbon transformation.This paper uses literature research and comparative analysis to systematically review the literature on comprehensive straw utilization and governance policy research in China over the past five years.The current literature has explored two major directions:regional and industrial policies and the main actors involved in the comprehensive use of straw.The research is complementary and fruitful concerning both micro and macro perspectives;however,the extant literature suffers from a lack of attention to straw intermediaries and enterprises and a lack of research across time.Therefore,this paper provides an outlook for future research.In the future,scholars should pay more attention to straw intermediaries and enterprises,conduct continuous observations of multiple regions over time to obtain panel data,and further test the heterogeneity of factors to obtain more scientific and valid results.

Key Technology Research on the Efficient Exploitation and Comprehensive Utilization of Resources in the Deep Jinchuan Nickel Deposit

To understand the resource features and geology in the deep Jinchuan nickel deposit, difficult geological conditions were systematically analyzed, including high stress, fragmentized ore rock, prevalent deformation, difficult tunnel support, complicated rock mechanics, and low mining recovery. An integrated technology package was built for safe, efficient, and continuous mining in a deep, massive, and complex nickel and cobalt mine. This was done by the invention of a large-area continuous mining method with honeycomb drives; the establishment of ground control theory and a technology package for high-stress and fragmented ore rock： and the development of a new type of backfilling cement material, along with a deep backfilling technology that comprises the pipeline transport of high-density slurry with coarse aggregates. In this way, good solutions to existing problems were found to permit the efficient exploitation and comprehensive utilization of the resources in the deep Jinchuan nickel mine. In addition, a technological demonstration in an underground mine was performed using the cemented undercut-and-fill mining method for stressful, frag- mented, and rheological rock.