Platinum and its composite powder are widely used in electronic information, energy, automotive and other high-end manufacturing fields, due to its unique performance. With the high-quality and rapid development of Chinese advanced equipment manufacturing industry, higher requirements are put forward for the performance of platinum and its composite powder, and the demand for dosage is increasing. In this paper, the most widely used liquid phase method for preparing platinum and its composite powder at home and abroad is reviewed. The research progress of sol-gel method, hydrothermal method, microemulsion method and liquid phase chemical reduction method for preparing platinum and its composite powder is summarized, and the advantages and problems of various method in the process of preparing precious metal powder are also summarized. The development direction of efficient preparation of platinum and other precious metals ultrafine powders is prospected.

The influence of fluorine on the production wet-process phosphoric acid is described. The principle, application status, advantages and disadvantages of the main defluorination process of wet phosphoric acid are reviewed. The problems existing in the current defluorination process of wet phosphoric acid are pointed out, and the future development direction is put forward in order to provide reference for the comprehensive utilization of fluorine resources in wet phosphoric acid in our country.

The comprehensive recovery of copper and arsenic from black copper slime by oxidation leaching method was studied. The effects of acidity, hydrogen peroxide content, temperature, leaching time and liquid volume to solid mass ratio on the leaching rate of copper and arsenic were investigated. The results show that under the conditions of acidity of 200 g/L, hydrogen peroxide content of 30%, temperature of 80 ℃, leaching time of 2.0 h, liquid volume to solid mass ratio of 9∶1, the leaching rates of copper and arsenic can reach 99.53% and 98.24%, respectively. After oxidative acid leaching, sodium hydrosulfide is added into the solution at the rate of n(NaHS)/n(Cu)=1.1 to precipitate copper. The mass concentration of copper in the solution after copper and arsenic separation is lower than 0.01 g/L, and the mass concentration of arsenic is greater than 40 g/L. The copper and arsenic are effectively separated. Arsenic-rich liquid can be reduced with sulfur dioxide, and arsenic trioxide and reduced liquid can be returned to the oxidation leaching process.

The change of iron grade in the leaching residue and the leaching kinetics under normal pressure and pressure were examined. The pressure leaching of nickel and cobalt from a high iron and low grade laterite nickel ore in Indonesia with sulfuric acid was studied. The results show that under the conditions of acid/ore ratio of 260 kg/t, leaching temperature of 250 ℃ (corresponding to water vapor pressure of 4.0 MPa), liquid volume/solid mass ratio of 3/1, stirring speed of 300 r/min, particle size of 100 mesh and reaction time of 1 h, the leaching rates of nickel, cobalt and iron are 98.1%, 98.3% and 4.7%, respectively, and the iron grade can reach 51.3%. The leaching processes of nickel and cobalt under pressure and atmospheric pressure are in line with the shrinkage kernel model of interfacial chemical reaction control, and the activation energies of the reactions are 116 kJ/mol and 91 kJ/mol under pressure, respectively, and the activation energies of the reaction under atmospheric pressure are 41 kJ/mol and 53 kJ/mol, respectively. The leaching is mainly goethite under normal pressure, and chromite, magnetite and other mineral phases under high pressure.

In order to realize the high value utilization of solid and liquid wastes, extraction of vanadium from vanadium tailings with titanium dioxide waste acid was studied. The effects of leaching temperature, leaching time, solid mass to liquid volume ratio, waste acid concentration and other technological parameters on vanadium leaching rate were investigated by orthogonal experiments, and the optimal leaching conditions were determined. In order to further improve the vanadium leaching rate, the appropriate amount of leaching aid (fluorite) and oxidant (hydrogen peroxide) was discussed. The results show that the order of influence of the process parameters on vanadium leaching rate is leaching temperature> leaching time> solid mass to liquid volume ratio> titanium dioxide waste acid concentration. Under the optimum conditions of temperature of 80 ℃, leaching time of 2 h, solid mass to liquid volume ratio of 1∶5 and waste acid concentration of 5%, the vanadium leaching rate is about 53%. After adding 7% fluorite and 5% hydrogen peroxide, the vanadium leaching rate can be increased to 71.09%.

In order to promote the recovery and utilization of valuable resources in steel slag, the leaching behavior of each element in converter steel slag in mixed acid (citric acid+nitric acid) system was studied. The effects of mixed acid concentration, reaction time, reaction temperature, liquid volume to solid mass ratio, and slag particle size on the leaching rate of each valuable element were examined. The results show that acid concentration, reaction time, liquid volume to solid mass ratio, and slag particle size have significant impact on the leaching rate of calcium, magnesium, iron, manganese and phosphorus. The reaction temperature has little effect on the leaching rate of each element. Under the conditions of steel slag particle size of 65 μm, leaching temperature of 298 K, leaching time of 30 min, liquid volume to solid mass ratio of 300∶1 and stirring speed of 800 r/min, the leaching rate of phosphorus is 88.15% with 0.01 mol/L nitric acid and 20.8 mmol/L citric acid. And effective leaching of phosphorus is obtained.

The leaching of manganese from electrolytic manganese residue with sulfuric acid was studied, and the process parameters were optimized by single factor test and orthogonal test. The phase, structure, morphology and leaching kinetics of electrolytic manganese residue before and after leaching were analyzed. The leaching model was established and the leaching mechanism was explored. The results show that under the optimal conditions of particle size of 200 mesh, stirring speed of 400 r/min, leaching temperature of 95 ℃, sulfuric acid concentration of 1.5 mol/L, leaching time of 120 min and liquid volume/solid mass ratio of 11/1, the leaching rate of Mn can reach 97.90%. Manganese leaching kinetics accords with the liquid-solid shrinkage model and is controlled by chemical reaction. In the process of manganese leaching, the leaching rate of Mn can be improved by controlling the liquid volume/solid mass ratio and temperature.

The leaching of molybdenum from molybdenite by oxygen pressure water leaching method was studied.The effects of ore size, oxygen partial pressure, temperature and stirring speed on oxidation of molybdenite were investigated, and the distribution of oxidation products in solid and liquid phases was discussed. The results show that the oxidation of molybdenite can be promoted by the decrease of ore particle size and the increase of oxygen partial pressure, temperature and stirring speed. The oxidation products first enter the liquid phase. When the liquid phase is saturated with $\mathrm{MoO}_{4}^{2-}$, the oxidation products will enter the slag phase in the form of MoO₃. The oxidation of molybdenum during oxygen pressure water leaching of molybdenite can be described by the unreacted nuclear shrinkage model.The reaction rate is controlled by the mixed control model, and the apparent activation energy is 40.55 kJ/mol.

The effects of solution coordination environment on the extraction of vanadium by P204 were investigated. The effects of chloride, fluoride and sulfate ions on the extraction of vanadium and their coordination with vanadium were examined at different pH. The results show that for the extractant using an organic phase composition of 20%P204+5%TBP+75%sulfonated kerosene, at phase ratio of V_O/V_A=1/2 and extraction time of 8 min, chloride ions can effectively enhance vanadium extraction. At pH=1.0 and [Cl^-]=5 mol/L, the vanadium extraction can reach 87.93%. When the pH is 1.4~2.2, fluoride ions in a certain concentration range can promote the extraction, and the best promotion effect is achieved when [F^-]=0.05 mol/L. The concentration of fluoride ion is greater than 0.2 mol/L, and the extraction is inhibited. When pH=1.8 and 2.2, the concentration of sulfate has little effect on vanadium extraction. But when pH=1.0 and [$\mathrm{SO}_{4}^{2-}$]=1.5 mol/L, the vanadium extraction rate is only 52.22%, and the high concentration of sulfate can significantly inhibit vanadium extraction. The thermodynamic results show that coordination groups VOCl⁺ and VOF⁺ can enhance vanadium extraction process. When the concentration of fluoride ion is higher than 0.2 mol/L, the coordination anion VOF₃ formed by VO²⁺ and multiple F^- prevents the cation exchange reaction of P204.

The separation and enrichment of precious metal gold in chloride system with synergistic extraction system composed of DIBK (HA) and TBP (B) was stuied. The effects of extraction system and composition, extraction time, extraction temperature, aqueous chloride ion concentration,and extraction ratio (V_O/V_A) on the separation performance of gold extraction was investigated, and the extraction mechanism was preliminarily explored by slope method. The results indicate that under the conditions of synergistic extraction system of TBP-DIBK, total extractant concentration of 1.5 mol/L, n(TBP)∶n(DIBK)=1∶4, extraction time of 20 min,extraction temperature of 20 ℃, V_O/V_A= 2/1, aqueous chloride ion concentration of 6 mol/L, the extraction rate of gold can reach 98.82%.The maximum gold/copper extraction separation coefficient is 1 189.05. Gradient method suggests that the composition of the extract may be [AuCl₆·3A·B]. The extraction chemical reaction formula can be rewritten as: Au³⁺+6Cl^-+3HA+B→[AuCl₆·3A·B]+3H⁺.

The extraction and separation of ferrum and copper from waste ternary cathode material by Cyanex 302 (the main component is di (2,4,4-trimethylamyl) monothiophosphoric acid) was studied. The effects of H⁺ concentration, extractor concentration and temperature on the extraction and separation performance of Cyanex 302 were investigated. And the technological conditions for the stripping of ferrum and copper in supported organic phase were determined. The process flow of extracting ferrum and copper from waste ternary cathode material leaching solution is designed. The results show that the optimal extraction conditions are 0.1 mol/L Cyanex 302 concentration, 0.1 mol/L H⁺ concentration, room temperature.Under these conditions, the extraction rates of ferrum and copper are over 99.9%, while the extraction rates of Ni(Ⅱ), Co(Ⅱ), Mn(Ⅱ), and Li(Ⅱ) are all below 0.003%. The optimal stripping agent for ferrum is 1 mol/L H₂SO₄, and that for copper is 1.5 mol/L HNO₃.The process can effectively separate copper and ferrum from the leaching solution.

The desorption of tungsten and molybdenum from ZGA351 porous strong basic anion exchange resin using NaOH+NaNO₃ as desorption agent and H₂O₂ as strong oxidant was studied. The effects of combined adsorbent composition,concentration of NaOH, concentration of NaNO₃, concentration and dosage of H₂O₂, flow rate ratio of NaOH+NaNO₃/H₂O₂ and desorption times on the desorption of tungsten and molybdenum were investigated. The results show that under the conditions of NaOH concentration of 1.5 mol/L, NaNO₃ concentration of 5%, H₂O₂ addition of 1.2 times the theoretical doasge, H₂O₂ concentration of 30%, the NaOH+NaNO₃/H₂O₂ flow rate of 40 for 6 times, the tungsten and molybdenum desorption rate are 99.48% and 99.38%, respectively. The molybdenum penetration adsorption capacity of the resin is 107.10 g/L, which is similar to that of the new resin 107.77 g/L, indicating that the adsorption properties of ZGA351 resin remained basically unchanged after one desorption and cyclic adsorption. The mass concentration of tungsten in the primary desorption solution is 3.82 g/L, the mass concentration of molybdenum is 10.71 g/L, and the ratio of molybdenum to tungsten is 2.80. After adjusting the acid, it can be directly put into the subsequent industrial production section to make ammonium molybdate products. The results of 30 desorption and adsorption cycles show that the service life of the resin can meet the requirements of industrial production cost. The method synchronizes the process of liquid absorption oxygenation and resin regeneration.The process is simplified, the production cost is reduced, and a feasible process route is explored for the desorption process of large pore strong basic anion exchange resin.

The removal of Mo(Ⅵ) from wastewater was studied by using jarosite after iron deposition in zinc leaching solution as adsorption material. The effects of the initial pH of simulated wastewater, the initial mass concentration of Mo(Ⅵ), the additon amount of jarosite and the adsorption time on the adsorption of Mo(Ⅵ) by jarosite were investigated, and the kinetic mechanism of the adsorption process was discussed. The results show that under the conditions of initial mass concentration of Mo(Ⅵ) of 40 mg/L, pH=3.0, additon amount of jarosite of 1.0 g/L and adsorption time of 240 min, the adsorption capacity of Mo(Ⅵ) can reach 13.21 mg/g. The adsorption process of Mo(Ⅵ) in wastewater by jarosite is more suitable to be described by quasi-second-order kinetic model, which belongs to chemical adsorption. The adsorption process of molybdenum by jarosite follows the Langmuir isothermal adsorption model and has higher fitting accuracy. The adsorption process belongs to monolayer molecular adsorption. This method has the advantages of simple process and low cost, and is expected to realize high-value recycling of waste residue.

The adsorption and desorption properties of MTA1701 and RCX5143 macroporous weak basic anionic resins for rhenium recovery in arsenic reduction solution were studied. The effects of pretreatment method, time,temperature,acidity and equilibrium concentration on adsorption of rhenium using resin were investigated by static adsorption. Static desorption of ammonia water was used to investigate the effects of ammonia concentration, desorption volume ratio, desorption time and desorption times on the desorption rate of supported resin. The results show that the properties of the two resins are similar, and the adsorption reaction of the resin is in accordance with the quasi-second-order reaction kinetics model after the pretreatment of sulfuric acid soaking. The thermodynamic results show that decreasing temperature is beneficial to the adsorption of rhenium. The static equilibrium adsorption capacity decreased with the increase of acidity and increased with the increase of equilibrium concentration. Under the conditions of ammonia concentration of 10%, V(ammonia)∶V(resin) of 2∶1, desorption time of 20 min for 2 times desorption, the desorption rates of the two resins are all greater than 99.5%.

The preparation of activated carbon from coffee grounds by activated roasting coffee grounds with NaOH and the adsorption and removal of Cu(Ⅱ) from wastewater containing copper were studied. The activated carbon of coffee grounds was characterized by SEM and EDS. The effects of initial pH of wastewater, initial mass concentration of Cu(Ⅱ), adsorption time and amounts of adsorbent on the adsorption of Cu(Ⅱ) were investigated. The results show that for the 50 mL simulated copper-containning wastewater with mass concentration of 50 mg/L and pH=6, under the optimal conditions of activated carbon from coffee grounds amounts of 10 mg, temperature of 25 ℃ and stirring speed of 150 r/min and adsorption time of 9 h, the Cu(Ⅱ) adsorption removal rate can reach 94.12%. Langmuir isothermal adsorption model and quasi-second-order kinetic model can describe the adsorption process well. The adsorption performance of Cu(Ⅱ) in wastewater is good.

Chitosan microspheres (HTCC) were prepared by hydrothermal method, and Amino-modified chitosan adsorbent (AHTCC) was prepared by epoxidization and amination method to adsorb low concentration uranium in wastewater. The structure, composition and thermal stability of AHTCC were characterized by infrared spectrometer, elemental analyzer and thermogravimetric analyzer, and the adsorption and desorption properties of AHTCC for uranium were investigated. The results show that AHTCC has a good adsorption effect on uranium in solution at pH=5~8. Under the condition of equilibrium mass concentration of uranium adsorption of 120 mg/L, the adsorption capacity reaches the 151.6 mg/g. Its adsorption rate is faster in the initial 60 min and reaches equilibrium at 180 min. Using 80 g/L Na₂CO₃+20 g/L NaHCO₃ as the desorption agent, the desorption rate of uranium is 97.5%. For real uranium containing wastewater with high concentration of impurities, the removal rate of uranium can reach 95.6% after single adsorption by AHTCC.

Gallium, indium, cadmium, selenium, tellurium, germanium, thallium and other rare disperse elements are often present in copper deposits, and accurate analysis of these elements is beneficial to comprehensive utilization of minerals. The determination of Ga, Ge, In, Tl, Se, Te and Cd in copper ore by microwave digestion and inductively coupled plasma mass spectrometry was established. The symmetric sample size, acid system, ethanol concentration, microwave digestion work conditions and mass spectrum interference were optimized. The results show that under optimized conditions, the linear correlation coefficient of the calibration curve is greater than 0.999 5, and the detection limit is 0.002~0.19 μg/g. The relative standard deviations (RSD, n=6) are 2.63%~13.84%, and the standard recoveries are 90.4%~110.6%. The method is accurate and reliable, and the results are consistent with the standard method.