72results about How to "Reduce containing" patented technology

The present invention concerns an anaerobic digestion of animal manures, energy crops and similar organic substrates. The process is capable of refining nutrients comprised in the digested biomass to fertilizers of commercial quality. The invention also provides a method for processing animal carcasses or fractions thereof including meat and bone meal etc., with the objective of providing an alternative means for processing the organic waste material of animal origin while at the same time facilitating the production of fertilizers. The risk of spreading BSE prions or any other prions to animals or humans is thus substantially reduced if not eliminated. The biogas and slurry separation system according to the present ivnention is preferably integrated with the operations of animal husbandries into a total concept in which the internal and external performances of animal husbandries are optimised. The internal performances concern quality aspects related to the management of the animalhouses and include industrial hygiene, animal welfare, gaseous and dust emissions and food safety. The external performances concern mainly energy production and emissions to the environment of nutrients and greenhouse gases and the sale of high quality food product.

The invention discloses an aluminum-plated propylene and butylene co-polypropylene tape casting membrane material. The preparation raw materials include polypropylene resin, an antioxidant and a halogen absorbent, wherein the polypropylene resin is propylene and butylene co-polypropylene resin and is prepared by adopting the following method: by taking propylene as a raw material and 1-butene as a copolymerization monomer, copolymerizing in a circular tube reactor to obtain propylene and butylene co-polypropylene resin, wherein the reaction temperature is at 70+ / -1DEG C, the reaction pressure is under 3.4-3.8MPa, the concentration of hydrogen is 800-1500ppm, and the concentration of 1-butene is 1%-5%. The invention further discloses a preparation method of the tape casting membrane material. An aluminum-plated tape casting membrane prepared by the tape casting membrane material has good processability, optical performance, mechanical performance and aluminum plating performance, and the production requirement of a tape casting membrane packaging factory on the aluminum-plated tape casting membrane can be met.

The invention relates to a method for manufacturing a fermented liquid fertilizer containing less heavy metal by using effective microorganisms. The fermented liquid fertilizer containing less heavy metal is characterized by using the effective microorganisms manufactured by the above method. A composition for reducing the heavy metal of the fermented liquid fertilizer is characterized by comprising an effective microorganism culture solution as an effective component. The effective microorganism culture solution has an excellent heavy metal removal effect so as to be used for reducint the heavy metal in the soil and water. In addition, the invention can provide a liquid fertilizer capable of cultivating crops environmentally friendlily instead of pesticides and chemical fertilizers. The liquid fertilizer has characterisitcs of removing the odor of livestock fecaluria in a composting process so as to be diluted and sprayed by water anytime and to reduce the heavy metal in the livestock fecaluria.

The invention discloses a screening device for cosmetic powdery raw material production, and relates to the technical field of cosmetic production equipment. The device comprises a box body, supporting legs, a feeding pipe and a discharging pipe, wherein the supporting legs are fixed to four corners of the lower surface of the box body, the feeding pipe is inserted into one side of the upper sidewall of the box body, the discharging pipe is inserted into the lower side of one side wall of the box body, a door body is embedded into the front side wall of the box body, one side of the door bodyis rotationally connected to one side of the box body through a hinge, and the other side of the door body is connected to the other side of the front side wall of the box body through a cross lock;the device further comprises a grinding mechanism and a filtering mechanism, wherein the grinding mechanism is arranged on the upper side inside the box body, the filtering mechanism is arranged on the lower side of the grinding mechanism, and a filtering pool in the filtering mechanism is suspended in the center inside the box body; and before filtering, lumps in powdery raw materials can be ground, the lump materials contained in the raw materials are reduced, the efficiency is improved, and the device has the advantages of being reasonable in arrangement, low in manufacturing cost and the like.

The invention discloses an urban sewage treatment reclaimed water circulating filtration device. The device includes a water circulation filter box, a control switch is embedded and installed at one end of the water circulation filter box, the top of the control switch is rotatably connected to a protective cover plate, and a transparent observation board is embedded and installed on one side of the control switch and corresponding to the position of the water circulation filter box. The urban sewage treatment reclaimed water circulating filtration device provided by the invention has the characteristics of scientific and reasonable structure, safe and convenient use, first filtration grids are disposed in a moisture filtration bin for graded filtration of incoming urban sewage, thus avoiding too many impurities in urban sewage, the first filtration grids are blocked by a baffle plate, and standby filtration grids can be replaced for filtration of urban sewage, pull handles set at oneends of sliding buckets can be pulled to draw the sliding buckets out, thus rapidly cleaning the filter residue filtered on the first filtration grids, and not affecting urban sewage filtration treatment during filter residue cleaning.

The invention relates to a soil heavy mental fixing agent and a preparation method therefor and application thereof, particularly a soil heavy mental fixing agent. The soil heavy mental fixing agent is a compound which is compounded by a component A and a component B, wherein the component A is biomass power plant ash particles and the component B is selected from the following substances: alginic acid, alginate or combination thereof. The invention further discloses the preparation method therefor and application thereof. The preparation method therefor has the characteristics of being simple in process, low in cost and convenient to implement and popularize on a large scale. Heavy metals in soil can be efficiently and persistently fixed by using the fixing agent.

The invention relates to the technical field of food processing, and discloses screening-type micro-processing equipment for peeling of highland barley. The screening-type micro-processing equipment comprises a peeling processing device, the two sides located at the top of the peeling processing device are welded to the two ends of the bottom of a feeding supporting device respectively, putting openings are clamped in inner cavities in the two sides of the top of the feeding supporting device, putting pipes are welded to the bottoms of the two putting openings, one ends of the bottoms of the two putting pipes are inserted into the two sides of the top of a feeding hopper respectively, the two sides of the bottom of the feeding hopper are welded to the inner sides of two fixing clamping bases, the two fixing clamping bases are welded to the two sides of the top of the peeling processing device respectively, and the two sides of the top of a discharging hopper are inserted into inner cavities of the bottoms of the two sides of the peeling processing device. According to the screening-type micro-processing equipment for peeling of the highland barley, a user puts highland barley required to be peeled into the feeding hopper, highland barley skins can be subjected to hull breaking through a hull breaking device, peeled skins can be effectively reduced through generated centrifugalforce, and fall down along with the highland barley, and the peeling effect on the highland barley is thus improved.

The invention relates to an agricultural product quality detecting and screening device. The device comprises a screening box, a feeding hopper and a collecting box, a regulating and controlling mechanism and a screening mechanism are arranged on the screening box, the regulating and controlling mechanism comprises a limiting device and a discharging device, and a cleaning device communicating with the discharging device is arranged outside the screening box. The screening mechanism is further composed of a double-selection device and a shaking device in a matched manner, the feeding hopper is arranged at the top of the limiting device, and the collecting box is fixedly installed in the screening box and located below the double-selection device. According to the agricultural product quality detecting and screening device, screening is conducted through a double-layer screening net, impurities of different sizes can be separated conveniently, meanwhile, stacked agricultural products can be pushed and scattered through relative rotation of stirring blades and a screening net, and the situation that the screening efficiency is affected due to stacking is avoided; and meanwhile, a vibration sensing rod in a vibration device regularly pushes the double-layer screening net to shake, the screening efficiency is further improved, and the screening effect of the device is good.

The invention relates to a household garbage pretreatment device and relates to the field of household garbage treatment. The device comprises a rack, a box is arranged on the rack, and the upper portion of the box is open; a baffle for containing household garbage crosses the middle of the box, multiple water leakage holes are formed in the baffle, and a water outlet pipe is arranged at the bottom of the box; an extrusion device for moving towards the baffle is arranged above the box and comprises an extrusion plate arranged above the box, the extrusion plate is parallel to the baffle, and adriving device for driving the extrusion plate to move towards the baffle is arranged above the box; the first driving device is driven so that the first driving device can drive the extrusion plate to move towards the baffle, moisture in the household garbage on the baffle is extruded out by the extrusion plate, the moisture contained the household garbage is reduced, and the effect of treating the household garbage in the later period is improved.

The invention provides a clean combustion heating stove for civil use. The clean combustion heating stove for civil use comprises a hearth, a fire grate, an ash hopper, a primary air inlet and a chimney; the chimney is provided with a waste heat recycling box; and a plane heat exchange water jacket is arranged on the upper portion of the hearth. According to the improvement of the innovative structure, a cylindrical air supply cavity formed by an inner air ring, an outer air ring and a lower end face is arranged at the lower center of the plane heat exchange water jacket; the outer air ring and the inner air ring are tangential and are provided with an outer ventilation hole and an inner ventilation hole in a staggered manner; the lower end face of the air supply cavity is closed or is provided with an end face ventilation hole; and a secondary air inlet pipe is introduced from the exterior of the hearth and is connected to the cylindrical air supply cavity. According to the clean combustion heating stove for civil use, by means of the structural improvement, the hearth is internally divided into three combustion spaces for tertiary air inflow combustion supporting, air is supplied for volatile components which are obtained when fuel is heated and separated out but is not combusted in time for combustion supporting, after combustible substances are sufficiently combusted many times, the heat converting efficiency is substantially improved, and combustible materials and pollutants contained in exhausted smoke are reduced, so that the pollution discharge problem caused when combustion of a civil use fuel coal stove is not complete can be solved.

A combustion device can reduce coal dusts, NOx or nitrous oxide contained in combustion exhaust gas. The combustion device comprises: a vertical double-layer cylindrical furnace body comprising an outer cylinder and a inner cylinder with a specified combustion space; a superior combustor allowing pyrolysis gas to perform hybrid combustion with primary combustion air in the combustion space; a line for supplying the pyrolysis gas to the superior combustor; a line for supplying the primary combustion air to the superior combustor; an inferior combustor which is disposed more lowly than the superior combustor, ejects secondary combustion air, and allows the uncombusted gas in the combustion space to perform hybrid combustion with the secondary combustion air; and a line for supplying the secondary combustion air to the inferior combustor. A lower end opening of the inner cylinder forms a flow path for discharging the combustion exhaust gas from the combustion space. The superior combustor comprises a first combustion port with an opening at the upper inner circumferential wall of the outer cylinder for ejecting the pyrolysis gas and the primary combustion air along the circumferential direction of the upper inner circumferential wall of the outer cylinder and forming a rotating flow in the combustion space.

The invention discloses a boiler waste heat recycling device. The boiler waste heat recycling device comprises a boiler body, wherein a smoke discarding end of the boiler body is fixedly connected toa smoke discharging pipe; a water pipe is arranged at the outer side of the smoke discharging pipe in a sleeving manner; the upper side of the boiler body is fixedly connected to a heat insulating plate; a heat insulating layer is arranged at the inner side of the heat insulating plate; the left side of the water pipe is a water inlet; the right side of the water pipe is a water outlet; the waterinlet and the water outlet penetrate through the heat insulating plate and extend to the exterior of the heat insulating plate; the upper side of the heat insulating plate is fixedly connected to a filter box; the lower side of the filter box communicates with the smoke discharging pipe; two installing holes are formed in the right side of the filter box; and a fixing plate is arranged at the right side of the filter box. The boiler waste heat recycling device has reasonable structure design; the water pipe is of a spiral structure; the effect of pure water heating is improved; the heat contained in exhaust gas is fully utilized; and the exhaust gas can be filtered multiple times so as to ensure the emission of the exhaust gas without affecting the life of surrounding residents.

The invention discloses a rotary centrifugal traditional Chinese medicine solid-liquid separation device, which comprises a main water tank. The top of the main water tank is provided with a water inlet weir trough which penetrates the top of the main water tank and extends into the main water tank, one side of the water inlet weir trough is provided with a water inlet pipe communicated with the weir trough, a side wall of the water inlet weir trough is communicated with one end of a water inlet main pipe, and one end, away from the water inlet weir trough, of the water inlet main pipe penetrates the side wall of the main water tank and extends towards the exterior of the main water tank. One end, away from the water inlet weir trough, of the water inlet pipe is communicated with an inertia separation mechanism. The inertia separation mechanism comprises a plurality of arc flow guide plates in annular array, and a plurality of fixing rings are fixed to outer sides of the arc flow guideplates. The rotary centrifugal traditional Chinese medicine solid-liquid separation device has advantages that solid-liquid separation efficiency is greatly improved, and solid particles in liquid are reduced.

The invention discloses an industrial wastewater treatment device and process. The industrial wastewater treatment device comprises a support, and a filter box and a sterilization box are fixedly connected to the two sides of the interior of the support correspondingly. Through cooperative use of a first filter screen, a second filter screen, activated carbon, an ultraviolet lamp, a cathode plate,an anode plate, a sampling mechanism and an aeration mechanism, large-particle impurities can be adsorbed through the first filter screen, the second filter screen and the activated carbon, wastewater can be sterilized through use of the ultraviolet lamp, through use of the aeration mechanism, bubbles can adsorb impurities in wastewater, and the problems that an existing industrial wastewater treatment device cannot selectively and circularly filter the wastewater in the using process, meanwhile, no specific sampling function exists, a user cannot conveniently sample and detect the wastewaterin real time, the sterilization mode is single, and the wastewater cannot be well sterilized and metal particles cannot be well removed are solved.

The invention discloses an air filter with a dust exhaust hole. The air filter comprises a shell and an upper cover, wherein one end of the shell is provided with an opening used for placing a filter element; the outer wall of the end provided with the opening is provided with two symmetrical air inlets; the other end of the shell is provided with a mounting hole connected with a diesel air inlet pipe, and the dust exhaust hole; a mounting groove used for containing the filter element is arranged in the end provided with the opening; the upper cover covers the end, which is provided with the opening, of the shell, and is locked by a locking mechanism; the inner side of the upper cover is provided with an air guide screen which enables air entering the air filter to form spiral airflow; a space jointly formed by the upper cover and the shell performs a filter element fixing function. Air which enters the air filter of the single cylinder diesel is preliminarily filtered to reduce fine particles contained in air entering an air cylinder and avoid the blockage and the failure of the filter element of the air filter of the diesel as much as possible.

The invention relates to the technical field of hydraulic fluid, in particular to a biodegradable fully mechanized mining support electrohydraulic control concentrated solution. The concentrated solution is prepared from, by weight, 6-12% of vegetable oil, 1-3% of alkali, 3-15% of oleic acid, 2-7% of triethanolamine, 0.5-1% of a hard water resisting agent, 0.05-0.5% of a corrosion inhibitor, 0.01-0.05% of a defoaming agent and the balance of water based on the total mass of all the raw material components of the concentrated solution. The concentrated solution disclosed by the invention has excellent biodegradability. The invention further provides hydraulic fluid containing the concentrated solution, and the hydraulic fluid is lower in cost and environmentally friendly.

The invention belongs to the technical field of food processing equipment, and particularly discloses a cereal peeling device. The device comprises a processing box and a motor, a feeding port, a roller couple, a sleeve and a fan are arranged on the processing box, the roller double comprises a first rotating roller and a second rotating roller, a large gear is meshed with a small gear, a first pressing plate and a second pressing plate are arranged on the position, located between the roller double and the feeding port, of the processing box, a sliding groove is formed in the processing box,a sliding block is arranged in the sliding groove, the second pressing plate is hinged to the sliding block, a connecting rod is arranged between the lower portion of the second pressing plate and a belt wheel, a piston head is arranged in the sleeve, a push rod is arranged between the piston head and the processing box, a collecting hole is formed in the processing box, the air outlet of the fanis right opposite to the position of the collecting hole, and a collecting box used for collecting rice is arranged at the lower portion of the processing box. The device is mainly used for peeling the rice, and solves the problem that in the rice milling process, dust is adhered to the surface of the rice, and then the fineness and eating can be affected.

The present invention relates to a rice hull ash collection method by spraying, and belongs to the technical field of environmental protection. In particular, the method comprises the following processes: roughly burning rice hull hulls and discharging slag ash, removing ash from waste gas by multi-pipea multi-tube ash collector, removing dust ash from the waste gas by spraying, and drying and discharging hull ash by a fan. drying the waste gas, and discharging the dried waste gas by a fan. The beneficial effects of the present invention are that: the rice hull ash is maximatily maximally collected and utilized. At the same time, environment is protected through reducing the rice hull ash in the discharged waste gas. The method in the present invention achieves the effects of comprehensively utilizing resources, saving energy sources, reduce reducing emissions, saving energy and protecting environment.

The invention discloses an efficient plasma cutting machine, and relates to the technical field of plasma cutting. The efficient plasma cutting machine comprises a mounting frame and a cutting gun, a gas intake and exhaust device is mounted on the mounting frame, and the end of the mounted cutting gun sequentially penetrates through the mounting frame and the gas intake and exhaust device; combustion-supporting gas is pumped by the gas intake and exhaust device; and the air outlet end of the gas intake and exhaust device communicates with a deep groove formed in the mounting frame, and a filtering part is mounted in the deep groove. According to the efficient plasma cutting machine, gas suction of a gas suction pipe of the gas intake and exhaust device is achieved through the air inlet of the gas intake and exhaust device in the process of achieving combustion-supporting gas inlet, smoke generated in the cutting process is absorbed, the absorbed smoke passes through the arranged filtering part, and particulate matter contained in the smoke is effectively reduced.

The invention discloses a synthetic technology of omeprazole, and relates to the field of pharmacy. The synthetic technology comprises the following steps that a chloride solution and an alkaline solution of a benzimidazole derivative are mixed to generate a condensation reaction, in the presence of a catalyst and under the alkaline condition, a product of omeprazole sulfur ether obtained after the condensation reaction has an oxidation reaction under the action of an oxidant to generate the omeprazole, and the molar ratio of chloride and the benzimidazole derivative is 1 to (1.4-1.6). According to the synthetic technology of the omeprazole, in the oxidation reaction process, the alkaline condition is kept for a reaction, the conversion of impurities is effectively controlled, and the impurities contained by the meoprazole are reduced, meanwhile, the proportion of main raw materials is reasonably adjusted, reaction by-products are reduced, the residue of materials which are not reactedcompletely in products is lowered, and the impurities and the cost are lowered.

The invention belongs to the field of environmental geotechnical and environmental engineering, and in particular relates to a leaching test device and method for heavy metal pollutants. The invention provides a leaching test device for testing the release and migration of heavy metal elements. The experimental device can monitor the physical condition of each layered rock-soil body and the release and migration of heavy metals to groundwater, and can monitor each layered rock-soil body and leachate. By performing real-time sampling and detection, the test device can simulate the leaching, migration and transformation process of heavy metal elements in various layers of rock and soil. The present invention also provides a method for carrying out a leaching test for testing the release and migration of heavy metal elements, including: filling a leaching column, and testing the obtained time intervals, different time intervals, The concentration of heavy metal elements in layers, solid samples of different flow rates and leached liquid samples. This method can effectively simulate the concentration parameters of heavy metal elements in different leaching column layers under leaching action.

The invention discloses an aldehyde removal device for producing an aldehyde-free adhesive for automotive trims. The aldehyde removal device comprises a main shell, an air inlet, an air outlet, an exhaust device, a control valve, a discharge hole and a tank cover, wherein a raw material pipeline and an activated carbon pipeline are arranged on the main shell; a first electromotor is fixed above the main shell; the first electromotor is connected with a first rotating shaft; stirring blades are arranged on the first rotating shaft; the air inlet and the air outlet are positioned in the top surface of the main shell; a first filtering net is arranged on the air inlet and the air outlet; the control valve is positioned between the main shell and a filtering shell; a second filtering net is arranged inside the filtering shell; the exhaust device comprises fan blades, a second rotating shaft and a second electromotor; the fan blades are connected with the second electromotor through the second rotating shaft. Due to adoption of the raw material pipeline and the activated carbon pipeline, raw materials and activated carbon can be uniformly mixed inside the main shell of the aldehyde removal device for producing the aldehyde-free adhesive for automotive trims.

The invention relates to the technical field of semiconductor packaging equipment, and provides a plastic packaging press. The press aims to solve the problem that a large number of bubbles exist in a liquid plastic packaging material after the plastic packaging material is molten due to the fact that a solid plastic packaging material cannot fill a mold hole and a large amount of air exists in a mold in an existing plastic packaging press, and comprises a supporting lower mold, an upper mold and an injection head. The upper mold can be pressed on the supporting lower mold, the upper surface of the supporting lower mold is provided with a first containing hole and a first runner communicated with the first containing hole, the lower surface of the upper mold is correspondingly provided with a second containing hole and a second runner communicated with the second containing hole, the upper mold is further provided with a feeding channel communicated with the second runner, and the injection head is connected with a driving rod. The injection head is matched with the feeding channel and slides along the feeding channel; and the injection head comprises a shell, a sliding way is formed in the shell, an injection rod with a T-shaped longitudinal section is slidably connected into the sliding way, a first through hole communicated with the sliding way is formed at the upper end of the shell, and a second through hole communicated with the sliding way is formed in the bottom face of the shell.

The invention discloses a substation insulator cleaning system comprising a high-pressure water gun, a travelling device and a pure water preparation device. According to the substation insulator cleaning system, through the pure water preparation device, mechanical impurities, suspended matter, organic pollutants, organic matter, bacteria, virus and irons in a water purifying system are effectively removed, the conductivity of water is effectively decreased, the electrical resistivity is increased, ultrapure water is prepared, and the prepared ultrapure water is delivered to the high-pressurewater gun through a booster pump and a hose. In the scheme, the water for cleaning a substation insulator is the ultrapure water, the charged ions contained in the water are effectively removed, theconductivity of the water is decreased, the electrical resistivity of the water is increased, and the safety of substation insulator on-line cleaning is improved.

The invention provides a mechanical shifting hand and a robot, and relates to the technical field of coal production equipment. The mechanical shifting hand comprises an installation assembly, a guidehead and a shifting rod device, wherein the installation assembly is used for being connected with a driving device, and under the action of the driving device, the installation assembly can do reciprocating motion in a first direction and a second direction. The mechanical shifting hand can be connected with the driving device, under the drive of the driving device, the mechanical shifting handcan move in the first direction and the second direction, the guide head on the mechanical shifting hand faces the direction opposite to the conveying direction of a conveying belt for conveying coal,the shifting rod device of the mechanical shifting hand can shift gangue located at the edge of the conveying belt away from the conveying belt, and then the separation between the gangue and the coal is achieved.

The invention discloses a flame-retardant antibacterial coating for an elevator and a preparation method of the coating. According to the invention, the coating is prepared from sodium diacetate, triphenyl phosphate, aluminum phosphide, nano modified bamboo charcoal, nano zinc oxide, potassium sorbate, graphite fiber, PVC resin, aluminum hydroxide powder, magnesium hydroxide powder, aluminum oxidepowder, quicklime powder, paraffin, sodium tetraborate, pine-soot ink, carbon tetrachloride, terpilenol, dodecyl glucoside, ethoxyquinoline and polyhexamethylene biguanidine hydrochloride through thesteps of mixing, calcining, ultrasonic dispersion and curing. Tests show that the coating prepared by the invention has excellent flame-retardant and antibacterial effects.

The invention provides medicinal material washing equipment capable of collecting impurities obtained after washing. The medicinal material washing equipment comprises a top cover, an electric motor,a power plug, a power socket, an N-shaped rotating shaft, a medicine clamp, a threaded column, a rubber blanket, a main body, a washing trough, a device cavity, a sliding bin, a water pump control switch, a water draining pipe, a drawer, a nanometer filter net, a drainage pipe, a water purifier, a water storage tank, a water pump, a water inlet pipe, a spray head, supply hubs and a protection cover plate. The left end of the top cover is provided with the power plug, and the power plug is electrically connected with the power socket. The power socket is arranged on the top of the left side ofthe main body, and the power socket is electrically connected with the supply hubs. The end face of the top of the main body is provided with the washing trough, the N-shaped rotating shaft is locatedinside the washing trough, the relatively large impurities in water flow are filtered through a nanometer filter net inside the drawer, the impurities are reserved in the nanometer filter net, and workers can conveniently remove the residues.

The invention discloses a preparation method of a bio-based chinlon 5X fiber material. The preparation method comprises the following steps that 1), 1,5-pentanediamine mixed fermentation liquor and binary acid are mixed and subjected to polymerization reaction to obtain polyamide salt mixed liquor, and the polyamide salt mixed liquor is treated to obtain polyamide salt, wherein the 1,5-pentanediamine mixed fermentation liquor is mixed fermentation liquor obtained by preparing 1,5-pentanediamine through a biological method; 2), polymerization reaction is carried out on the aqueous solution of the polyamide salt and a molecular weight regulator to obtain a polyamide 5X polymer; and 3), the melt of the chinlon 5X polymer is sprayed through a spinneret plate to obtain a melt trickle, the melttrickle is cooled and solidified to form filaments, and fiber post-processing is carried out on the solidified filaments to obtain the bio-based chinlon 5X fiber material. According to the preparationmethod, dibasic acid is added into the 1,5-pentanediamine mixed fermentation liquid for reaction, polyamide salt can be directly obtained, the conversion rate can be increased, energy consumption canbe reduced, and the problem of environmental pollution can be avoided; and the polyamide salt mixed solution is purified to obtain polyamide salt crystals for subsequent reaction, so that side reaction is avoided.