93 results about "Acid concentration" patented technology

The utility model belongs to the technical field of heat exchanger cleaning, and discloses a heat exchanger cleaning device which comprises a box body, a circulating system and an acidity meter, acid liquid is contained in the box body, the circulating system is connected with the box body and a heat exchanger and can enable the acid liquid in the box body to enter the heat exchanger in a circulating mode, and the acidity meter comprises a probe and a display screen. The probe is arranged in the box body and used for detecting the concentration of the acid liquid in the box body, and the display screen is used for displaying the real-time acid concentration of the acid liquid. According to the heat exchanger cleaning device provided by the utility model, the acid liquid is used for circularly cleaning the heat exchanger, so that the heat exchanger is prevented from being disassembled and assembled, and the working difficulty of workers is reduced; it is ensured that the acid liquid can chemically react with scale every time the acid liquid enters and exits the heat exchanger, effective cleaning is achieved every time the acid liquid enters and exits the heat exchanger, and the cleaning efficiency of the heat exchanger is effectively improved.

The invention discloses a resourceful treatment method for stainless steel pickling waste liquid and waste water. The waste liquid is divided into high-concentration waste liquid and low-concentration waste liquid according to the acid concentration and the salt concentration to be treated respectively. Sequentially recovering gypsum, chromic hydroxide, nickel sulfide, ferrous hydroxide and manganese-rich slag from the low-concentration waste liquid through gradient precipitation; and neutralizing free acid from the high-concentration waste liquid by using ferrous hydroxide generated in a low-concentration section, cooling and crystallizing to recover ferrous sulfate, deeply removing nickel by using nickel sulfide generated in the low-concentration section, and precipitating to recover chromium hydroxide. In the whole process, generation of ferric iron is strictly controlled, and high-value productization recovery of free acid and all metals is achieved. The method has the advantages of low medicament consumption, high metal recovery rate, high product value, no secondary pollution and the like.

Proposed is a method for producing a grain-oriented electromagnetic steel sheet, with which it is possible to further improve magnetic properties and suppress fluctuations in magnetic properties and film properties in a coil without using an inhibitor. This method for producing a grain-oriented electromagnetic steel sheet includes: a hot rolling step for hot rolling a steel roll material having a constituent composition which contains C, Si, Mn, acid-soluble Al, N and Sb and in which S and Se are contained so as to satisfy a prescribed relational expression; an optional hot-rolled sheet annealing step; a cold rolling step; an acid washing step; a primary recrystallization annealing step; and a finish annealing step. In intermediate annealing in the hot-rolled sheet annealing step or cold rolling step before a final cold rolled steel sheet is obtained, the γ-phase fraction in the steel structure at the annealing temperature is 1.0-25.0 vol%, the average cooling speed after annealing is 20-50ºC / s, acid washing is carried out using a solution which contains 2-15 mass% of Fe ions and has an acid concentration of 1-20 mass% in the acid washing step, and an annealing separating agent contains a Ti compound at a quantity of 0.3-8 parts by mass in terms of Ti relative to 100 parts by mass of magnesia in the finish annealing step.

This invention relates to the field of scheelite processing technology, and particularly to a method for processing scheelite ore, comprising the following steps: first, slurry conditioning; pH adjustment, the method for controlling the pH value of the reaction solution includes: after controlling the reaction solution to a first pH value, lowering the pH value to a second pH value every first time period, and finally controlling the residual acid concentration of the reaction solution to be controlled at 8-11 g / L and maintained for a second time period; first filtration; second slurry conditioning; leaching; second filtration. Using the scheelite ore processing method provided by this invention, after treating the scheelite ore with a first reagent under certain conditions, followed by leaching treatment, effectively reduces the tungsten content in the slag and reduces tungsten loss. This method has the advantages of a short process, less reagent addition, less slag and solution formation, and significantly reduced tungsten loss.

The invention relates to a weighted authigenic acid as well as a preparation method and application thereof. The weighted authigenic acid comprises an acid generating component and a weighting component, the acid generating component comprises an acid generating agent, a product solubilizer, a catalyst and a corrosion inhibitor; the acid generator comprises organic weak acid and a chlorine-containing acid generator; the weighting component comprises weighting salt, a resistance reducing agent and water; the aggravated authigenic acid is high in acid generation efficiency and controllable in acid generation concentration, the concentration of generated H < + > can reach up to 4.95 mol / L, the aggravated authigenic acid has high corrosion inhibition capacity, the corrosion rate is as low as 30 g / (m < 2 >. H) or below, the preparation method is simple, raw materials are easy to obtain, and the aggravated authigenic acid can be used for efficient transformation of ultra-deep high-temperature carbonate reservoirs with the temperature reaching up to 120-200 DEG C.

The invention provides a pickling line monitoring system, which comprises a sensor, a control module and an actuator, the sensor monitors the acid concentration, temperature, liquid level and pickling line transmission speed of a pickling tank, and the actuator is used for controlling the technological actions of acid supplement, acid dilution, acid discharge, heating and circulation of the pickling tank. The control module controls the actuator in real time according to data of the sensor so as to maintain the concentration of acid liquor in the pickling tank to be close to the optimal value of the pickling process; the real-time control strategy of the control module comprises the steps that output parameters of an actuator are adjusted in real time through a feed-forward control and PID feedback control integrated composite control strategy, feed-forward compensation is improved for the change of the transmission speed of the pickling line through feed-forward control, and disturbance of acid concentration, temperature and liquid level data to output is reduced through PID feedback control setting dead zones. According to the invention, the acid concentration adjusting precision and the automation degree of the pickling line are improved.

The invention discloses a titanium dioxide waste acid concentration system and method, and belongs to the technical field of sulfuric acid process titanium dioxide production or similar waste acid concentration. The system comprises a primary concentration and ferrous separation module and a secondary concentration and ferrous separation module. The primary concentration and ferrous separation module realizes primary concentration and solid-liquid separation of waste acid through an evaporation concentration kettle, a flash tank and a primary diaphragm filter press; and the secondary concentration and ferrous separation module is used for carrying out deep concentration and secondary separation on the waste acid through a scraper evaporator and a secondary diaphragm filter press. The system adopts the technologies of ultrasonic descaling, stepped concentration and solid removal, partition temperature control film evaporation and the like, and is matched with a mirror surface level inner wall scraper evaporator and an adjustable rapping device, so that the problem of scaling blockage in the waste acid concentration process is effectively solved. The method can increase the concentration of waste acid to 60% or above, realizes continuous automatic operation, and has the advantages of low equipment investment, low operation cost, environmental friendliness, high resource recovery rate and the like.

The present application relates to the technical field of rhombohedral manganese ore leaching, and particularly discloses a rhombohedral manganese ore dressing and smelting combined efficient leaching process, which comprises the following steps: 1. low-acid leaching: rhombohedral manganese ore powder is added into low-acid anolyte for stirring leaching, the acid concentration of the anolyte is 42-46 g / L, 8-10 cubic meters of low-acid anolyte is used for each ton of rhombohedral manganese ore powder, after the leaching is completed, the end point pH value is controlled to be 6.0-6.5 by adding a neutralizing agent, and the leaching slurry is concentrated by a thickener to separate supernatant and concentrated ore slurry. The present application can efficiently realize rhombohedral manganese ore leaching and is suitable for promotion.

The invention relates to the field of chemical analysis and detection, in particular to a method for rapidly detecting the concentration of industrial concentrated acid based on neutralization reaction, which comprises the following steps: 1, theoretical calculation; converting molar concentration according to acid density and mass fraction; 2, accurately measuring the volume of target acid by using a pipette; 2, injecting 100-150ml of pure water into the triangular flask, and adding 3-5 drops of phenolphthalein; 3, slowly injecting an acid sample into the triangular flask, and slightly shaking and uniformly mixing; 4, adding 10.00 ml of NaOH solution by using the pipette, and oscillating for 10-20 seconds; 3, result interpretation: transparency and colorless: acid is excessive when the acid concentration reaches the standard, pH is less than or equal to 8.2 after neutralization, pink lasts for 20-30 seconds, and reinspection is needed when the acid concentration is insufficient and the pH is greater than or equal to 8.3. The method has the beneficial effects that 1, a reverse judgment method is adopted, namely the conventional end-point titration is replaced by fixed alkali amount, so that the detection time is shortened to 2 minutes; 2, safety design: pre-dilution reduces the risk of acid mist, and only a trace amount of raw acid is needed to avoid acid corrosion; 3, multi-acid adaptation: compatibility with detection of different types of concentrated acids is realized through pipetting volume adjustment;

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.

This invention belongs to the field of fly ash treatment technology, specifically disclosing a method for separating potassium and sodium from fly ash, including the following steps: adjusting the acid concentration in the fly ash washing solution to 40-65% and the temperature to 40-65℃, adding a sodium precipitating agent and maintaining the reaction temperature, and filtering to obtain sodium salt and potassium-containing waste liquid. This invention utilizes precipitation to recover sodium ions from fly ash washing solution. After filtration, sodium salt precipitate and potassium-containing waste liquid are obtained. During this process, the reaction is controlled under acidic conditions to prevent potassium ion precipitation. At 40-60℃, the sodium precipitating agent reacts with sodium ions to obtain sodium salt precipitate with large crystals, which allows for more convenient and thorough filtration, resulting in better separation of potassium and sodium ions in the fly ash washing solution. The sodium salt precipitate is further washed with a displacement agent to replace the potassium ions attached to the surface of the sodium salt precipitate with sodium, improving the purity of the sodium salt product. Finally, multiple water washings are performed to reduce the acidity of the sodium salt precipitate, resulting in a sodium salt product with stable quality.

Embodiments of the present technology include electroplating methods that include providing a first portion of an electrolyte feedstock to a first compartment of an electrochemical cell. The first portion of an electrolyte feedstock may be characterized by an initial metal ion concentration and an initial acid concentration. The methods may include providing a second portion of an electrolyte feedstock to a second compartment of the electrochemical cell. The second compartment and first compartment may be separated by a first membrane. The methods may include providing an acidic solution to a third compartment of the electrochemical cell. The third compartment and second compartment may be separated by a second membrane. The acidic solution may be characterized by an initial acid concentration. The methods may include applying a current to an anode of the electrochemical cell. The anode of the electrochemical cell may be disposed proximate the first compartment and across from the first membrane.

An electroplating system including a Cu bath disposed within a vessel, the Cu bath characterized by a predetermined threshold of Cu concentration, and a predetermined threshold of acid concentration, and where a substrate is submerged in the Cu bath; and a jet array configured to spray a fluid onto the substrate, where the fluid has a same composition as the Cu bath. Further, a method including spraying a fluid onto a substrate with the jet array, wherein the fluid has a same composition as the Cu bath and where spraying the substrate increases a deposition rate of a deposited Cu onto the substrate, where the predetermined threshold of acid concentration increases a bath conductivity of the Cu bath, and where the increased bath conductivity improves a coplanarity of deposited copper structure.

This invention proposes an indirect steam heating device resistant to strong acid corrosion, belonging to the field of steam heating technology for strong acid corrosion resistance. Addressing the technical problems of existing strong acid environment heating technologies, such as acid concentration dilution, poor corrosion resistance of ordinary materials, low heating efficiency of plastic materials, and small heat exchange area, this invention provides an indirect steam heating device resistant to strong acid corrosion in strong acid environments. It achieves the technical goals of not diluting the acid concentration, long-term resistance to strong acid corrosion, and efficient increase in the temperature of strong acid solutions. Furthermore, by optimizing the pipeline layout to increase the heat exchange area, it further improves heating efficiency, meeting the requirements for efficient oxide layer removal in beryllium copper strip production.

The invention discloses a method for inhibiting reduction of the acid concentration of a steam stripping defluorination tower in a wet-process phosphoric acid purification process, which comprises the following steps: 1) after heavy removal and coarse decoloration of phosphoric acid with the concentration of 79% obtained by concentration of concentration equipment, introducing the phosphoric acid into a membrane filter for filtration, and caching the phosphoric acid in a clear liquid aeration tank; 2) monitoring whether the temperature of the phosphoric acid flowing out of the heat exchanger reaches 100-120 DEG C in real time, and if the temperature of the phosphoric acid is lower than 100 DEG C, increasing the flow rate of steam entering the heat exchanger to 1.5-2.2 m < 3 > / h; and 3) defluorinating phosphoric acid in the steam stripping defluorination tower, feeding the defluorinated phosphoric acid into a premixer through a pipeline, mixing the defluorinated phosphoric acid with hydrogen peroxide, and sequentially feeding the mixture into a first decolorizing tower and a second decolorizing tower which are connected in series through a pipeline. After the method is used, phosphoric acid with the mass concentration of 75-77% and the chromaticity of 10-20 black units can be directly obtained without increasing the concentration of phosphoric acid in concentration equipment.

Peroxycarboxylic acid compositions comprising compatible ionic compounds to deliver conductivity signals to enable monitoring of the peroxycarboxylic acid concentration by conductivity when diluted for use are disclosed. Methods of measuring peroxycarboxylic acid concentration by conductivity are also disclosed. Beneficially, conductivity measurement allows a user to determine concentration of the peroxycarboxylic acid at a point of use without cumbersome titration steps to determine the concentration providing various benefits at an application of use.

The present application relates to a kind of acid tank dismantling construction methods in confined space, neutralize acid concentration in acid tank, use purified water to carry out cycle flushing;According to the size of structure platform column spacing, cut several sections segmentedly;Use air pick to remove acid-resistant brick width 300mm in cutting seam, expose tank body rubber lining;Use flat shovel to remove lining in cutting seam;Use oxyacetylene along cutting seam to disintegrate tank body;Remove the pattern plate of structure platform above acid tank, hoist tank body by crane through below platform, rotate 90 degrees, and hoist tank body away from platform edge;Lay down roller steel pipe below, hoist tank body out and place in specified location area and stack.The present application can realize the quick dismantling of acid tank, solve the problem that acid tank is not easy to remove in confined space.The present application can shorten the acid tank dismantling time, and the construction method is reliable in connection;Use crane to disintegrate and hoist to remove, reduce heavy physical labor, improve work efficiency.

The invention discloses an MTW molecular sieve as well as a preparation method and application thereof. The acid concentration in pores of the MTW molecular sieve accounts for 20-90% of the total acid concentration. According to the invention, the regulation and control of the acid distribution inside and outside the MTW molecular sieve pore can be realized only by regulating and changing the types and the addition amount of the template agent and the alkali metal ions in the raw materials. The molecular sieve with the adjustable number of acid sites in the pore channel shows high activity and adjustable para-position / meta-position product selectivity in an alkylation reaction of olefin / aromatic hydrocarbon.

Stimulation treatments are designed and performed in a manner that takes into account radial acid flow into the formation. A reservoir core plug is selected and a linear core flow test is performed. The core flow test comprises measuring a flowing fraction, injecting into the core plug a treatment volume of at least one candidate stimulation fluid at an injection rate at reservoir conditions, and measuring an effective reaction rate constant. The linear flow data are then scaled to radial flow. A skin, an acid concentration at a wormhole tip and a fluid velocity at a wormhole tip are calculated. A stimulation treatment is then performed. The method can also be performed on analog cores. The stimulation treatment may be matrix acidizing, fracture acidizing or acidizing natural fractures.

This invention provides a method, apparatus, and medium for optimizing uniform acid distribution in long horizontal wells, belonging to the field of oil and gas. The method includes: determining a temperature expression for acid viscosity based on an initial acid formulation; determining the wellbore temperature field based on horizontal well parameters and construction parameters; calculating the wellbore acid concentration distribution, wellbore wall acid concentration distribution, and wellbore pressure distribution based on construction parameters, the temperature expression, reservoir parameters, and the wellbore temperature field; determining whether the uniform acid distribution conditions are met based on the wellbore acid concentration distribution, wellbore wall acid concentration distribution, and wellbore pressure distribution; if met, determining the current initial acid formulation and construction parameters as the corresponding horizontal well acid distribution scheme; otherwise, adjusting the acid formulation and / or construction parameters, recalculating, and reassessing. This allows for determining the feasibility of the acid distribution scheme before actual construction, shortening the design time, achieving a uniform acid concentration distribution on the wellbore wall, and realizing uniform acid distribution in long open-hole horizontal sections.

The invention provides an organic diverting acid blocking removal liquid system and a preparation method, aiming at solving the problem that the existing diverting acid only depends on a diverting agent to delay the reaction speed of acid rocks and cannot meet the requirement of blocking removal of a deep part of a reservoir, and the organic diverting acid blocking removal liquid system and the preparation method thereof are designed aiming at a specific diverting agent to design a solid organic acid with a specific molecular structure. The solid organic acid has good compatibility with the diverting agent, not only can greatly delay the acid rock reaction speed, but also can greatly increase the viscosity of the unblocking liquid system when the acid rock reaction is about to be finished, so that the purpose of diverting the acid liquid is achieved. When the concentration of the solid organic acid is 30%, the acid rock reaction time of the system can reach 280 min, the steering time occurs after the acid rock reaction lasts for 250 min, the system has deep plug removal steering capacity, the purpose of deep uniform plug removal of an oil and gas reservoir is achieved, the corrosion rate of marble can reach 88% through final conversion according to a corrosion rate measuring method, and the system can be applied to deep plug removal of the oil and gas reservoir. The requirement on the corrosion capability of the unblocking liquid is met.

The invention discloses a method for eliminating stamping galling of pickled automobile structural steel, which is characterized in that a uniform honeycomb shape is formed on the surface of a steel plate through optimization of a pickling process, and the specific operation is as follows: the automobile structural steel sequentially passes through five continuous pickling tanks for pickling in the pickling process, the pickling speed is controlled to be 50-90m / min, and the temperature of the pickling tanks is 65-85 DEG C; and the free acid liquor concentration, the total acid concentration and the iron ion concentration of each pickling tank are controlled. According to the method, the uniform honeycomb shape is formed on the surface of the steel plate, friction between the strip steel surface and a grinding tool is reduced during stamping, and therefore the stamping galling problem of the pickling plate is solved.

The application provides a heterogeneous reservoir acid fracturing parameter design method and system, the method constructs an acidification reconstruction geometric model for a reservoir to be reconstructed, introduces required acidification section length and section thickness data to calculate acid liquid flow rates in fractures under different construction discharge capacities in combination with fracture attribute data, further considers acid etching reaction rates and mass transfer coefficients to calculate acid concentrations on inner walls of fractures reacted with a reservoir matrix, determines etching widths of natural fracture walls according to attribute parameters of the reservoir matrix, further calculates reservoir etching volumes corresponding to different construction acid amounts and acid etching fracture widths and lengths, finally decides corresponding acid etching fracture conductivity capacities according to a correction principle of an N-K model, and selects optimal acid injection parameters according to preset optimization conditions. By using the scheme, the problems of small calculation scales and complicated operations in the prior art are effectively overcome, analytical solutions are flexibly used in the calculation process, and an acid injection scheme with optimal acid etching effects and conductivity capacities is accurately and efficiently selected.

The application belongs to the technical field of water treatment, and particularly discloses an acid recovery device. The acid recovery device comprises an acid separator and acid concentration electrodialysis. The acid separator is sequentially arranged and placed by a positive charge microporous semi-permeable membrane, a negative charge fibrous filler, a positive charge microporous semi-permeable membrane, a raw material chamber separation net and a positive charge microporous semi-permeable membrane. The components arranged in this way can be arranged in multiple ways to realize more efficient treatment. Dilute acid from the acid separator enters the acid concentration electrodialysis component for treatment. The acid recovery device has the advantages of fast diffusion speed, high salt concentration of waste acid, the ability to treat waste acid with high salt concentration, high recovery rate and the like.

The invention provides a cyclohexanone-oxime transposition process flow and a cyclohexanone-oxime transposition device for partitioned sulfuric acid concentration supply, which are used for partitioned supply and accurate control of sulfuric acid concentration in different stages of transposition reaction, in the transposition process flow, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel and a low-concentration acid channel through an intelligent metering and acid adding module, and the high-concentration acid channel and the low-concentration acid channel are communicated with the high-concentration acid channel and the low-concentration acid channel; the high-concentration acid channel is used for a one-step transposition reactor of a one-step reaction zone of the two-step transposition process, the low-concentration acid channel is used for a two-step transposition reactor of a two-step reaction zone of the two-step transposition process, and in the transposition process flow, a multi-mode fuzzy self-adaptive prediction PID control algorithm is adopted, control modes are switched according to reaction stages, and the multi-mode fuzzy self-adaptive prediction PID control algorithm is adopted. The first-step reaction zone adopts high-precision temperature-acid concentration cascade control, and the second-step reaction zone adopts by-product prediction feedforward control; according to the invention, partitioned supply and accurate control of sulfuric acid concentration in the first-step reaction zone and the second-step reaction zone can be realized, the reaction efficiency and selectivity are improved, and acid consumption and by-product generation are reduced.

The application discloses an acid-resistant anion exchange membrane, a preparation method and application thereof, and relates to the technical field of ion exchange membranes. The acid-resistant anion exchange membrane is prepared by the following steps: taking N-allyl benzylamine as a monomer, copolymerizing the monomer with a crosslinking agent in a solvent, coating the copolymer on a base film, and further crosslinking the copolymer in a hot press through a Friedel-Crafts reaction. The anion exchange membrane prepared through the above technical means is suitable for use in nitric acid (salt) system electrodialysis for acid concentration or acid production, and has the advantages of good acid resistance, low surface resistance, stable long-term performance and long service life.

The invention discloses a polybasic mixed acid concentration detection method. The method comprises the following steps: S1) weighing a sample and diluting; the method comprises the following steps: S1) water bath digestion, S3) total H < + > determination, S4) hydrofluoric acid concentration determination, S5) sulfuric acid and phosphoric acid concentration determination, and S6) nitric acid concentration determination.According to the method, only an acid-base titration electrode and a fluorine ion meter are needed, more titration electrodes and titration reagents are not needed, the operation is simple, and the accuracy is high.

Peroxycarboxylic acid compositions comprising compatible ionic compounds to deliver conductivity signals to enable monitoring of the peroxycarboxylic acid concentration by conductivity when diluted for use are disclosed. Methods of measuring peroxycarboxylic acid concentration by conductivity are also disclosed. Beneficially, conductivity measurement allows a user to determine concentration of the peroxycarboxylic acid at a point of use without cumbersome titration steps to determine the concentration providing various benefits at an application of use.

The present invention relates to the technical field of iron oxide red preparation. Disclosed is a method for preparing high-purity iron oxide red by microwave roasting and ultrasonic-enhanced acid leaching of coal gangue. By controlling the microwave roasting temperature of the coal gangue to be 500°C and the time to be 30 min, the iron dissolution rate reaches 93.6% under the conditions of an optimal ultrasonic power of 300 W, an acid concentration of 20%, an acid leaching temperature of 80°C, an acid leaching time of 30 min, and a liquid-solid ratio of 4 mL / g. A leaching solution is extracted by using a solvent extraction method (TBP-SK-hydrochloric acid system). After extraction, the content of iron ions in the solution is as high as 99.78%; and the optimal pH for hydrothermal treatment is controlled to 11, the temperature is controlled to 170°C and the time is controlled to 3 h, so as to prepare a high-purity iron oxide red product. The iron oxide red has a purity of 99.89%, which meets the requirement (98.5%) of "YHT4 Iron Oxide Standard for Ferrite" (GB / T 24244-2009), and can be used as a raw material for producing high-performance soft-magnetic ferrite.

Disclosed methods employ acid generator components in an underlayer. Acid generated by the acid generator components diffuses into an overlying layer, e.g., a photoresist layer, and provides acid which chemically alters the photoresist, e.g., alters the solubility of the photoresist in a developer solution. The acid that diffuses into the overlying photoresist layer increases the concentration and the uniformity of concentration of the acid in lower portions of the photoresist. The regions of increased acid concentration within the photoresist can increase the photoresists solubility in developer solutions, thereby reducing inadequate development of the photoresist. Reducing inadequate development of the photoresist can reduce the amount of photoresist residue or scum that remains after development is complete.