The efficient extraction and utilization of oil and natural gas are closely related to the security of China′s energy development.Continuously improving the efficiency of oil and gas extraction and resource utilization is an important development direction for China's oil and gas extraction.However，salt scaling is often accompanied by the exploitation of oil and gas fields，leading to the blockage of key equipment such as pipelines，drilling tools，and oil and gas wells and seriously reducing the efficiency of oil and gas exploitation.To conduct in-depth analyses of the principles behind salt scale formation in oil and gas fields and develop a series of anti-salting techniques is the direction to address the challenge.The research results on the composition and mechanism of salt crystallization in existing oil and gas fields were reviewed. The commonly used antisalt technologies were systematically analyzed.The types and principles of developed antisalt agents were summarized.The screening principles of antisalt agents，the challenges faced in their research，and the future development trends were summarized，providing theoretical support and practical guidance for the design and development of new antisalt agents in future oil and gas field system.

Hydrogen energy is considered to be one of the most potential alternative energy sources for fossil energy.Hydrogen production by electrolysis of water is a simple and effective method，but the hydrogen evolution reaction（HER） and oxygen evolution reactions（OER） involved in this process are slow kinetic reactions which seriously hindering the commercialization of hydrogen production by water electrolysis.Therefore，the development of low-cost，efficient and stable catalysts to improve the efficiency of the water electrolysis process is an urgent problem to be solved.Boron nitride nanosheets（BNNSs） have shown excellent catalytic activity in the electrochemical hydrogen and oxygen evolution，due to their unique two-dimensional structure，excellent oxidation resistance，thermal stability and wide gap.Therefore，BNNSs showed broad application prospect in the field of water splitting.The main preparation methods of BNNSs at home and abroad in recent years were reviewed，including mechanical stripping，chemical exfoliation and chemical vapor deposition，and their advantages and disadvantages were analyzed.In addition，the application of BNNSs in water electrolysis was reviewed，including HER and OER.Finally，the current problem and solution were summarized and the future research direction was prospected.

In recent years，with the rapid rise of the new energy industry，the application of lithium-ion batteries in various fields has continued to surge.However，the high performance of commercial lithium-ion batteries with graphite anodes can only be realized above 0 ℃，which limits the application of the batteries in low-temperature cold regions.In order to meet the demand for low-temperature applications of lithium-ion batteries，the mechanism was explored by analyzing the limiting factors of graphite low-temperature environments，providing insights into the key factors contributing to the poor low-temperature performance of lithium-ion batteries.It was focused on the feasible strategies and solutions to improve the low-temperature performance，and the latest progress in the engineering of low-temperature anode materials was reviewed in terms of structural design，morphology control，surface and interface modification，and multiphase materials.Finally，the problems to be solved in the field of low-temperature graphite anode materials were discussed.It was aimed to provide valuable insights and guidance for the development of next-generation LIBs with excellent low-temperature electrochemical properties.

In the process of wet-process phosphoric acid production，eutectic phosphorus in phosphogypsum is the key factor leading to the waste of phosphorus resources.Solving the problem of eutectic phosphorus loss is of great significance to phosphoric acid production.In order to reduce the loss of eutectic phosphorus in dihydrate wet-process phosphoric acid process and improve economic efficiency，the production process of wet-process phosphoric acid by dihydrate method without solid phase was simulated in Ca（H₂PO₄）₂-H₃PO₄-H₂SO₄ system.The effects of reaction temperature，liquid P₂O₅ concentration，aging time and liquid SO₃ concentration on the eutectic phosphorus content of phosphogypsum were investigated.The results showed that when the reaction temperature was 75 ℃，the mass fraction of liquid-phase P₂O₅ was 26%，the aging time was 3.0 h，and the excess of 3.0% sulfuric acid（the concentration of SO₃ in liquid phase was 41.19 g/L） was added to the return acid，the eutectic phosphorus content in phosphogypsum was significantly reduced to 0.21%.Comparing the differences in the morphology of calcium sulfate dihydrate crystals formed under different reaction conditions，it was observed that the calcium sulfate dihydrate crystals formed by the reaction system are mainly plate-like and rod-like crystals，and the dominant growth of the long rod-like crystal in the radial direction was beneficial to reduce the content of eutectic phosphorus in phosphogypsum.In this experiment，the change of eutectic phosphorus content and its crystal morphology in phosphogypsum were studied，which was conducive to a more comprehensive understanding of the formation mechanism of eutectic phosphorus.At the same time，it provided reference value for the actual production of dihydrate wet-process phosphoric acid to select appropriate process parameters.

In order to solve the problem of poor cycling performance caused by the dissolution loss of titanium-based lithium ion sieves（H₂TiO₃） during periodic cycling，it was aimed to improve the stability by changing the lattice structure with metal ion doping.The Ni-modified titanium-based lithium ion sieve（Ni-HTO） was prepared by utilizing ball milling for mixing，followed by high-temperature solid-state reaction and ion exchange.The effects of nickel doping on the structure，adsorption performance，and stability of the adsorbent were investigated，and its applicability in lithium extraction from salt lakes was assessed to provide insights for practical applications.The results showed that the dissolution of Ti⁴⁺ in the metatitanic acid ion sieve was reduced after Ni doping.Furthermore，the（002） interplanar spacing of the Ni-modified ion sieve was decreased，which significantly improved the adsorption selectivity for Li⁺.Specifically，the separation factor of Li⁺ to Mg²⁺ reached 281.23，with a saturated adsorption capacity of 30.5 mg/g.The granulated adsorbent（Ni-HTO） was used in the lithium extraction test of Laguocuo Salt Lake brine.The results showed that the adsorption capacity for Li⁺ remained around 9.55 g/L，the average Ti⁴⁺ dissolution loss rate was decreased from 0.68%（unmodified） to 0.20%，and the average selectivity was significantly improved after 20 cycles，which indicated that Ni-HTO had excellent adsorption properties，cyclic stability and selectivity.In summary，the Ni-modified titanium-based lithium ion sieve had great application potential in the field of lithium extraction from salt lakes.

In this study，polycarboxylate superplasticizer（PCE） was used to graft onto graphene oxide（GO），thereby synthesizing a novel GO-based superplasticizer（PCE@GO）.The GO modification experiment was simple and feasible.It not only could overcome the agglomeration issue of GO in cement mortar but also enhanced the mechanical properties of the cement mortar by using grafted PCE@GO as a reinforcing material.The experimental results showed that PCE@GO could be uniformly dispersed in the cement solution，with obviously improved stability，due to the steric hindrance and electrostatic repulsion provided by the PC on the surface of GO，which prevented the agglomeration of GO.Furthermore，PCE@GO also significantly enhanced the mechanical properties of the cement paste：when 0.1%（mass fraction） content of PCE@GO was added，the flexural strength and compressive strength of the cement composite material at 28 d reached the maximum values of 8.0 MPa and 65.4 MPa，respectively，which were 6.7% and 23.2% higher than the GO samples with an addition of 0.1% PCE@GO.The addition of PCE@GO also improved the flowability of the cement mortar and reduced the crystal size of the hydration products，thereby enhancing the performance of the cured composite material.This study provided theory and experimental basis for designing and preparing high performance cement mortar materials，and had certain guiding significance for the application of GO-based materials in cement mortar.

With tetraethoxysilane as silicon source，trimethylchlorosilane as hydrophobic modifier，basalt fiber，basalt fiber high silica fiber composite and high silica fiber as matrix materials，three kinds of SiO₂ aerogel composites were prepared by sol-gel method and supercritical drying technology，and the changes of microstructure and performance of aerogel composites under ultraviolet environment were explored.The results showed that before the ultraviolet aging test，the fiber as the framework of the composite was tightly wrapped by the aerogel，and the two formed a close combination.After the test，the basalt fiber/aerogel composites，basalt fiber high silica fiber/aerogel composites and high silica fiber/aerogel composites all had micro pit structures on their surfaces.A small number of fibers were separated from the aerogel，and the aerogel structure was also becoming loose.The mechanical properties were reduced by 9.8%，11.9%，and 9.1%，respectively，while the thermal conductivity was increased by 8.3%，8.5%，and 5.4%.Based on the theory of equivalent radiation，the prediction equation of UV aging life in natural environment was established.Taking the decline of mechanical properties below 10% as the failure threshold，the ultraviolet aging life in natural environment was predicted to be 10.0，10.8，and 10.9 a，respectively.The three aerogel composites showed the potential of long-term stable service in the ultraviolet radiation environment of bridges，and were expected to be used in the field of bridge fire prevention.

In order to solve the problem of high chlorine content in filter cake during the production of basic magnesium carbonate from the old brine of Qarhan Salt Lake，a new idea of using the old brine of Qarhan Salt Lake to prepare basic magnesium carbonate was put forward.The differences of water consumption and chlorine content between one-step method and two-step method in the preparation of basic magnesium carbonate were studied，and the crystal shape and morphology of the samples were characterized by XRD，SEM and other characterization techniques，and the mechanism of the reaction process was revealed.The test results showed that in the two-step synthesis process，the rod-like magnesium carbonate trihydrate was prepared firstly，which not only improved the filtration efficiency but also greatly reduced the chloride ion entraining rate in the filter cake.Compared with the one-step synthesis process，the chloride ion entraining content in the obtained solid sample was reduced from 6.12% to 2.16%（mass fraction） without using the leach solution.At the same time，the water consumption of the production was only 40% that of the one-step process.The content of MgO and Cl⁻ in the final product met the HG/T 2959—2023 standard of "Industrial hydrated basic magnesium carbonate" and the final yield could reach 97.06%.Therefore，the use of two-step synthesis of basic magnesium carbonate could obviously improve the problem of a large amount of water in the one-step process，and this process could provide an important reference for the preparation of basic magnesium carbonate from the old brine of Qarhan Salt Lake.

In order to solve the problems of slow development of early strength and coarsening of pore structure of traditional fly ash mixed cement mortar，polycarboxylate modified calcium silicate hydrate（C-S-H/PCE） nanocomposites were synthesized by co-precipitation method，and their structures were characterized by various microscopic testing methods.Its effects on the early mechanical properties，pore structure，hydration kinetics and hydration products of cement mortar were deeply explored.The results showed that the addition of C-S-H/PCE could effectively improve the early compressive strength of mortar，and the growth rate of compressive strength was proportional to the content of C-S-H/PCE.When curing age was increased，the growth rate of compressive strength was decreased.C-S-H/PCE could significantly reduce the porosity of mortar samples and reduce the proportion of macropores in mortar，so as to improve the compactness of cement mortar and refine the pore structure.C-S-H/PCE could promote the early hydration of cement paste and improve the early hydration degree of cement paste.The higher the content of C-S-H/PCE，the more obvious the promotion effect.C-S-H/PCE not only effectively promoted the formation of more hydration products of cement and accelerated the whole hydration process，but also this process did not change the composition of hydration products，which ensured the stability and controllability of cement performance.Future research could focus on optimizing the preparation process of C-S-H/PCE，exploring its applicability in different types of cement and admixture systems，and its influence mechanism on the long-term durability of cement-based materials.At the same time，combined with advanced computational simulation technology，the interaction mechanism between C-S-H/PCE nanocomposites and cement matrix was deeply revealed，which provided theoretical basis and technical support for the development of high-performance and long-life cement-based materials.

In order to obtain the industrial production technology conditions for ferric phosphate by using pure iron，Yunnan Yuntianhua Co.，Ltd.，R&D Center after completing the small-scale exploratory experiment and model verification experiment，built a 1 000 t/a pilot plant for ferric phosphate production.The process used high-purity iron ingots（99.9%），purified phosphoric acid（85.0%），and 27.5% hydrogen peroxide as raw materials to produce ferric phosphate by the process of phosphoric acid dissolving iron，hydrogen peroxide oxidizing and precipitating dihydrogen phosphate.The process required the phosphate dihydrogen phosphate solution Fe²⁺ mass fraction to be controlled as the target during the phosphoric acid dissolving process，and the optimized process conditions were as follows：phosphoric acid mass fraction of 26%~27%，dissolving temperature of 88~90 ℃，and dissolving time of 13~15 h.Suggestions were also given for the storage of phosphate dihydrogen phosphate solution.When the mass fraction of the phosphate dihydrogen phosphate Fe²⁺ was controlled at 44~46 g/L and the n（P）∶n（Fe） ratio was（2.65~2.75）∶1，the optimized oxidation precipitation process conditions for producing products with specific surface area as the target were as follows：the initial oxidation temperature of 62~64 ℃，and the hydrogen peroxide feeding time of 50~60 min.The final ferric phosphate product had a P mass fraction of 20.40%~20.70%，Fe mass fraction of 36.18%~36.58%，n（Fe）∶n（P） of （0.970~0.985）∶1，particle size D₅₀ of 3~5 μm，specific surface area of 6~9 m²/g，bulk density greater than 0.60 g/cm³，magnetic impurities controlled below 0.5 mg/kg，and all the indicators met the requirements for battery-grade ferric phosphate.

Lithium-ion batteries（LIBs） play a crucial role in electric vehicles（EVs），high nickel layered metal oxides （LiNi _x Co _y Mn_1-x-y O₂，NCM，x≥0.8） are one of the most important types of cathode materials for lithium-ion batteries.In order to improve the driving range of electric vehicles，increasing the nickel content in NCM cathode material can improve the actual specific discharge capacity of electric vehicles.However，high nickel content leads to structural instability of the cathode material and poor capacity retention ability.The strategy of doping exogenous elements can solve the above problems well.Using the method of solid phase sintering，a strategy of suppressing the volume shrinkage caused by lattice deformation by doping with high price W atoms was studied，while doping inactive Ti atoms to stabilize the rigid frame.This strategy significantly inhibited the concentration of stress，thereby stabilizing the structure，preventing the formation of micro-cracks，and improving electrochemical performance.Due to its unique structural characteristics，the initial capacity at 0.1C was 221.4 mA·h/g，the specific discharge capacity after 200 cycles at 0.5C was 162.9 mA·h/g，and the capacity retention rate was 74.6%.This study provided a new idea for the design of high performance layered cathode materials.

In order to alleviate the problem of phosphogypsum stockpiling pollution and promote the mass utilization of phosphogypsum，sulfuric acid coupled with silane coupling agent was used to further remove impurities and whitening of phosphogypsum after flotation.The results showed that the optimum conditions for the impurity removal and whitening process were as follows：the sulfuric acid mass fraction of 30%，acid leaching solution-solid ratio of 5∶1，acid leaching temperature of 80 ℃，acid leaching time of 30 min，silane coupling agent fraction of 5%，silane coupling agent reaction temperature of 80 ℃ and silane coupling agent reaction time of 60 min.Under this condition，the purification effect was remarkable，and the whiteness of the sample could be increased from 65.19% to 91.91%.In the process of impurity removal and whitening，fluorine and phosphorus impurities were mainly removed by reaction with sulfuric acid.Silicon and organic impurities were mainly adsorbed by the silane coupling agent and aggregated into large particles，which were filtered out.The whiteness and purity of phosphogypsum after impurity removal by this process were close to those of natural gypsum，and its application prospects in related industries such as building materials，papermaking，agriculture，rubber，heat-resistant and reinforced insulation materials were significantly improved，which had certain guiding significance for the realization of the mass utilization of phosphogypsum.

In order to reduce the pollution and damage of drilling production to the surrounding environment，the drilling mud cake was took as the research object，different proportions of slag-based solidification agents were added to solidify the drilling mud cake.The strength of the solidified body and the pH，suspended solids（SS），chromaticity，COD_Cr and other indicators of the leachate were used to evaluate its solidification effect.X-ray diffraction（XRD） and scanning electron microscopy（SEM） were used to reveal its curing mechanism.The results showed that the compressive strength of the solidified body was increased with the increase of solidifying agent dosage and the extension of curing time.When the dosage was 20%，the compressive strength of the solidified body after 7 d was 0.17 MPa，which met the requirements of in-situ paving.When the content was 10% after 7 d，all indicators of the solidified leachate could meet the first level standard in GB 8978—1996“Integrate wastewater discharge standard”，and the solidifying effect of the slag-based solidifying agent was significantly better than that of cement.It was found that the slag-based solidification agent generated hydration products such as hydrated calcium silicate aluminate（C-A-S-H） and hydrated calcium aluminate（C-A-H） through microscopical test，which cemented with mud cake particles to form network structure，making the structure denser.The results of this research could provide some useful guidance and theoretical basis for the disposal of drilling waste mud cake.

Phosphogypsum（PG），a by-product of the phosphate fertilizer industry，has become a significant environmental concern due to improper stockpiling，particularly regarding its potential to release fluoride，which poses a risk to ecosystems.The fluoride leaching characteristics of PG and soil was investigated under different conditions，including leaching time，solid-to-liquid ratio，temperature，and leachant pH.The results showed that fluoride release from PG was significantly higher than from soil，especially under acidic，high solid-to-liquid ratio，and elevated temperature conditions.With increased leaching time，fluoride release from both PG and soil gradually stabilized，with leaching rates reaching approximately 9.9% for PG and 2.0% for soil.As the pH of the leachant increased from acidic（pH=3.03） to near-neutral（pH=6.88），fluoride leaching decreased.Moreover，noticeable changes in the surface morphology of both PG and soil were observed after leaching，with reduced particle size and denser structures.These findings indicated a high potential for fluoride leaching from PG under acid rain and high-temperature conditions，particularly during the summer months with frequent high temperatures and heavy rainfall.The study underscored the importance of effective monitoring and management of PG stockpiles，especially in regions prone to high temperatures and heavy precipitation.

Zinc tailings are harmful industrial wastes.Clean and efficient utilization of zinc tailings not only has important environmental value，but also generates significant economic benefits.In this study，a silicate cement clinker was prepared with sphalerite tailings as additive，and the effect of tailings on the phase composition，microstructure，and hydration performance of clinker was studied.The transfer behavior of Zn²⁺ during the hydration process of clinker was explored.The passivation mechanism of Zn²⁺ leaching activity was also investigated at last.The results showed that the introduction of sphalerite tailings promoted the dissolution of f-CaO into liquid phase，thus accelerating C₃S grain growth.While the synthesis of C₃A phase was prevented after the addition of the sphalerite tailings，because of a reaction occurrence between ZnO and C₃A to generate Ca₁₄Al₁₀Zn₆O₃₅.As a consequence，the 3 d compressive strength of cement slurry was gradually decreased，but the gradual improvements in 7 d and 28 d compressive strengths were present as a function of tailings addition.When 12% sphalerite tailings was introduced.A rubber sand specimen exhibited a 43.49 MPa compressive strength after 28 d curing.The passivation mechanism of Zn²⁺ leaching activity showed that some Zn²⁺ could be solid dissolved in C₃S phase.But most of Zn²⁺ were distributed in the intermediate phase，and it was solidified through the synthesis of anhydrous Ca₁₄Al₁₀Zn₆O₃₅. More over，C₃S containing Zn²⁺ generated hydrated calcium silicate gel after hydration，which could physically wrap the ion and restrain its leaching activity，thus collectively endowing the product with good environmental safety.The research results provided a new approach for the clean and efficient utilization of zinc tailings.

In order to solve the problem of NO accumulation in automobile exhaust gas caused by poor air circulation in the tunnel，resulting in environmental pollution，B-doping nitrogen-rich carbon nitride（B/C₃N₅） composites were prepared by evaporation solvent in-situ thermal polymerization firstly.After B doping，B—N bonds were formed by replacing C atoms instead of replacing N atoms to form B—C bonds.After B doping，the efficient separation of photogenerated carriers was achieved，and the fluorescence lifetime of photogenerated carriers was extended，showing good visible light NO removal activity.The NO removal rate reached 97.36% within 2 h of visible light irradiation.A self-cleaning emulsion was synthesized by using epoxy resin E-44 as a film-forming matrix，B/C₃N₅ composite material as an active center，and low surface energy organic fluorosilicone as a functional monomer.The emulsion was sprayed onto the surface of concrete by spraying method to form a B/CN self-cleaning coating.The coating showed good superhydrophobic and oleophobic properties，and the static water contact angle of the 1.3% B/CN coating reached 160.2°.After 7 d of UV irradiation，the static water contact angle of the coating was still higher than 150° after 30 times of sandpaper abrasion and 15 times of water-oil impact，and the coating showed good durability.The self-cleaning coating showed excellent visible light NO removal activity.After 2 h of visible light irradiation，the 1.3% B/CN coating almost completely removed NO，and the removal rate reached 99.98%.After 5 cycles of use，the NO removal activity was still higher than 96.00%，which was suitable for the degradation of harmful NO gas from automobile exhaust on the inner wall of tunnel concrete.

In order to solve the harm of HCHO gas released by indoor decoration and the problem of resource utilization of waste wind turbine blades，S-doped 2.0% nitrogen-rich carbon nitride（2.0% S-C₃N₅） photocatalyst was prepared by in-situ thermal polymerization using 3-amino-1，2，4-triazole as precursor and thiourea as sulfur source.X-ray diffraction（XRD），Fourier transform infrared spectroscopy（FT-IR），N₂ adsorption-desorption，UV-vis diffuse reflectance spectroscopy（UV-vis DRS），steady-state fluorescence spectroscopy（PL），electron paramagnetic resonance spectroscopy（EPR），transient photocurrent spectroscopy（TPC） and electrochemical impedance spectroscopy（EIS） were used to characterize the phase，group，specific surface area，spectral absorption，photoelectron-hole recombination，defects and electrochemical properties of the photocatalyst.After S doping，the efficient separation of photoelectron-holes and the enhancement of spectral response were achieved，which effectively improved the photocatalytic activity of C₃N₅ and achieved efficient removal of HCHO.The removal rate of HCHO reached 94.97%.The FRP filler concrete prepared by using the glass fiber reinforced resin matrix composite（FRP） after physical crushing of waste wind turbine blades as the reinforcing filler was used as the matrix，and the silicate cement paste doped with 2.0% S-C₃N₅ was used as the photocatalytic coating to construct the FRP reinforced concrete loaded with 2.0% S-C₃N₅ cement coating.The removal rate of HCHO by 2.0% S-C₃N₅ doped 5.0% coating under visible light was 91.05%.The doping of FRP and the coating of 2.0% S-C₃N₅ cement coating significantly improved the mechanical properties of ordinary concrete.Compared with ordinary concrete，the compressive strength and flexural strength of 28 d curing was increased by 18.97% and 20.00%，respectively.