100 results about "Acidity/alkalinity" patented technology

Adhesive compositions including a multivalent metal salt, an multidentate acidic organic compound, and an aqueous medium are disclosed. The multivalent metal salt and multidentate acidic organic compound can include, as a mixture, a carbonate salt and / or carbonic acid. The aqueous medium can include pH adjusting agent such as sodium hydroxide. The adhesive composition, upon curing, can have a porosity of 10-50%. The adhesive composition, upon curing, can include a plurality of pores. The adhesive composition can be porous, and upon curing can have a plurality of pores having a pore size of between 20 μm to 200 μm. Methods of producing the adhesive composition are disclosed. Methods of using the adhesive composition are further disclosed.

The invention relates to the technical field of mineral materials and nano-enzyme catalysis, in particular to an iron-containing layered silicate mineral nano-enzyme as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out ball milling on the iron-containing layered silicate mineral, carrying out centrifugal washing, and drying to obtain the iron-containing layered silicate mineral nano-enzyme. According to the method, silicate minerals with a layered structure and rich iron content are adopted as raw materials, the ball-milled layered silicate mineral nano-enzyme is successfully prepared through a ball milling method, the crystallinity of the minerals is reduced, the surface acidity of the minerals is improved, and low-spin iron is generated, so that the affinity of the ball-milled minerals to H2O2 is enhanced; h2O2 is catalyzed to generate singlet oxygen and superoxide free radicals, so that the peroxidase-like activity of the ball-milled minerals is improved. The enzyme-like activity is improved by 10 times, high catalytic activity can still be kept under the neutral condition, and the method can be used for colorimetric sensing and antibacterial application of small biological molecules such as glucose, hydrogen peroxide and glutathione.

The invention discloses an alcaligenes faecalis UA strain, a product and application thereof, and a method for repairing an acid mine environment by acid-resistant urease-producing bacteria, and belongs to the technical fields of industrial microorganisms, microorganism application materials and environment repairing. The UA strain CGMCC No.33976 is found for the first time to produce the acid-resistant urease, the urease is stably produced in the environment with the optimum acidity of pH 4.5-pH 6.5 and the initial pH of 3.5-pH 7.5, and the enzyme production activity is the highest in the environment with the initial pH of 5.5-pH 6.5. The UA strain can effectively reduce acidity and remove metal ions in water in an acid mine wastewater real water sample, the removal rate of aluminum, manganese, zinc and cadmium exceeds 99%, and the removal rate of calcium, iron and lead is 92%-98%. The UA strain is screened from the acid mine environment, has biological safety, has industrial purposes of AMD in-situ direct treatment and acid mine environment in-situ remediation, does not need to add chemical agents to adjust the pH value of the environment, and has ecological safety and environmental sustainability.

The invention is suitable for the application field of electrolyte acidity determination, and provides a method for determining the acidity of an all-vanadium electrolyte based on a complexing mass difference method, and the method comprises the following steps: taking the all-vanadium electrolyte, and diluting the all-vanadium electrolyte into a pretreated all-vanadium electrolyte with the concentration of 0.05-0.1 mol / L; adding 1.5-2mL of a complexing masking reagent with the molar concentration of 1.5-2mol / L, weighing, and recording as M1; stirring and titrating, weighing and recording as M2; a quantitative determination method of mass difference is used for calculation, and the formula is {(M2-M1)-0.05} / A * C. In conclusion, a mass difference quantitative determination method is adopted, the vanadium complexing masking reagent is added, the adding amount and the pH value of the vanadium complexing masking reagent are controlled, a stable complex is formed through the complexing masking reagent, vanadium ions and impurity ions, the oxidation-reduction reaction and the precipitation reaction of the complex and sodium hydroxide are inhibited, and the accuracy of the acidity value of the all-vanadium electrolyte is improved.

The invention discloses a method for separating and purifying 64Cu in an accelerator irradiation target, which adopts a combined process of an anion column and an extraction resin column to obtain high-concentration and high-purity 64Cu which can be directly used for biomarkers and recover 64Ni at the same time under the condition of not using an organic solvent. The acidity of Cu component effluent in the anion column is similar to that of a column on a Cu resin column, and TK201 resin can be selected to convert the acidity of the Cu component effluent in the Cu resin column and further remove residual Ni in the Cu component effluent in order to solve the problem that the acidity of the Cu component effluent in the Cu resin column is too high. And triple resin columns are superposed, so that a 64Cu final product with higher purity and more appropriate acidity can be obtained.

The invention provides a method for monitoring the acidity of water on line, which comprises the following steps: adding a water sample and a titration indicator into a titration cell, uniformly mixing, measuring the absorbance A background of the water sample mixed with the titration indicator at the wavelength lambda, and taking the absorbance A background as an absorbance background value; titrating the water sample by using a NaOH standard solution as a titrant, and measuring the absorbance A of the water sample at the wavelength lambda in the titration process; taking the moment when the absorbance A is greater than or equal to the absorbance threshold A in the titration process as a titration end point, and obtaining the titration volume of the NaOH standard solution at the titration end point; obtaining the acidity of the water sample based on the titration volume. The method adopts an acid-base indicator titration method to monitor the water acidity and determines the titration end point in combination with the absorbance change of the indicator in the titration process, not only realizes online monitoring of the water acidity, but also is simple and convenient to operate, does not need high-frequency maintenance, can effectively reduce the use cost, improves the water acidity monitoring precision, and is suitable for popularization and application. And application and popularization are facilitated.

The invention discloses a model and a method for predicting sensory acidity by using total acidity and effective acidity, and the method for constructing the prediction model for predicting sensory acidity by using total acidity and effective acidity comprises the following steps: adopting a specified acidic substance as a reference substance; the aqueous solutions of the acidic substances with different concentrations are represented by numerical values of different sensory acidity scales through professional evaluation personnel, and the sensory acidity scales are obtained; the method comprises the following steps: respectively preparing aqueous solutions of different addition amounts of buffer salt, hydrophilic colloid and protein under different concentrations of acidic substances, evaluating the sensory acidity of the aqueous solutions by professional evaluation personnel, and simultaneously detecting the pH value and titration acidity of the aqueous solutions; and performing linear regression analysis by taking the pH value and the titration acidity as independent variables and the sensory acidity as a dependent variable according to the data of the three variables of the sensory acidity, the pH value and the titration acidity in the database to obtain a prediction model. The sensory acidity of the product can be accurately predicted without tasting by sensory personnel.

The invention discloses a high-acidity complex flow state multi-parameter on-line monitoring system, an acid mixing vehicle and a method.The system comprises an acid mixing tank, the acid mixing tank is communicated with a powder pipeline, an acid pipeline, a clear water pipeline, a liquid medicine pipeline and a discharge pipeline, and the powder pipeline, the acid pipeline, the clear water pipeline, the liquid medicine pipeline and the discharge pipeline are all provided with monitoring devices; and the monitoring device is electrically connected with the intelligent control system. The device can record the instantaneous quantity and the cumulant quantity of the acid liquor, the clear water and the chemical additive on line in real time, generate an operation curve and a report at the same time, and can monitor the viscosity, the density and the acidity of the prepared acid liquor on line so as to confirm whether the quality of the acid liquor is qualified or not. According to the invention, monitoring data can be archived, later review and tracing are facilitated, manual sampling analysis is not needed, and potential safety hazards are eliminated.

The invention discloses a method suitable for waste acid purification and acidity improvement in the titanium dioxide industry, and belongs to the field of waste acid treatment. The invention aims at solving the problem of sulfuric acid waste caused by simple treatment of waste acid and solving the technical problems caused by precipitation in the sulfuric acid concentration process. The method comprises the following steps: S1, uniformly mixing cyclohexanol hexaphosphate, phosphate and a flocculating agent according to a certain proportion to obtain a purifying agent; s2, pouring the waste acid accounting for 30% of the total volume of the waste acid into the purifying agent, and stirring; s3, pouring the residual waste acid, and stirring; and S4, then carrying out filter pressing. According to the invention, waste of sulfuric acid caused by a neutralization precipitation method is avoided; the content of metal ions in the activated acid is low, and the problems of regular management and cleaning and equipment maintenance caused by precipitation are effectively avoided during evaporation, concentration and recycling.

This utility model belongs to the field of stainless steel pipe pickling technology, specifically relating to an acid concentration adaptive automatic pickling tank, including a tank body. A perforated plate is fixedly connected to the inner wall of the tank body. An acidity detector is embedded in the tank body. A sealing baffle is detachably connected to the tank body. A disturbance component is arranged below the perforated plate. A reflux component and a vibration component are arranged on the side wall of the tank body. The disturbance component includes a motor, which is fixedly mounted on a mounting frame. A bevel gear is fixedly connected to the output shaft of the motor. This acid concentration adaptive automatic pickling tank, through the use of the disturbance component, uses a motor to drive the agitator blades to rotate, agitating the acid solution. The reflux component, through synchronous transmission, rotates the spiral blades, transporting the acid solution from the bottom of the tank to the top, promoting the circulation and mixing of the upper and lower layers of acid solution, significantly reducing concentration stratification and avoiding excessive or insufficient acid replenishment due to local concentration deviations, thus ensuring stable pickling results.

The invention discloses an amide ether type hydroxamic acid compound and a preparation method and application thereof, the chemical structural formula of the amide ether type hydroxamic acid compound is as shown in formula I. In the formula I, R1 and R2 are independently selected from C1-C12 carbon chains; x is selected from O or S. The invention designs and synthesizes a novel hydroximic acid with an amide ether structure, and the amide ether type hydroximic acid compound can be widely applied to extraction and flotation of metal elements such as rare earth, zirconium, hafnium, cobalt, nickel and the like. The amide ether type hydroximic acid compound as an extracting agent has the advantages of high separation coefficient, no generation of highly toxic substances such as HSCN, wide extraction acidity range, large saturation capacity, capability of realizing complete reverse extraction by using relatively low-concentration sulfuric acid, and the like. # imgabs0 # formula I

The present invention discloses a method for preparing N-hydroxysuccinimide. The method uses a weakly acidic cation exchange resin as a catalyst. By reducing the acidity of the reaction system, product decomposition can be avoided, thereby improving product yield and quality. The method also reduces the reaction temperature, lowers equipment anti-corrosion requirements, extends equipment service life, reduces energy consumption, and is more conducive to industrial implementation. Furthermore, the catalyst is recyclable and does not require the addition of a stabilizer, making it more environmentally friendly.

The present invention belongs to the acidification process, and particularly relates to a separate acidification process for a weakly confined mining area in an acid-in-situ leaching mine. A separate acidification process for a weakly confined mining area in an acid-in-situ leaching mine, which includes the following steps: the first step: pumping and injecting clear water in a cycle; the second step: low-acid acidification; the third step: high-acid acidification; the fourth step: integrally connecting to the production system. The remarkable effects of the present invention are as follows: (1) During the acidification of a single mining area, the acidity of the leaching agent in the mining area can be flexibly adjusted. (2) Filtration of the extracted liquid during the acidification cycle stage is achieved, reducing the probability of secondary blockage caused by clay impurities entering the ore layer. (3) By adding clear water, the injection volume of the acidification leaching agent is increased, while the acidification intensity is enhanced and the groundwater level in the weakly confined mining area is raised. (4) When the uranium concentration in the extracted liquid of a single well reaches the design index, it can be connected to the production system at any time, and other pumping and injection units continue to cycle and acidify.

The invention discloses a metal-doped VOOH nano-enzyme material with a hollow spherical shell structure as well as a preparation method and application of the metal-doped VOOH nano-enzyme material, and belongs to the technical field of nano-materials and biological catalysis. The invention aims to solve the problems that the peroxidase-like activity of the existing pure-phase VOOH nano material is relatively limited, the electronic structure of the pure-phase VOOH nano material is not in the optimal state of catalyzing H2O2 decomposition, and the adsorption / desorption energy barrier of a reaction intermediate is relatively high. The chemical general formula of the metal-doped VOOH nano-enzyme material with the hollow spherical shell structure is M-VOOH, and M is a doped metal element. The preparation method comprises the following steps: 1, dissolving a precursor; 2, acidity adjustment; 3, doping metal; and 4, reduction and crystallization. According to the application, the catalyst serves as a peroxidase-like catalyst to catalyze decomposition of hydrogen peroxide.

The present invention discloses the UA strain of Alcaligenes faecalis, its products and applications, and a method for remediating acidic mine environments using acid-resistant urease-producing bacteria. These strains belong to the fields of industrial microorganisms, microbial application materials, and environmental remediation. The UA strain, CGMCC No. 33976, is the first acid-resistant urease-producing bacteria discovered. Its optimal acidity lies between pH 4.5 and pH 6.5, with stable urease production at an initial pH of 3.5 to pH 7.5 and highest enzyme activity at an initial pH of 5.5 to pH 6.5. In real samples of acidic mine wastewater, the UA strain effectively reduces acidity and removes metal ions, achieving removal rates exceeding 99% for aluminum, manganese, zinc, and cadmium, and 92% to 98% for calcium, iron, and lead. The UA strain, screened from acidic mine environments, exhibits biosafety and is suitable for in-situ direct treatment of AMD and in-situ remediation of acidic mine environments. It eliminates the need for chemical pH adjustment, ensuring ecological safety and environmental sustainability.

The invention provides a method for jointly detecting chromium and vanadium contents in high alloy steel, which comprises the following steps: dissolving and heating an alloy steel sample by using sulfuric acid and nitric acid to obtain a to-be-detected alloy sample; adding strong phosphoric acid and ammonium persulfate into the to-be-tested sample, boiling, cooling, dropwise adding an indicator, titrating to obtain a solution after vanadium titration, recording the volume of the solution adopted for titration, and calculating to obtain the vanadium content in the to-be-tested alloy sample; and diluting the solution after vanadium titration, adding silver nitrate and ammonium persulfate, boiling, heating, cooling, dropwise adding an indicator, titrating, recording the volume of the solution for titration, and calculating to obtain the chromium content in the alloy sample to be detected. According to the method, the acidity of the system is controlled by adjusting the addition amount of sulfuric acid and concentrated phosphoric acid, no extra catalyst is needed to oxidize chromium, other metals in a sample are not oxidized, and the vanadium element and the chromium element in the high alloy steel can be detected.

The standard substance for simulating the acidity of the product oil comprises benzoic acid and low-carbon alcohol, the purity of the benzoic acid is not lower than 99.8 wt%, and the low-carbon alcohol is one of methanol, ethanol or propanol; the concentration of the standard substance is 1 to 10 mgKOH / 100 mL, preferably 2 to 7 mgKOH / 100 mL. The acidity standard substance is good in accuracy, fills the blank that no acidity standard substance exists at present, and has wide application prospects in the aspects of calibration of a petroleum product acidity tester, confirmation of an acidity measuring method, instrument quality control and the like.

The present invention relates to a reforming catalyst comprising: - a porous support comprising essentially alumina; - platinum in a content comprised between 0.2 and 0.6% by weight; - at least one VA group element chosen from antimony, bismuth and phosphorus, in a content comprised between 0.2 and 0.8% by weight; - at least one IA group element chosen from lithium, sodium and potassium, in a content comprised between 0.004 and 0.2% by weight; - at least one IIIA group element chosen from gallium, indium and thallium, in a content comprised between 0.02 and 0.6% by weight.

The invention discloses a method for efficiently reducing elemental selenium from selenium-containing leachate based on ferrous sulfate, which comprises the following steps: taking the selenium-containing leachate obtained by oxidation and acid leaching, and adjusting the acidity of the leachate to 0.5-1.1 mol / L; ferrous sulfate is added into the acid-adjusted selenium-containing leachate according to the liquid-solid ratio of 2 mL: (1.0-1.4) g for a reduction reaction, the reduction reaction temperature ranges from 70 DEG C to 90 DEG C, the reduction reaction time ranges from 40 min to 80 min, and a reaction product I is obtained; and separating the precipitate of the reaction product I, washing and drying to obtain the elemental selenium. According to the method disclosed by the invention, the elemental selenium is extracted by reducing the selenium-containing leachate by adopting ferrous sulfate, and the reduction rate of selenium can reach 91% or above under limited conditions; under optimized conditions, the selenium reduction rate can reach 95.87%, which is significantly superior to that of existing processes such as a microbiological method.

The invention discloses an acidity detection device for electronic-grade fluorocarbon gas and a use method of the acidity detection device. The detection device comprises an absorption detection unit, an absorption liquid supplementing unit, a detection liquid supplementing unit and a control unit, the absorption detection unit comprises two absorption bottles, the first absorption bottle is connected with the second absorption bottle in series, a pipeline from gas to be detected is inserted into the first absorption bottle, a first gas distributor is arranged at the insertion end, and a second gas distributor is arranged at the bottom end of the pipeline from the first absorption bottle to the second absorption bottle; the absorption liquid supplementing unit comprises an alkali liquid storage tank and a first peristaltic pump; the detection liquid supplementing unit comprises an acid standard solution storage tank and a second peristaltic pump; the control unit comprises three pH meters which are respectively used for detecting the pH value of the liquid in the first absorption bottle, the pH value of the liquid in the second absorption bottle and the pH value of the acid standard solution. The acidity detection device and the detection method are high in automation degree, can be used for detecting fluorocarbon gas with the acidity content of 0.01 ppm or below, and are high in accuracy.

The utility model discloses a copper-containing waste liquid treatment acidity adjusting device which comprises a treatment box, an acid-base controller and water pumps, the acid-base controller is fixedly installed on the surface of one side of the treatment box, the water pumps are fixedly installed on the upper surface of the treatment box and close to the two sides of the rear portion, and a base is fixedly installed on the rear surface of the treatment box and located at the lower end. And liquid storage barrels are arranged on the upper surface, close to the two sides, of the base, the surfaces of the liquid storage barrels are sleeved with limiting frames, and a box cover is arranged on the upper surface of the treatment box. According to the acidity adjusting device for copper-containing waste liquid treatment, when the liquid storage barrel is replaced, the lifting motor can control the limiting frame to descend, so that the lantern ring of the limiting frame is embedded into the annular groove of the base, the lantern ring does not need to be detached, and when a new liquid storage barrel is placed at a designated position, the arc-shaped plate can be pressed down by the liquid storage barrel, so that the liquid storage barrel is replaced. The liquid storage barrel can be rapidly placed at a designated position under the action of the arc-shaped plate and does not need to be adjusted many times.

A ware washing machine includes a chamber for receiving a ware, the chamber having at least one spray zone in which liquid can be recirculated from a tank to a spray assembly for spraying the liquid onto the ware. The decalcification system is configured to deliver a decalcification solution to the tank. The controller is configured to operate in at least one vessel cleaning mode and at least one calcium removal mode of operation. The controller is configured such that, in a calcium removal mode of operation, the calcium removal system is controlled to perform a calcium removal operation wherein the controller (i) controls the calcium removal system to deliver the calcium removal solution into the tank and (ii) performs an acidity reduction process to reduce the acidity of the calcium removal solution.

The invention is applicable to the technical field of electrochemical analysis, and provides a method for measuring the acidity of an iron-chromium electrolyte based on a complexing mass difference method.The method comprises the following steps that a pretreated iron-chromium electrolyte is prepared, a complexing reagent playing a complexing role on iron and chromium ions is added into the pretreated iron-chromium electrolyte, and the weight is recorded as M1; the pretreated iron-chromium electrolyte added with the complexing reagent is stirred, then a standard alkali solution is dropwise added, after titration is stopped, the weight is weighed and recorded as M2, a quantitative determination method of mass difference is used for calculation, and the acidity calculation formula is {(M2-M1)-K} * C. In conclusion, a quantitative determination method for the quality difference is adopted, and the complexing reagent containing carboxyl is added, so that the side reaction of iron and chromium ions is reduced and avoided, the selectivity and the accuracy of determining the acidity of the iron-chromium electrolyte are improved, and the rapid and accurate determination of the free acid is realized.

The invention relates to a method for separating material components in nonferrous metallurgy, in particular to a method for separating indium and tin from a high-acidity indium and tin mixed solution. The method comprises the following steps: taking a certain amount of indium-tin mixed solution, firstly adding a certain amount of arsenic-containing detinning agent into the indium-tin mixed solution, then adding a sufficient amount of oxidant, carrying out arsenic and tin co-precipitation reaction, and after the reaction is finished, filtering to obtain detinned slag and detinned liquid. On the basis of the principle of arsenic and tin co-precipitation reaction, tin is separated from the high-acidity indium-tin mixed solution by adopting the arsenic-containing detinning agent, the highest detinning rate can reach 99% or above, indium is reserved in the solution, the loss is 5% or below, and the purpose of separating indium and tin in the solution is achieved. The method is short in technological process, easy to operate, good in indium and tin separation effect, low in cost and easy to apply in an engineering mode.

Process for the rejuvenation of a catalyst comprising a metal from group VIII, a metal from group VIb and an oxide support not comprising zeolite, comprising the following stages:a) said catalyst is regenerated at a temperature of between 360° C. and less than 420° C. so as to obtain a regenerated catalyst comprising a certain content of carbon and sulfur and a proportion of crystalline phase determined by X-ray diffraction and characterized by a ratio of less than 0.6,b) said regenerated catalyst is brought into contact with an aqueous solution consisting of water, of phosphoric acid and of an organic acid having each acidity constant pKa greater than 1.5,c) drying is carried out at a temperature of less than 200° C.

The invention discloses a method for rapidly synthesizing an acidity-adjustable ZEO-1 molecular sieve, and belongs to the field of molecular sieve synthesis. According to the method, a seed crystal and an additional cationic auxiliary agent are introduced into a ZEO-1 molecular sieve synthesis system, and under the synergistic effect of the seed crystal and the auxiliary agent, rapid crystallization synthesis and wide-range acidity adjustment of the ZEO-1 molecular sieve under the condition of extremely low template agent dosage can be realized. According to the present invention, the synthesis process is efficient, simple and convenient, the ZEO-1 molecular sieve can be rapidly synthesized under the alkaline condition (taking OH <-> as the mineralizer) or the neutral condition (taking F <-> as the mineralizer), the ZEO-1 molecular sieve obtained through the method has characteristics of good crystallinity and high thermal stability, and the silicon-aluminum or silicon-boron atomic ratio can be adjusted in the large range of 4-200.

The present application relates to the technical field of computer, and provide a kind of water regulating method and system, the method comprises: obtaining turbidity sensor value and acid-base sensor value;Based on turbidity sensor value and acid-base sensor value respectively fuzzy operation, obtain turbidity fuzzy set and acidity fuzzy set;Based on turbidity fuzzy set and acidity fuzzy set, determine the incoming water credibility set, and based on incoming water credibility set and preset fuzzy control table, determine first credibility output;Based on first credibility output, determine target new incoming water flow, and with target new incoming water flow control new incoming water flow into water regulating system.The water regulating method provided in the embodiment of the present application is in the process of water regulating, according to turbidity sensor value and acid-base sensor value, fuzzy control operation is carried out, target new incoming water flow is determined, so as to control the amount of water flowing into water regulating system according to target new incoming water flow scientifically and accurately, so as to reduce water consumption, realize energy saving and emission reduction.

The invention discloses a rapid online detection method for the content of residual acid in a multi-element metal salt solution and application of the rapid online detection method. The method comprises the following steps: preparing an alkali standard solution, and determining the titer of the alkali standard solution to the residual acid; the method comprises the following steps: preparing a pH meter, carrying out two-point correction on the pH meter, preparing a multi-element metal salt standard solution, dropwise adding an alkali standard solution in a stirring state, detecting the pH by using the corrected pH meter, recording the consumption of the alkali standard solution when the titration end point is reached, and calculating to obtain the content of the residual acid in the multi-element metal salt standard solution. According to the method, the pH value of metal ions which are firstly precipitated in a multi-element metal salt standard solution is taken as a titration key pH value, so that the problem that the acidity of a detection result is relatively high due to the fact that the metal salt ions which are easy to hydrolyze consume hydroxyl radicals in a precipitation process is avoided, and tests show that the relative error between the residual acid content measured by the method and a theoretical value is less than or equal to 2%, and the relative error is less than or equal to 2%. And the detection period is shortened to 5-10 minutes, so that the requirements of online detection on detection precision and speed can be met.

The micromolecule Raman pH probe provided by the invention has relatively strong sensitivity and an adjustable pH response range, can be anchored at an interface with relatively low loading capacity, realizes accurate measurement of interfacial acidity, is especially suitable for interfacial acidity measurement of a colored interface, and has a wide application range.

The invention provides a method for improving the phosphating color difference of a manganese alloy steel product, which comprises the following steps in sequence: alkaline washing: adopting an alkaline solution with the pH value of 13-14, the alkaline washing temperature of 110-140 DEG C and the alkaline washing time of 30-35 min; first flowing water washing; acid pickling is conducted, an acid solution with the free acidity being 80-270 is adopted for acid pickling, the acid pickling temperature is 15-25 DEG C, and the acid pickling time is 1-2 min; and second flowing water washing. According to the method, the surface of the workpiece is treated through the aqueous alkali before the workpiece is subjected to manganese phosphating treatment, metal iron on the surface of the workpiece reacts with the aqueous alkali, the black alkaline ferroferric oxide protective film is generated, the protective film is black, the problem of color difference on the surface of the gear workpiece is solved, and the service life of the gear workpiece is prolonged. And the gear workpiece is more wear-resistant and corrosion-resistant.