11results about "Cyanamide" patented technology

The application discloses a preparation method of monocyamine solution and belongs to the technical field of fine chemical industry. By optimizing the process conditions, especially adding new stabilizers of o-benzoquinone, 1,4-naphthoquinone and methylhydroquinone, the content of dicyandiamide in the monocyamine solution is reduced, and high-quality monocyamine with a concentration of 30% is produced at a lower temperature. The fine control technology of monocyamine low-temperature hydrolysis reaction developed by the application changes the prior art method, i.e. first hydrolyzing lime nitrogen in a hydrolysis kettle to produce monocyamine aqueous solution with a concentration of 18%, then concentrating through an evaporation system, and finally producing monocyamine finished product with a concentration of 30%. The application improves the product quality and reduces the product energy consumption through the "low-temperature one-step hydrolysis method" monocyamine production process without evaporation and concentration, so that the stable and green low-carbon production of high-grade monocyamine products is realized.

The present application relates to a kind of preparation method and application of recycled asphalt, waste modified asphalt waterproofing membrane is cut into cutting material by cutting machine, cutting material is put into special double screw extruder, and is converted into molten state recycled asphalt.The present application also utilizes layered silicate clay and biodegradable resin to modify recycled asphalt, for preparing recycled asphalt system modified asphalt or recycled asphalt containing waterproofing membrane, realizes the recycling of waste modified asphalt waterproofing membrane, especially for the recycling of waste modified asphalt waterproofing membrane containing polyester fiber, recycled asphalt system modified asphalt prepared by recycled asphalt can also reduce the dependence on petroleum chemical composition-artificial synthetic rubber required for traditional modified asphalt, and the preparation method of the present application also has the advantages of low energy consumption, little pollution, reduce carbon dioxide emissions and the like relative to existing recycling technology.

This invention belongs to the field of pharmaceutical chemical synthesis technology, specifically relating to a method for preparing high-yield dicyandiamide by urea pyrolysis. The method includes a reaction process using urea and alkaline earth metal oxides as raw materials in a sealed environment, wherein the reaction pressure is 0.1 to 0.3 MPa. Experiments show that by maintaining a positive pressure environment of 0.1 to 0.3 MPa in a dynamically sealed continuous rotary kiln, the volatilization loss of isocyanate (HNCO) is suppressed from a physical process perspective. This reduces the degree of escape of volatile isocyanate (HNCO) during pyrolysis and promotes its further reaction with the solid matrix (alkaline earth metal oxide matrix), thereby improving the raw material utilization rate and dicyandiamide yield. In particular, when the pressure in the dynamically sealed continuous rotary kiln is 0.2 MPa, the yield of the obtained dicyandiamide is 93.5% while maintaining a purity of 99.88%.

The application belongs to the technical field of catalytic preparation of formate from CO2, and particularly relates to a SnNCN catalyst, a preparation method and application of the SnNCN catalyst in electrocatalytic reduction of CO2. The preparation method comprises the following steps: (1) mixing a tin source and melamine, and obtaining an intermediate product after reaction; and (2) calcining. The preparation method overcomes the problem that the catalyst with an oxidation state metal active center in the prior art has poor stability when used in electrocatalytic reduction of CO2 under an industrial-grade current, and the oxidation state metal active center of the obtained catalyst can remain stable under long-time electrolysis conditions.

The invention discloses a method for preparing calcium cyanamide based on two-stage reaction of a rotary tube furnace, and relates to the technical field of inorganic chemical synthesis, and the method comprises the following steps: obtaining industrial urea and self-burning calcium oxide; the method comprises the following steps: uniformly mixing and grinding industrial urea and self-burning calcium oxide according to a mass ratio of 2: 1 to obtain a reaction precursor, and putting the reaction precursor into a rotary tube furnace; introducing high-pressure inert protective gas into the rotary tube furnace to replace air, controlling the rotary tube furnace to continuously rotate, and controlling the reaction precursor in the rotary tube furnace to react at the constant temperature of 240 DEG C for 2 hours to obtain a calcium cyanate intermediate; continuously introducing high-pressure inert protective gas into the rotary tube furnace, controlling the calcium cyanate intermediate in the rotary tube furnace to perform high-temperature reconstruction reaction for 2.0 hours at the temperature of 650 DEG C and the pressure of 2.2 MPa, and removing carbon dioxide to obtain a target calcium cyanamide product. According to the invention, a brand-new, more efficient, more environment-friendly and easier-to-industrialize calcium cyanamide production path is constructed.

The utility model relates to a cyanamide hydrolysis kettle cooling system which comprises a reaction kettle, an outer jacket is fixedly connected to the outer wall of the reaction kettle, a closed heat exchange cavity is formed between the outer jacket and the reaction kettle, a medium input pipe is arranged at the bottom of the heat exchange cavity, and a medium output pipe is arranged at the top of the heat exchange cavity; two first partition plates distributed up and down are fixedly connected into the cooling box, an inner cavity of the cooling box is divided into a cooling chamber, a filtering chamber and a water storage chamber from top to bottom in sequence through the two first partition plates, the cooling chamber is provided with a circulation input pipe, the medium output pipe is communicated with the circulation input pipe through a first water pump, and the water storage chamber is provided with a circulation output pipe; the medium input pipe is communicated with the circulating output pipe through a second water pump. The cooling medium exchanges heat with the reaction solution in the heat exchange cavity, enters the cooling box through the first water pump to be cooled, and then is conveyed into the heat exchange cavity again through the second water pump to exchange heat to form circulating heat exchange cooling, so that the cooling requirement in the cyanamide production process is met.

The invention provides a method for preparing synthesis gas by coupling ammonia gas with carbonate reaction, and belongs to the field of carbonate pyrolysis. The ammonia gas is used for replacing hydrogen to serve as a hydrogen source to be used for carbonate thermal decomposition, the hydrogen source is introduced to reduce the thermal decomposition temperature, meanwhile, hydrogen and carbon monoxide are generated in the decomposition process, carbonate and ammonia gas are coupled in the carbonate decomposition process, multiple functions of reduction, nitridation, hydrogen supply and the like are achieved, the reaction system is simplified, carbon dioxide emission is greatly reduced, and the production cost is reduced. In the decomposition process, no extra catalyst needs to be added, the reaction process is green, environment-friendly, safe and non-toxic, the operation in the decomposition process is simple, hydrogen does not need to serve as a reducing agent, and the safety of thermal decomposition is improved.

This invention belongs to the field of pharmaceutical chemical synthesis technology, specifically relating to a method for preparing pharmaceutical-grade dicyandiamide by urea pyrolysis. It includes a process for preparing a hydrogen-containing intermediate and a process for preparing dicyandiamide from the hydrogen-containing intermediate. The process for preparing the hydrogen-containing intermediate involves continuously co-feeding urea and alkaline earth metal oxides into a dynamically sealed reaction system at a molar ratio of 2.05:1.00 to 2.15:1.00, sequentially passing them through three hot zones to obtain a cyanide-containing intermediate. Experiments show that reasonable molar ratio control, combined with the three hot zones, can reduce side reactions and impurity accumulation caused by feed imbalance, thereby reducing the risk of melamine formation at the source. In particular, when the molar ratio of urea to alkaline earth metal oxides is 2.10:1.00, the obtained dicyandiamide has a purity of 99.88%, a melamine content of <0.01%, and a heavy metal content of 2g / 100g, all meeting pharmaceutical-grade quality requirements.

The invention discloses a negative electrode material with a zinc cyanamide / zinc sulfide heterostructure for a sodium ion battery, a preparation method and application of the negative electrode material and the sodium ion battery, and relates to the technical field of sodium batteries. The negative electrode material provided by the invention is a spherical particle with zinc cyanamide as an inner core and zinc sulfide as an outer protective shell, can provide a reversible specific capacity of 300-900 mAh / g, and can realize rate discharge under a high current density of 10 A / g and a cycle life of 300-3000 times. The invention also provides a preparation method of the negative electrode material, cyanamide salt and zinc salt are mainly used as reaction raw materials, the negative electrode material is obtained by combining a precipitation method with a low-temperature reaction, the method abandons the use of hazardous chemical reagents, the experiment process is carried out under normal pressure, and the cost is low. And the prepared sodium ion negative electrode material has the advantages of controllable core-shell structure, stable electrochemical performance and the like, and can be used in the field of electrochemical sodium ion energy storage.

The application discloses a kind of negative electrode materials with cyanamide zinc / zinc sulfide heterostructure for sodium ion battery and its preparation method and application, sodium ion battery, it is related to sodium battery technical field.The negative electrode material of the present application is with cyanamide zinc as core, zinc sulfide as outer protective shell spherical particle, the negative electrode material can provide 300~900 mAh / g reversible specific capacity, can be realized at 10 A / g high current density rate discharge and 300~3000 cycle life.The application also provides the preparation method of the negative electrode material, mainly cyanamide salt and zinc salt are used as reaction raw materials, obtained by using precipitation method in combination with low temperature reaction, this method discards the use of dangerous chemical reagent, experiment is carried out under normal pressure, and the sodium ion negative electrode material prepared has the advantages, such as controllable core-shell structure, stable electrochemical performance, can be used in electrochemical sodium ion energy storage field.

The utility model belongs to the technical field of cyanamide production, and particularly relates to a device for preparing mono-dicyandiamide through thermal cracking. The device comprises a heater (1), a catalyst tank (2), a melamine tank (3), a downer reactor (4) and a gas-solid separator (5), a heat source inlet (1-1) and a heat source outlet (1-2) are respectively arranged on the heater (1), and a nitrogen inlet (1-3) is arranged close to the heat source outlet (1-2). A catalyst tank (2) is arranged between the nitrogen inlet (1-3) and the heat source outlet (1-2); the heater (1) is connected with the downer reactor (4), and the melamine charging bucket (3) and the like are arranged between the heater (1) and the downer reactor (4). According to the utility model, melamine is taken as a raw material and passes through the downer reactor, rapid cracking is realized at high temperature, back mixing is reduced, the product purity is improved, re-purification and purification of the product are not needed, the working procedure is shortened, and the production efficiency is improved.