69results about "Preparation from chlorides" patented technology

The embodiment of the invention relates to the field of separation by using a physical or chemical method, in particular to chloride molten salt purification equipment and a purification method. The chloride molten salt purification equipment comprises a containing part maintaining assembly, a purification furnace body, a purification furnace cover body, a furnace cover movement mechanism and a purification moving assembly. The accommodating part holding assembly is used for holding a plurality of molten salt accommodating parts; the purification furnace cover body is used for opening or closing a top opening of the purification furnace body and forms a reaction space together with the purification furnace body; the furnace cover movement mechanism is used for driving the purification furnace cover body to lift and rotate, so that the top opening is completely opened or closed; the purification moving assembly is used for driving the containing part maintaining assembly to move in the reaction space, and when the top opening is completely opened, the purification moving assembly drives the containing part maintaining assembly to move to protrude out of the top opening. According to the chloride molten salt purification equipment provided by the embodiment of the invention, the discharging efficiency and the feeding efficiency of the chloride molten salt after the chloride molten salt is purified can be improved.

The present application relates to a kind of catalyst for hydrogen chloride oxidation preparation chlorine and its preparation method and application.The preparation method includes: after carrier substrate, metal tantalum powder, binder solution are mixed, extrusion forming is obtained green body, the green body is prepared composite carrier by calcination, the mass fraction of metal tantalum powder in the composite carrier is 5%-30%;Inorganic salt containing catalytically active element is made into solution and is placed in the composite carrier, and after drying, pre-product is obtained, and the pre-product is prepared catalyst by calcination.The preparation method described in the present application prepares high thermal conductivity composite carrier, not only effectively improves the heat conduction efficiency of catalyst, guarantees the effective activity of catalyst, but also guarantees the stability of composite carrier, thereby effectively prolongs the life of catalyst.

The invention discloses a hydrogen chloride gas absorption device-modified double-path pure water absorption system and a process method, and relates to the technical field of chemical waste gas treatment and resource recovery. The device comprises a hydrochloric acid synthesis furnace, a first-stage falling film absorber, a second-stage falling film absorber, a combined tail gas absorption tower and a tail gas purification unit which are sequentially connected, as well as a pure water supply system and an automatic control system. The system is characterized in that the pure water supply system is divided into two independent branches through a water inlet header pipe to be connected to the combined tail gas absorption tower, and each branch is provided with an automatic regulating valve. According to the method, a traditional single-path water absorption system is transformed into a double-path standby system through low-cost technical improvement of an existing single-path absorption device, automatic and rapid switching to the other path when one path breaks down is achieved, and therefore the problems that in the prior art, production is discontinuous, product concentration fluctuation is large, and potential safety hazards exist are effectively solved; the effects of efficiently, continuously and safely producing high-concentration hydrochloric acid and realizing near-zero emission of tail gas are achieved.

The invention discloses a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, belongs to the technical field of synthesis of organosilicon compounds and high-purity electronic special gases, and discloses a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst. Comprising the following steps of S1, catalyst preparation, S2, methylsilane and hydrogen chloride preparation, S3, product purification and S4, activated carbon regeneration, 1-ethyl-3-methylimidazole aluminum chloride as the catalyst has good thermal stability and catalytic activity, the risk of catalyst inactivation is avoided, the catalyst can be pumped into a reaction kettle, the whole process is operated in a closed mode, and operation is easy. The method is safe, reliable and environment-friendly, and meanwhile, regeneration and recycling of the activated carbon bring a better use prospect.

The present invention relates to a process for producing isocyanates and, optionally, polyurethanes, by at least synthesizing (1) phosgene (20) from carbon monoxide (21) and chlorine (22); reacting (2) phosgene (20) with a diamine (23) to produce a diisocyanate (24) and hydrogen chloride (25); providing a carbon dioxide gas stream (31); and cleaning (4) the carbon dioxide gas stream (31) with additional components, wherein the carbon dioxide is converted by a RWGS reaction (6) to produce carbon monoxide (21) and hydrogen (29), which are used as raw materials for polyurethane production, and optionally reacting (3) the diisocyanate (24) with a polyether polyol (35a) and / or polyester polyol (35b) to produce polyurethane (37).

This invention provides a method for preparing a platinum-ruthenium catalyst for chlorine production, comprising: mixing nitrosylruthenium nitrate, platinum nitrate solution, deionized water, and a dispersant; heating to reflux temperature to dissolve; continuing the reaction at reflux temperature for 1 hour after the system changes from brownish-red to brownish-black; filtering the system after cooling to room temperature; and mixing the platinum-ruthenium mixture, silica hydrosol, and silica powder. The mixture is extruded into cylindrical pieces with a diameter of 5 mm, dried at 100-120°C for 6 hours to a breakage length of approximately 3-5 mm, and calcined in air at 200-240°C for 12 hours to obtain the platinum-ruthenium catalyst. This method can prepare a platinum-ruthenium catalyst with low chlorine impurity content that easily leads to catalyst aging. Simultaneously, because the reaction system remains acidic, the occurrence of ruthenium hydrolysis side reactions is reduced, resulting in a platinum-ruthenium catalyst with high yield, high ruthenium dispersion, and high catalyst activity.

The invention discloses a method for comprehensively recycling high and low boiling residues and waste acid in the production process of high-purity antimony, and relates to the field of non-ferrous metal metallurgy. The method comprises the following steps: mixing high and low boiling residues produced in the preparation process of high-purity antimony with waste acid produced by cleaning equipment, spraying the mixed solution into a roasting tower through compressed air for roasting, and enabling roasted flue gas to sequentially pass through a settling chamber, a bag collector and a two-stage water spraying absorption tower to respectively produce antimony white and hydrochloric acid, the produced antimony white can be directly sold or used as an antimony smelting raw material, and the byproduct hydrochloric acid can be used as an acid for wet smelting or can be further concentrated into 35-38% concentrated hydrochloric acid. The method can realize gradient recycling of antimony and chlorine elements in the high and low boiling residues and the waste acid, has the characteristics of high resource utilization level and no generation of a large amount of wastewater, and has good economic value and environmental protection benefit.

The utility model relates to the technical field of chemical gas recovery, and provides a device for separating trichlorosilane tail gas and co-producing fumed silica, which adopts a combined process to treat the trichlorosilane tail gas and is provided with a rectification separation seat provided with a low-temperature cold energy recovery mechanism. Hydrogen, hydrogen chloride and chlorosilane in the tail gas are separated step by step through the rectification separation assembly, the hydrogen chloride and the chlorosilane are directly conveyed to the combustion assembly, the purity of the hydrogen chloride is recycled to the trichlorosilane tail gas treatment assembly, recycling after separation is achieved, and the purposes of further saving energy consumption and improving the purity are achieved; a fumed silica combustion furnace suitable for low-boiling-point chlorosilane is adopted, so that the chlorosilane and hydrogen are mixed and combusted to generate fumed silica and hydrogen chloride, and the fumed silica can be directly discharged through a fumed silica discharge pipe; and the generated hydrogen chloride is recovered into the trichlorosilane tail gas treatment seat through a second hydrogen chloride return pipe, and closed-loop utilization is realized.

The utility model discloses a multifunctional chemical experiment device, which belongs to the technical field of teaching aids and comprises a main body, the main body comprises a three-neck cylindrical flat-bottomed flask, a bottle cavity is arranged in the three-neck cylindrical flat-bottomed flask, and three groups of distributed open piles are arranged on the top surface of the three-neck cylindrical flat-bottomed flask. According to the property verification device, experiment operation and teaching processes are carried out through the bottle cavity in the three-neck cylindrical flat-bottomed flask, heating is not needed in the gas preparation process, the acid amount is controlled at any time, the pressure intensity generated by Cl2 can be automatically adjusted through the balloon communicated with the top surface of the three-neck cylindrical flat-bottomed flask, the safety coefficient is high, and the experiment efficiency is high. Redundant Cl2 in the experiment process can be automatically absorbed by soda lime in the balloon and can also be absorbed by injecting a sodium hydroxide solution through the glass charging valve, so that the operation is more convenient, the whole experiment is performed in a sealed environment, the mouth part is polished, the sealing performance is good, the environment is protected, the Cl2 can be effectively prevented from polluting the environment, and the environmental awareness of students is enhanced.

This invention discloses an apparatus for producing hydrogen chloride from carbon tetrachloride, belonging to the field of hydrogen chloride process technology. It aims to solve the problem in existing technologies where the reaction of carbon tetrachloride with water produces toxic phosgene if too little water is used, and hydrogen chloride and carbon dioxide gases are produced if too much water is used. Since the boiling points of these two gases are very close at atmospheric pressure, separation is difficult. The apparatus includes a carbon tetrachloride storage tank and a pure water tank, each equipped with a heater. A first valve is installed on the carbon tetrachloride storage tank, and a second valve is installed on the pure water tank. The carbon tetrachloride storage tank is connected to a first heat exchanger, which is connected to a first gas pump. The pure water tank is connected to a second heat exchanger, which is connected to a second gas pump. The second and first gas pumps are connected to a mixing mechanism, which is connected to a tubular hydrolysis reactor. A concentrated sulfuric acid contact tower is connected to the tubular hydrolysis reactor.

The invention discloses a CeO2 loaded Fe-B catalyst as well as preparation and application thereof. The CeO2 loaded Fe-B catalyst is prepared by a preparation method comprising the following steps: (1) loading ferric salt on a CeO2 carrier by wet impregnation, then drying and calcining in a nitrogen atmosphere to obtain a calcined product, and dispersing the calcined product in water to obtain a dispersion liquid; and (2) under the protection of nitrogen, dropwise adding a boron-alkali mixed solution into the dispersion liquid, stirring to react, separating, washing and drying the generated precipitate after the reaction is finished, and finally calcining the dried product under the protection of nitrogen to obtain the CeO2 loaded Fe-B catalyst. The invention provides application of the CeO2-loaded Fe-B catalyst in preparation of chlorine by catalytic oxidation of hydrogen chloride. By optimizing the preparation process, the catalyst has excellent activity and stability, so that the efficiency of converting HCl into Cl2 is greatly improved, and meanwhile, the cost and the environmental burden are reduced.

This invention relates to a catalytic membrane for HCl oxidation reaction, the preparation method of which includes: Step 1: reacting silica particles with SiO2. ­2 A mixture of ZrO2 sol and silica gel is coated onto a hollow fiber carrier and calcined to obtain a transition layer for the membrane. Step two: A silsesquioxane sol is applied to the transition layer obtained in step one and calcined to obtain a silica membrane. Step three: The silica membrane obtained in step two is subjected to impurity removal treatment. Step four: A solution of silane coupling agent (A) and a metal salt solution (B) are prepared separately and mixed to obtain solution C. The silica membrane treated in step three is immersed in solution C and grafted with nano-metal particles using ultrasonic assistance, followed by a high-temperature reaction to obtain a catalytic membrane. The catalytic membrane designed in this invention, when applied to the HCl oxidation reaction, can separate reactants and products simultaneously, causing the reaction to shift forward, increasing the reaction conversion rate, reducing the reaction temperature, and extending the catalyst lifetime.

The present application relates to the technical field of chemical synthesis, and particularly relates to a preparation method of 4,4'-difluorobenzophenone and a method for synthesizing polyether ether ketone by two steps of carbon tetrachloride. The preparation method of 4,4'-difluorobenzophenone comprises the following steps: under the condition that trifluoromethanesulfonic acid and N-methyl pyrrolidone exist, CCl4 and fluorobenzene are reacted, and the product is hydrolyzed to obtain 4,4'-difluorobenzophenone. The present application solves the problems of high cost, poor environmental protection and performance that cannot meet market requirements of PEEK by innovating raw material route, catalytic system and process parameters, realizes low-cost, green and high-performance synthesis of PEEK, the purity of the prepared DFBP monomer can reach >=99.99%, and the PEEK molecular weight distribution (PDI<=1.9) can be narrowed, and the method is suitable for industrialized production of PEEK materials used in high-end fields such as aerospace, medical devices and electronic and electrical appliances.

The invention relates to the field of fluorine-containing organic matter treatment, in particular to a fluorine-containing organic matter treatment method, a fluorine-containing organic matter-containing hydrogen chloride purification method, a chlorine preparation method and a metal fluoride preparation method. The treatment method of the fluorine-containing organic matter comprises the steps that in the presence of hydrogen chloride, the fluorine-containing organic matter makes contact with a metal compound, metal fluoride is generated, and L acid exists in the metal compound under the action of hydrogen chloride. Therefore, the fluorine-containing organic matters in the hydrogen chloride can be effectively removed, so that the hydrogen chloride is purified and is further used for preparing chlorine, and meanwhile, the fluorine-containing organic matters in the hydrogen chloride can also be converted into metal fluorides with high additional value, such as aluminum fluoride.

The utility model discloses a dry hydrogen chloride preparation device and belongs to the technical field of pharmaceutical chemical production devices and gas generation. The device is formed by combining and connecting a concentrated sulfuric acid head tank, a pressure balancer, a hydrogen chloride generator, a settler, a gas guide pipe, a dryer, a gas flow disperser, a buffer tank, a dry hydrogen chloride outlet, a tail gas treatment control valve and the like, the main technical innovation points comprise three aspects: 1, a pressure balancer is additionally arranged between a concentrated sulfuric acid dripping head tank and a hydrogen chloride generator, 2, a settler is designed and additionally arranged at a hydrogen chloride airflow outlet, and 3, a concentrated sulfuric acid dryer is designed and additionally arranged; the dry hydrogen chloride preparation device provided by the technical scheme of the utility model effectively meets the requirements on dry hydrogen chloride gas in raw material medicines and chemical production processes, and has the advantages that the dry hydrogen chloride gas can be prepared at any time as required and dangerous gas raw materials are not stored; the method also has the characteristics of high hydrogen chloride purity, safe process and convenient operation.

The invention discloses a preparation method and application of a high-dispersion ruthenium-based catalyst. According to the disclosed scheme, a ruthenium precursor solution and carrier mixture system is treated by adopting a microwave hydrothermal method; the ruthenium oxide is gradually separated out from the precursor solution under the microwave hydrothermal condition and is uniformly loaded on the carrier; and finally, centrifuging, washing, drying and roasting to obtain the high-dispersion ruthenium-based catalyst. The catalyst is applied to hydrogen chloride catalytic oxidation reaction and shows good catalytic activity and stability. By organically combining a microwave field and a hydrothermal field, controllable synthesis of the ruthenium-based catalyst with high dispersion, small particle size and narrow distribution is realized. Meanwhile, the molecular vibration of the polar solution is accelerated under the microwave condition, the solution-carrier interface structure is obviously influenced, certain defects can be easily generated on the surface of the carrier, the directional anchoring of the ruthenium component is promoted in combination with the hydrothermal environment, and finally the stability of the ruthenium-based catalyst is easily improved.

The embodiment of the invention relates to the field of separation by using a physical or chemical method, in particular to chloride molten salt purification equipment and a chloride molten salt purification method. The chloride molten salt purification equipment comprises a containing part maintaining assembly, an oxygen supply assembly, a purification furnace body and a purification moving assembly. The accommodating part holding assembly is used for holding a plurality of molten salt accommodating parts; the oxygen supply assembly is used for supplying oxygen to the molten salt containing pieces and comprises a plurality of oxygen supply pipe fittings; the purification furnace body is arranged to form a reaction space capable of adjusting the temperature and containing the fused salt containing part, and oxygen supply through holes allowing the multiple oxygen supply pipe fittings to enter the reaction space are formed in the purification furnace body; and the purification moving assembly is used for enabling the plurality of fused salt accommodating pieces to be aligned with the plurality of oxygen supply pipe fittings respectively and driving the accommodating piece keeping assembly to move in the reaction space. The chloride molten salt purification equipment provided by the embodiment of the invention is beneficial to improving the purification efficiency of the chloride molten salt.

A heat medium storage apparatus 10 including a heat medium tank defining an airtight inside space 22 and a preheating device 30 including a temperature adjusting portion 32 capable of melting the heat medium in solid form, wherein the temperature adjusting portion has a first part 32a and a second part 32b,when the temperature adjusting portion is provided so as to extend in the inside space, the first part is in contact with the heat medium so as to be covered with the heat medium, and the second part is provided so as to protrude into a gap area in which the heat medium is absent in the inside space and thereby the second part is exposed, and when the temperature adjusting portion is provided so as to extend in contact with the outer surface of the heat medium tank, the temperature adjusting portion extends in a contact manner so as to stretch from a first area corresponding to an area in contact with the heat medium in the inside space to a second area corresponding to an area not in contact with the heat medium in the inside space, the areas forming the outer surface of the heat medium tank, the first part being in contact with the first area, the second part being in contact with the second area.

This invention discloses a method for the comprehensive utilization of calcium and magnesium solution and CO2, comprising the following steps: S11: using high-salt calcium and magnesium wastewater and CO2 tail gas as raw materials, the high-salt calcium and magnesium wastewater contains CaCl2 and MgCl2, water-soluble amine is added to the high-salt calcium and magnesium wastewater and mixed, and CO2 tail gas is introduced to carry out a mineralization reaction, generating calcium carbonate precipitate, water-soluble amine hydrochloride and magnesium bicarbonate; S12: solid phase calcium carbonate is obtained by solid-liquid separation, oil-soluble amine is added to the separated liquid phase, HCl in the water-soluble amine hydrochloride is extracted, the water-soluble amine is regenerated, and oil-soluble amine hydrochloride and magnesium carbonate trihydrate precipitate are generated; S13: after phase separation, the aqueous phase is separated by solid-liquid separation to obtain liquid phase water-soluble amine and solid phase magnesium carbonate trihydrate, and the oil-soluble amine hydrochloride in the oil phase is pyrolyzed to obtain regenerated oil-soluble amine and HCl gas. This invention utilizes a water / oil dual-phase amine-enhanced calcium-magnesium solution mineralization CO2 and an extraction-pyrolysis synergistic regeneration cycle process to achieve harmless treatment and resource utilization of both calcium-magnesium-containing high-salt wastewater and CO2 tail gas.

The present application relates to hydrogen chloride purification technical field, especially to a kind of production electronic grade hydrogen chloride and the method and system of byproduct chemical grade hydrogen chloride and industrial grade hydrogen chloride.It is formed green environmental protection's circular economy by optimizing process flow, using chlorobenzene tail gas as raw material to produce electronic hydrogen chloride and chemical grade hydrogen chloride and industrial grade hydrogen chloride, and equipment investment cost is low, process production cost is low, market prospect is broad.The production process of the present application has no three wastes discharge, and the recovery rate of chlorobenzene is improved by returning the recovered mother liquor to the chlorobenzene production system;The recovery rate of main products electronic hydrogen chloride, chemical grade hydrogen chloride and industrial grade hydrogen chloride reaches 52%;After hydrogen chloride containing light components is absorbed by water, byproduct hydrochloric acid can be obtained;The light components discharged are nitrogen, oxygen and carbon dioxide, which do not pollute the environment;Chlorobenzene tail gas can be fully recycled.

The invention discloses a method and device for preparing ferric oxide from ferric trichloride, and the method comprises the following steps: carrying out sectional heating gasification on a ferric trichloride solid raw material to obtain ferric trichloride gas, and the sectional heating comprises first-section heating (350-400 DEG C), second-section heating (400-500 DEG C) and third-section heating (500-650 DEG C) which are connected in sequence; the ferric trichloride gas and oxygen are subjected to an oxidation reaction, the molar ratio of the ferric trichloride gas to the oxygen is larger than or equal to 4.4: 3, and an iron oxide product and mixed gas are obtained; and condensing and separating the mixed gas to obtain chlorine and ferric trichloride products. According to the method, the technical breakthrough of'preparing high from low 'is achieved through the synergistic effect of'segmented gradient gasification + excess ferric trichloride', the device gasifies ferric trichloride through the segmented heating furnace, gasification of ferric trichloride and impurity separation are effectively controlled, high-purity ferric oxide is prepared, and meanwhile high-purity ferric trichloride and high-purity chlorine are produced as by-products.

A fixed bed reactor for preparing chlorine by oxidizing hydrogen chloride relates to the field of chlorine preparation devices and comprises a reactor body, a feed port is arranged on the upper portion of the reactor body, and a discharge port is arranged on the lower portion of the reactor body. The reactor body is in a vertically-arranged long-strip-shaped tube shape, a lower end opening of the reactor body is the discharging opening, a sieve plate is arranged at the discharging opening, a temperature adjusting jacket is arranged on the outer side of the reactor body, the upper end and the lower end of the reactor body extend out of the upper end and the lower end of the temperature adjusting jacket, and a heat conduction oil outlet is formed in the upper end of the temperature adjusting jacket. A heat-conducting oil inlet is formed in the lower end part of the temperature-regulating jacket; and a sleeve-shaped anti-corrosion lining is arranged on the inner side of the reactor main body below the temperature-regulating jacket. The reactor has the advantages of simple structure, low cost and the like, and the bottom of the reactor main body is difficult to corrode by hydrochloric acid.

The carbon dioxide conversion system comprises a first mixing chamber, an electrochemical reactor, a first conversion unit and a second conversion unit, the feeding end of the first mixing chamber is suitable for introducing a to-be-reacted object and water; the discharge end of the first mixing chamber is communicated with the feed end of the electrochemical reactor, and the electrochemical reactor is configured to perform a water half-splitting reaction on water to generate hydroxyl ions and hydrogen ions, and respectively react with a to-be-reacted object based on the generated hydroxyl ions and hydrogen ions to generate a first product and a second product; the feeding end of the first conversion unit is communicated with the first discharging end of the electrochemical reactor, and the first conversion unit is configured to convert a first product generated by the electrochemical reactor; the feeding end of the second conversion unit is communicated with the second discharging end of the electrochemical reactor, and the second conversion unit is configured to capture carbon dioxide by using a second product generated by the electrochemical reactor and convert the carbon dioxide into a third product.

This invention discloses a catalyst support, a preparation method, and a catalyst for preparing chlorine gas. The catalyst preparation materials include a catalyst support and an aqueous solution of ruthenium trichloride. The catalyst support is rutile titanium dioxide containing oxygen vacancies, which is prepared by subjecting anatase titanium dioxide to high-temperature ultraviolet treatment in an inert atmosphere. The preparation method for the catalyst involves impregnating the ruthenium trichloride aqueous solution onto the oxygen-vacancy-containing rutile titanium dioxide using an equal-volume impregnation method, drying at 80–120°C for 6–24 hours, and then heating at 250–350°C in an oxygen or air atmosphere for 6–16 hours. This catalyst overcomes the shortcomings of existing technologies, exhibiting a high reaction rate at a relatively low reaction temperature (300°C), and achieving a hydrogen chloride conversion rate close to the hydrogen chloride equilibrium conversion rate.

The invention discloses a low-solid-waste-amount cooperative treatment method for incineration fly ash and flue gas, and relates to the technical field of waste incineration treatment and recycling. The low-solid-waste-amount cooperative treatment method comprises the following steps that ammonium sulfate salt is added and converted in the incineration process; fly ash collection and water-soluble filtration treatment; carrying out absorption treatment on the generated flue gas; and combining and recycling the obtained products. The ammonium sulfate salt is added in the incineration process, hydrochloride in the fly ash is converted into sulfate, meanwhile, the chlorine element is transferred into the flue gas in the form of hydrogen chloride, after the fly ash is dissolved in water and filtered, filtrate is crystallized to obtain a mirabilite product, and after the incineration flue gas is subjected to water absorption and alkali absorption treatment, a byproduct hydrochloric acid and a sodium sulfate solution are obtained respectively. The solution is reused in the fly ash dissolving process, harmlessness, reduction and recycling of the fly ash are achieved, and finally the purposes that the fly ash is greatly reduced, harmful substances are efficiently removed, by-products are recycled, and the treatment cost is remarkably reduced are achieved.

The invention discloses a Fe-B-based catalyst as well as preparation and application thereof. The Fe-B-based catalyst is prepared by the preparation method comprising the following steps: adding a boron-alkali mixed solution into a ferric salt solution in an ice-water bath under a protective atmosphere, fully stirring and reacting, separating, washing and drying the generated precipitate under the protective atmosphere, and finally calcining for 3-6 hours at 500-600 DEG C under the protective atmosphere to obtain the Fe-B-based catalyst, the boron-alkali mixed solution is prepared from a boron source reducing agent, strong alkali and water; the dosage ratio of the boron-alkali mixed solution to the ferric salt solution is 3-4 based on the molar ratio of boron to iron contained in the boron-alkali mixed solution to the ferric salt solution. The invention provides application of the Fe-B-based catalyst in preparation of chlorine gas through hydrogen chloride oxidation. By controlling the preparation method, the prepared Fe-B-based catalyst is particularly suitable for a reaction for preparing Cl2 through HCl oxidation, and shows high catalytic activity and stability.

The invention relates to a method for treating waste acid for pickling steel, in which the following steps are carried out: i. Mixing the waste acid with a sulfuric acid solution to obtain a reaction mixture comprising hydrochloric acid and ferrous sulfate in hydrated form, in which the reactants comprise 5 to 40 weight percent sulfuric acid; and ii. Subjecting the reaction mixture to distillation to obtain a distillate and a concentrate; iii. Mixing the concentrate with water such that the weight ratio between concentrate and water is from 0.1 to 10 to obtain an aqueous solution; iv. Setting the temperature of the aqueous solution to-10 DEG C to 50 DEG C to obtain a liquid phase and a solid phase; and v, separating the liquid phase and the solid phase obtained in the step iv.

The invention relates to the technical field of organic silicon chemical tail gas treatment and resource recovery, in particular to a production process for tail gas acid making, filter pressing and slag removal. The invention aims to solve the problem that the system is blocked by viscous slag generated by hydrogen chloride acid preparation and residual monomer hydrolysis in the phenyl trichlorosilane synthesis tail gas. Tail gas containing hydrogen chloride and phenyl trichlorosilane monomers is introduced into an absorption tower and makes contact with the functionalized modified absorption liquid, hydrogen chloride is absorbed to generate hydrochloric acid, and meanwhile the monomers are hydrolyzed; carrying out filter pressing on the generated slurry, and separating out viscous hydrolysis residues and a hydrochloric acid solution; the hydrolysis residues are subjected to plasma surface modification, a click chemical compatilizer is added, then the hydrolysis residues and pulverized coal are mixed and calcined, calcination tail gas is recycled, and solid products are recycled; and purifying the hydrochloric acid solution to obtain the product. According to the process, efficient removal and viscosity reduction of the hydrolysis residues are achieved, the recovery rate of hydrogen chloride exceeds 99.5%, the removal rate of the hydrolysis residues exceeds 99%, the problem of pipeline blockage is thoroughly solved, collaborative recycling of waste gas and waste residues is achieved, and the operation stability of the device is remarkably improved.

A method of preparing a calcium carbonate compound comprises (i) reacting urea with an enzyme and a precipitating compound, wherein the precipitating compound comprises or consists of calcium chloride, to yield calcium carbonate and ammonium chloride; (ii) reacting the ammonium chloride to yield hydrogen chloride and ammonium hydroxide or ammonia; (iii) performing a step comprising either (iii-a1) reacting a calcium- containing mineral with the hydrogen chloride to yield the calcium chloride, wherein the calcium-containing mineral comprises calcium silicate; and when step (ii) yields ammonium hydroxide then (iii-a2) degassing the ammonium hydroxide to yield ammonia; or (iii-b1) reacting a calcium-containing mineral with the ammonium hydroxide to yield calcium hydroxide and ammonia, wherein the calcium-containing mineral comprises calcium silicate, and (iii-b2) reacting the calcium hydroxide and the hydrogen chloride to yield the calcium chloride; (iv) reacting the ammonia produced in step (ii) or step (iii) with carbon dioxide to yield an ammonium salt, wherein the ammonium salt comprises or consist of one or more of ammonium carbamate, ammonium bicarbonate and ammonium carbonate; and (v) reacting the ammonium salt to yield the urea.