362results about "Carbonate preparation" patented technology

The invention provides a method for preparing sodium carbonate and co-producing ammonium sulfate from sodium sulfate waste salt, and relates to the technical field of chemical engineering. The method comprises the following steps: mixing sodium sulfate waste salt with water for dissolution, mixing the obtained sodium sulfate waste salt solution with an impurity removal agent for impurity removal, and mixing the obtained impurity removal solution with ammonium bicarbonate for double decomposition reaction to obtain a reaction feed liquid; carrying out primary cold separation on the reaction feed liquid to obtain first filtrate and primary sodium bicarbonate; sequentially washing, drying and roasting the primary sodium bicarbonate to obtain a sodium carbonate product; carrying out secondary cold separation on the first filtrate, carrying out solid-liquid separation to obtain a second filtrate and mixed salt, and reusing the mixed salt in the metathesis reaction; and mixing the second filtrate with an acid adjusting agent to adjust the acid, and carrying out evaporative crystallization on the obtained solution to obtain an ammonium sulfate product and an evaporation mother solution. Industrial-grade sodium carbonate and ammonium sulfate are co-produced by using sodium sulfate waste salt, sodium carbonate and ammonium sulfate meet national standard requirements, and the recovery rate of sodium sulfate is greater than or equal to 90%.

The utility model discloses an atomization rotational flow crystallization device for CO2 resource recovery, which relates to the technical field of recovery of CO2 in combustion flue gas and comprises a spray gas inlet device, a spherical cyclone and a condensation crystallization device. According to the utility model, the atomization rotational flow crystallization device is adopted to realize CO2 resource recovery of flue gas, the flue gas is firstly in full contact with atomization absorption liquid sprayed by the multi-point spraying array assembly to form a flue gas absorption liquid mixture, the flue gas absorption liquid mixture is in a rotational flow state after entering the spherical hydrocyclone, and gas-liquid phase separation is carried out, so that the CO2 resource recovery is realized. The liquid phase is condensed under the condensation action of the condensation crystallization device to obtain a solid-phase product sodium bicarbonate and a liquid-phase absorption liquid, and the liquid-phase absorption liquid is subjected to temperature control adjustment and atomization again to provide an absorption liquid for the multi-point spray array assembly; and the method can also be used for large-scale CO2 resource recovery scenes such as thermal power plants and the like, the process and equipment are stable and reliable, the operation is flexible, and the CO2 absorption conversion rate is high.

Methods of capturing carbon in biochar are provided. The method includes mixing the biochar with an alkaline solution to form an intermediate mixture, and exposing the intermediate mixture to a CO2 source to precipitate calcium carbonate over and in the biochar to form a CO2 weathered biochar. In some cases, the method further includes injecting CO2 into the alkaline wastewater to sequestration / store CO2, which may then be used as mixed water for the production of cementitious composites. The method can be used for upgrading three waste streams, and the treated CO2 weathered biochar maintains the compressive strength of the obtained concrete when replacing part of the pre-cured cement and aggregate components. In addition, the treated CO2-weathered recycled aggregate maintains the mechanical strength of the obtained concrete when replacing part of the aggregate.

The invention belongs to the technical field of chemical engineering and secondary resource utilization, and particularly discloses a collaborative utilization process of sodium sulfate and ammonium-containing waste salt. The high-value utilization method of sodium sulfate provided by the invention comprises the following steps: mixing sodium sulfate, organic ammonium salt and sulfuric acid, and adding water to prepare a mixed solution; extracting the mixed solution by using an extracting agent, and separating a water phase from an organic phase; adding a pH regulator into the water phase to regulate the pH to alkalescence, introducing carbon dioxide gas to fully react, cooling, crystallizing, and filtering to obtain filtrate and sodium bicarbonate precipitate; heating the filtrate for evaporative crystallization to obtain ammonium sulfate; and recovering the organic acid in the organic phase. The invention provides a subversive solution for sodium sulfate by-product accumulation and ammonium-containing wastewater treatment, has double values of resource circulation and carbon emission reduction, and has the advantages of full-flow closed-loop design, wide applicability, high product purity and high economical efficiency in process.

The present invention relates to systems and processes for utilizing produced water and captured carbon dioxide to produce high-value products. The system includes a produced water processing system, a carbon capture system, an electrolyzer, and a conversion chamber. The electrolyzer includes a first chamber, a second chamber, and a semi-permeable membrane and first electrode in the first chamber and a second electrode in the second chamber. The first chamber receives treated saturated produced water. The second chamber is operated at a second operating pressure that is less than the first operating pressure and facilitates the passage of sodium ions across the membrane. A current is applied to the electrodes such that the first electrode functions as an anode and the second electrode functions as a cathode, producing hydrogen gas and sodium hydroxide in the second chamber and chlorine gas in the first chamber. The polarity of the electrodes and the flow of reagents into the first and second chambers and the flow of products out of the first and second chambers may be reversed.

The subject process relates generally to producing an aqueous solution through a simple but highly effective chemical reaction. The aqueous solution is composed of a blended solution with water and an added solubilizer for the chemical reaction. The results produce an ionic solid and an alkaline liquid solution which are useful commercial products, and various applications including but not limited to use as a CO2 capture solvent.

The invention provides a membrane-method carbon capture and solidification method. The membrane-method carbon capture and solidification method comprises a multivalent separation electrodialysis system, a cationic resin column, a bipolar membrane electrodialysis system, a carbon dioxide membrane enrichment device, an absorption tower, a pregnant solution pump, a desorption tower and four-compartment replacement electrodialysis. Alkali produced by bipolar membrane electrodialysis is used as absorption liquid, and acid produced by bipolar membrane electrodialysis is used as desorption liquid. According to the invention, the use cost of the adsorbent and the desorption agent is reduced, the internal balance of the agent system is realized, and meanwhile, the preparation of high-purity potassium bicarbonate can be realized by combining with four-compartment replacement electrodialysis. The system can be used for capturing and purifying carbon dioxide in atmosphere or industrial production and refining a potassium bicarbonate product, and compared with traditional carbon capture, absorption liquid and desorption liquid in the system can achieve circulation in the system, and zero emission is achieved.

The invention belongs to the technical field of sodium bicarbonate preparation, and particularly relates to a method for preparing sodium bicarbonate through sodium waste salt resource conversion. In order to solve the problems of low yield and low purity of sodium bicarbonate, sodium chloride, sodium sulfate or a mixed salt of sodium chloride and sodium sulfate is used as a raw material and is subjected to double decomposition reaction with ammonium bicarbonate. After the reaction is finished, a sodium bicarbonate crude product and mother liquor are obtained through solid-liquid separation, sodium bicarbonate precipitation of the mother liquor is further promoted by adding a salting-out agent into the mother liquor, then the yield of sodium bicarbonate is increased, the used salting-out agent can be recycled, and the purity of the sodium bicarbonate product is improved in a washing mode. According to the method for improving the yield and purity of sodium bicarbonate prepared from sodium chloride / sodium sulfate, a feasible scheme is provided for resource utilization of industrial waste salt and high-salt wastewater.

The following relates generally to systems and methods for using chemical reactions, electrodialysis of cation-containing brines, such as NaCl and biogenic carbon dioxide sources, such as seawater, to create net-zero cation carbonates, such as soda ash, and / or carbon dioxide gas with an acid such as HC1 as byproduct for sales and / or further use.

The utility model discloses a system for producing sodium carbonate by using carbon dioxide and carbide slag in boiler flue gas, which is characterized in that the boiler flue gas discharged by a coal-fired boiler is purified and then enters a carbonization tower instead of part of lime kiln gas to react with ammoniacal salt water to generate NaHCO3, the NaHCO3 is calcined to generate a final product sodium carbonate, carbon is fixed to the final product, and the emission of CO2 is reduced; and meanwhile, the consumption of CO2 generated by calcining the limestone is reduced, so that the consumption of the limestone and the coke is greatly reduced. Calcium carbide slag generated by a calcium carbide method PVC production device is ground and screened to obtain coarse powder, fine powder and superfine powder, the coarse powder, the fine powder and the superfine powder are mixed in proportion to obtain a calcium carbide slag powder mixture with reasonable grain size distribution, the mixture is used for preparing lime milk, lime milk meeting the ammonia distillation requirement of a sodium carbonate system can be prepared without adding quick lime, the lime milk is used for the ammonia distillation system, and the production cost is reduced. Lime milk notches caused by reduction of lime yield are supplemented, and meanwhile, the utilization value of the solid waste carbide slag is improved.

The present invention provides a method and device system for preparing sodium carbonate and / or sodium bicarbonate and co-producing ammonium sulfate from sodium-based wastewater. According to the phase equilibrium law of a multi-component water-salt system, through the regulation of crystallization kinetics and supersaturation, the sodium-based wastewater does not need to be evaporated and crystallized to produce sodium sulfate solid. Instead, the wastewater after simple pretreatment is directly treated to achieve gradient crystallization separation of sodium sulfate, ammonium sulfate and sodium bicarbonate, thereby obtaining high-quality sodium bicarbonate, sodium carbonate and ammonium sulfate products.

The invention relates to the technical field of chemical equipment, and discloses a sodium carbonate production system adopting an ammonia-soda process. The system for producing sodium carbonate by the ammonia-soda process comprises a thin liquid distillation tower and a flash evaporation module. The thin liquid distillation tower is used for discharging waste thin liquid; the flash evaporation module comprises a second flash evaporation device and a water injection assembly; a steam outlet of the second flash tank is communicated with a steam inlet of the thin liquid distillation tower; the water inlet end of the water injection assembly is communicated with the thin liquid distillation tower, and the water outlet end of the water injection assembly is located in the second flash tank and used for discharging waste thin liquid to flush flash steam in the second flash tank. According to the invention, by arranging the water injection assembly, the waste thin liquid discharged from the thin liquid distillation tower is introduced into the second flash tank for flushing flash steam in the second flash tank so as to flush away droplets in the flash steam, and the content of calcium ions introduced into the thin liquid distillation tower can be reduced, so that the calcium ions in the waste thin liquid are reduced and even eliminated; and the waste thin liquid discharged from the thin liquid distillation tower can be used as filtering washing water.

The present invention provides a method for preparing soda ash or baking soda by resource utilization of coal chemical concentrated brine, the method comprising: removing harmful impurities from coal chemical concentrated brine by induced crystallization, acidolysis and thermally stimulated oxidation to obtain mixed salt and mixed salt mother liquor; separating sodium nitrate from the mixed salt mother liquor, double decomposing and evaporating the mixed salt, ammonium chloride mother liquor and ammonium sulfate mother liquor to obtain sodium sulfate mixed crystals and ammonium chloride enriched solution; obtaining ammonium chloride and ammonium chloride mother liquor from the ammonium chloride enriched solution; dissolving and salting out the sodium sulfate mixed crystals and sodium bicarbonate mother liquor to obtain a saturated sodium sulfate solution and crude ammonium sulfate; obtaining ammonium sulfate and ammonium sulfate mother liquor from crude ammonium sulfate; double decomposing the saturated sodium sulfate solution and ammonium bicarbonate to obtain a sodium bicarbonate product and a sodium bicarbonate mother liquor. The method provided by the present invention obtains baking soda and co-produces high-value ammonium salt products from coal chemical concentrated brine in a short process and at a low cost, thereby realizing the reduction, harmlessness and resource utilization of coal chemical wastewater.

A method for producing soda ash from flue gases involves capturing and processing the gases to remove contaminants and produce a high-purity soda ash. The process involves passing flue gas through a carbon capture system, where nitrates and sulfates are removed from the gas. The gas is then scrubbed with a rich caustic, causing a chemical reaction that removes carbon dioxide. The resulting product is then separated into a purified Na2CO3 product, essentially pure soda ash.

The present invention belongs to the technical field of utilization of hazardous wastes in environmental protection treatment, and particularly relates to a method for producing sodium bicarbonate and ammonium chloride from industrial waste salts. The present invention provides a method for resourcefully producing sodium bicarbonate and ammonium chloride from industrial waste salts. The regenerated sodium chloride is prepared by using the ash water obtained from the gasification and detoxification treatment of industrial waste salts. Then, taking the regenerated sodium chloride and ammonium bicarbonate as raw materials, and the ash water generated in the detoxification process as supplementary water, sodium bicarbonate (sodium bicarbonate) and ammonium chloride are generated through a double decomposition reaction. The present invention utilizes the high-temperature gasification and detoxification process, which not only solves the problem of resource utilization of industrial waste salts, but also reduces the limitation of the double decomposition reaction on the raw material sodium chloride, no longer being limited to industrial sodium chloride as the raw material. Moreover, the process flow is optimized, enabling the utilization rate of industrial waste salts to reach 100%, and the yield of sodium bicarbonate to reach 88.35%.

The present application relates to the technical field of ammonia compound preparation, in particular to a method for preparing ammonium sulfate and co-producing sodium bicarbonate by using sodium sulfate, comprising the following steps: mixing industrial-grade liquid ammonia with deionized water to prepare ammonia water with a free ammonia concentration of 60-120 ti (ti is the abbreviation of titer, which is 1 / 20 mol / L), controlling the temperature of the mixing process to be less than or equal to 40 DEG C to avoid ammonia volatilization, pre-carbonizing by passing in CO2 under the conditions of 20-70 DEG C and a carbon dioxide pressure of 0.1-0.6 MPa, and adding sodium sulfate or a mixture of sodium bicarbonate and mirabilite to obtain a pre-carbonized liquid. The present application adopts an integrated process of pre-carbonization, clarification, carbonization, ammonia separation and low-temperature crystallization, and ammonia evaporation circulation, and can be operated continuously or intermittently, has low industrial implementation difficulty, strong running stability, separates ammonium sulfate by using ammonia separation and low-temperature crystallization technology, replaces the traditional evaporation and concentration process, combines material recycling design, and reduces the energy consumption per unit product compared with the traditional process.

The invention discloses a method for preparing large-particle sodium bicarbonate from sodium sulfate. The method comprises the following steps: pretreating raw materials; dynamically adjusting reaction conditions; establishing a raw material database; carrying out multistage continuous crystallization reaction; heat integration and waste heat recovery; the alkali medium is recycled; the temperature gradient design is simplified; double salt crystal separation and resource utilization, and bicarbonate radical concentration control; strengthening double salt separation by a membrane separation technology; and carrying out solid-liquid separation and product collection. In a sodium sulfate raw material dissolving stage, sodium carbonate or sodium bicarbonate is added to adjust the concentration of carbonate in a solution, so that the concentration is stabilized in a target range, ATR FT-IR is used for carrying out in-situ real-time quantitative analysis on carbonate ions in an aqueous solution, carbonate is automatically supplemented through feedback control, and the content of carbonate ions in the aqueous solution is determined. A plate heat exchanger is installed in a multi-stage reaction device, waste heat of previous-stage reaction liquid is utilized to preheat next-stage reaction liquid, and heat in mother liquor is recovered by adopting a vacuum evaporation technology in salting-out crystallization.

The present disclosure relates to new methods and processes of byproduct conversion, wastewater remediation, byproduct upcycling / recycling, and sustainable cyclic methods thereof.

According to the present invention, there is provided a process for converting the lithium of a lithium-containing mineral into soluble form, as well as the use of the lithium-containing slurry or solution obtained from said process in the preparation of crystals of a solid lithium compound.

The invention belongs to the technical field of mineral product processing, and discloses a method for producing crude oil and sodium carbonate from oil-alkali paragenic ore. Comprising the steps of three-phase separation, dehydration, sedimentation, cyclone separation, filtration and purification. After being treated by the treatment method disclosed by the invention, the produced petroleum and sodium carbonate both meet the quality index requirements.

This invention relates to the field of terephthalic acid oxidation residue technology, specifically a high-efficiency treatment method for terephthalic acid oxidation residue, comprising the following steps: S1. Pretreatment; S2. Separation; S3. Evaporation and concentration; S4. Incineration; S5. Ash dissolution; S6. Filtration; S7. Sodium carbonate recovery; S8. Sodium carbonate recycling; S9. Bromine recovery and utilization; S10. Cobalt-manganese catalyst recovery; S11. Precipitate treatment; S12. Cobalt-manganese catalyst recycling. This application utilizes the waste heat or residual heat from the top of the xylene oxidation unit as a heat source to heat and concentrate the first filtrate. The acetic acid flash evaporator in the crystallizer serves as the heat source for evaporator V3 to evaporate and concentrate sodium carbonate, reducing process energy consumption and improving sodium carbonate recovery efficiency. The incineration unit heats the furnace body through external and internal incineration components, achieving efficient incineration of the material, greatly increasing the material's heating efficiency, and improving incineration efficiency and energy utilization.

The present application discloses a method for producing sodium carbonate and high-strength gypsum by using calcium carbonate and sodium sulfate as raw materials. In the present application, two low-value-added salts, sodium sulfate and calcium carbonate, are used as raw materials, and are combined with an ammonia cycle to produce a high-value-added product, i.e., sodium bicarbonate or sodium carbonate, and high-strength gypsum; by means of a calcium-oxide-based deamination unit, full cycling of an ammonia raw material in a production process is realized; and by producing the high-strength gypsum, the economic efficiency of the process is improved. The method provided in the present application has the advantages of a simple process, stable operation, low investment and low production costs.

Provided are a carbon dioxide capture system and capture method enabling simple and efficient capture of low concentrations of carbon dioxide in the atmosphere at reduced energy consumption. This carbon dioxide capture system comprises: a liquid supply unit for an alkaline aqueous solution; and a medium which is made of an air-permeable fibrous substance or porous substance and into the interior of which the alkaline aqueous solution supplied from the liquid supply unit penetrates and diffuses. The medium is arranged so as to be in contact with a natural wind-powered airflow. Carbon dioxide in the air is captured as carbonate generated by a reaction between the carbon dioxide and the alkaline aqueous solution which make contact in the medium interior. This carbon dioxide capture method comprises: bringing the aforementioned medium into contact with the natural wind-powered airflow; and supplying the alkaline aqueous solution, causing the alkaline aqueous solution to penetrate and diffuse into the medium interior, and thereby capturing the carbon dioxide in the air as carbonate generated by the reaction between the carbon dioxide and the alkaline aqueous solution that make contact in the medium interior.

The utility model discloses a sodium alkali method desulfurization absorbent regeneration and resource utilization system, which is characterized in that an ammonia water storage tank is connected to a carbonization tower, ammonia water is utilized to capture carbon dioxide in desulfurized flue gas to generate ammonium bicarbonate, and then the ammonium bicarbonate and an absorbent in a desulfurization absorption tower are regenerated to generate sodium bicarbonate and ammonium sulfate; sodium bicarbonate is prepared into a solution through the absorbent preparation tank and returns to the absorption tower, absorbent regeneration is achieved, absorbent regeneration mother liquor is evaporated and crystallized through the first-stage evaporation crystallization device and the second-stage evaporation crystallization device, and an ammonium sulfate byproduct is separated. According to the system disclosed by the utility model, the regeneration of the absorbent is realized through the backflow type connection between the devices, and the resource utilization of a sodium-alkali desulfurization product is realized.

The present invention relates to a process for the recovery of waste materials by producing soda ash, sodium hydroxide and hydrogen via converting the liquid and solid wastes, which are generated as a result of production from the Trona ore using solution mining and underground production methods, into a solution; and a process that will enable production in brine production areas that are currently not suitable for production.

The invention relates to a method for preparing a water mist fire extinguishing agent by washing fly ash with composite potassium salt. The method comprises the following steps: 1) a fly ash pretreatment module: carrying out vacuum pyrolysis on fly ash to obtain pyrolyzed fly ash; mixing the pyrolytic fly ash with hydrochloric acid, and carrying out solid-liquid separation to obtain fly ash washing liquid; adding a chelating agent into the fly ash washing liquid to obtain a first solution; adding a sodium carbonate solution into the first solution, and separating after heating reaction to obtain a second solution; 2) a potassium bicarbonate and sodium bicarbonate composite dry powder purification module: mixing the second solution, ammonia water and an organic alcohol solution, introducing carbon dioxide, stirring and reacting, filtering, cleaning and drying to obtain a sodium bicarbonate and potassium bicarbonate mixed solid; and 3) a potassium acetate and sodium acetate composite fire extinguishing agent preparation module: mixing the mixed solid of sodium bicarbonate and potassium bicarbonate with acetic acid.According to the invention, a novel low-cost water mist additive is prepared by compounding a plurality of alkali metal salts contained in the fly ash washing liquid and a plurality of salts in a fly ash system.

The invention relates to the technical field of ammonia compound preparation, in particular to a method for preparing ammonium sulfate and co-producing sodium bicarbonate by using sodium sulfate, which comprises the following steps: mixing industrial liquid ammonia with deionized water to prepare ammonia water with the free ammonia concentration of 60-120ti (ti titer abbreviation, namely 1 / 20mol / L), and controlling the temperature to be less than or equal to 40 DEG C in the mixing process to avoid ammonia volatilization, cO2 is introduced for pre-carbonization under the conditions that the temperature is 20-70 DEG C and the pressure of carbon dioxide is 0.1-0.6 MPa, sodium sulfate or a mixture of mirabilite and sodium bicarbonate is added, and a pre-carbonization solution is obtained; the process adopts an integrated process of pre-carbonization, clarification, carbonization, ammoniation low-temperature crystallization and ammonia distillation circulation, can be continuously or intermittently operated, is low in industrial implementation difficulty and high in operation stability, separates ammonium sulfate through an ammoniation and low-temperature crystallization synergistic technology, replaces a traditional evaporation and concentration process, is combined with a material cyclic utilization design, and has a good industrial application prospect. The unit product energy consumption is reduced compared with the traditional process.

The invention relates to a production method and device for preparing ammonium / alkali through a microreactor, and belongs to the technical field of safety, environmental protection, energy conservation and water conservation. The method comprises the following steps: simultaneously feeding a saturated aqueous solution of sodium chloride and a sodium bicarbonate solution into a mixing zone for premixing, and feeding into a reaction zone for reaction through shunting to obtain a reaction mixed solution; crystallizing, filtering, washing and drying the reaction mixed solution to obtain sodium bicarbonate; performing crystallization, chemical sublimation, precipitation and recrystallization on the mother liquor obtained by filtering to obtain ammonium chloride, and recovering ammonia gas generated in the crystallization, chemical sublimation, precipitation and recrystallization processes of the mother liquor; calcining the sodium bicarbonate to obtain sodium carbonate, and recovering carbon dioxide released in the calcining process; the recovered ammonia gas, carbon dioxide and water are prepared into a sodium bicarbonate solution to be used as a reaction base solution. According to the invention, liquid-gas reaction is improved into liquid-liquid reaction, and the microreactors connected in series and in parallel are improved, so that the yield and purity of the product are improved.

The invention belongs to the technical field of mirabilite resource utilization, and particularly relates to a mirabilite resource utilization method based on micro-nano bubble enhanced mass transfer. The method comprises the following steps: (1) dissolving mirabilite solid waste with water or carrying out concentration treatment on mirabilite waste water to enable the concentration of sodium sulfate to be close to a saturated state so as to obtain a mirabilite solution; (2) firstly introducing ammonia gas in a micro-nano bubble form into the mirabilite solution in the step (1) to form a sodium sulfate solution system rich in dissolved ammonia, and then continuously introducing carbon dioxide in the micro-nano bubble form to carry out a crystallization precipitation reaction; (3) carrying out solid-liquid separation on the reaction material in the step (2), and washing and drying the solid phase to obtain a sodium bicarbonate product; adding sulfuric acid into the liquid phase to react to convert the dissolved sodium bicarbonate into sodium sulfate, then performing concentration-crystallization treatment on the solution to obtain an ammonium sulfate crystal product, and recycling the residual mother liquor in the step (1). According to the method, a high-purity sodium bicarbonate product and a high-purity ammonium sulfate product can be simultaneously obtained through a simple process.

The present invention discloses a device for separating sodium bicarbonate from mother liquor in a soda ash production process, and relates to the technical field of separation devices. The device comprises a tower body, wherein a first feed pipe and a second feed pipe are respectively provided on the upper portion of the tower body from left to right, a reaction chamber is provided in the tower body, a separation chamber is provided at the bottom of the reaction chamber, a discharge pipe is provided at the upper portion of the separation chamber, a group of floats are provided at the bottom of a bucket-shaped screen, the bottom of one end of the discharge pipe is close to the upper edge of the bucket-shaped screen, a guide pipe is provided at the bottom of the guide pipe, a group of connecting pipes are provided at the bottom of the connecting pipe, a discharge pipe is provided at the bottom of the connecting pipe, the discharge pipe passes through the bottom of the tower body, the guide pipe and the connecting pipe are connected by a rotary joint, the connecting pipes are connected by a rotary joint, and the connecting pipe and the discharge pipe are connected by a rotary joint. The present invention solves the technical problems of existing equipment for separating sodium bicarbonate crystals from ammonium chloride mother liquor, such as the large number of equipment, high investment, high maintenance cost, high power consumption, and cumbersome operation.