213 results about "Sodium cyanide" patented technology

The invention provides a gold leaching agent for treating high-carbon gold-bearing minerals and a gold leaching process, and belongs to the technical field of hydrometallurgy. According to the gold leaching agent, guanidinium thiocyanate is used as an agent main body, a hydroximic acid compound is used as a complexing synergist, and soluble inorganic salt of ferric iron is used as a competitive adsorbent. In a leaching system, guanidine thiocyanate can be decomposed to generate guanidine, sodium sulfide, sodium thiocyanate and water. Thiourea anions are converted into cyanamide under the alkaline condition, then cyanamide is slowly released and decomposed into cyanide ions, the cyanide ions are complexed with gold ions, and gold leaching is achieved. Namely, guanidinium thiocyanate has the effect of releasing the cyanide ions step by step, and slow release of the cyanide ions is realized. The gold leaching agent system does not contain cyanide (sodium cyanide, potassium cyanide and the like) and is a clean and environment-friendly agent system, and efficient leaching of gold in high-carbon gold-bearing minerals can be achieved through the synergistic effect of all functional agent components.

The invention discloses an ammonia nitrogen detection system and an application method thereof, and ammonia nitrogen detection test paper, the ammonia nitrogen detection system is prepared by the following steps: step SA1) preparing a dipping mixed solution, the dipping mixed solution comprises: a potassium sodium tartrate solution with a concentration of 3-60 g / L; a sodium salicylate solution with a concentration of 20-320 g / L; the concentration of the sodium nitroprusside solution is 0.1 to 0.8 g / L; and deionized water. On the basis of the principle of salicylic acid-pypocholoride spectrophotometry, the impregnated test paper, the reagent tube and the standard colorimetric card are combined, and the rapid ammonia nitrogen detection system special for medium-concentration sewage detection is successfully developed. The toxicity problem of mercury iodide in a Nessler reagent method and the toxicity problem of phenol in a phenol-pypocholoride spectrophotometric method are avoided, main reagents are non-toxic and harmless to a human body, interference of metal ions in a water sample can be effectively eliminated by adopting sodium potassium tartrate tetrahydrate as a chelating agent, and the detection stability and accuracy are improved.

The invention discloses a high-impact material prepared from recycled polypropylene and a preparation method of the high-impact material, and relates to the field of materials. When recycled polypropylene is used for preparing the high-impact material, firstly, polypropylene is grafted with vinyl diphenylphosphine, then the grafted polypropylene is reacted with 1-(3-chlorphenyl)-2-propyn-1-ol, and then the reacted polypropylene is reacted with 6-(methyl formate) pyridine-3-boric acid to obtain modified polypropylene; secondly, the calcium carbonate pretreated by 3-aminopropyltrimethoxysilane reacts with 3-thiophenecarboxaldehyde, thiophene, 6-(thiophene-2-yl) pyridine-2-carboxylic acid and 6-(3-thienyl) pyridine-2-formaldehyde are polymerized on the surface of the calcium carbonate, and modified calcium carbonate is obtained; and finally, carrying out melt blending on recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide, and carrying out extrusion granulation to obtain the high-impact material. The high-impact material prepared by the invention has good impact resistance, aging resistance and antibacterial property.

The invention relates to the technical field of packing scale equipment, and provides a special packing scale for powdery sodium cyanide and a control method thereof.The special packing scale comprises a feeding hopper and a vibration table which are distributed up and down, a connecting flange coaxially fixed to a discharging opening of the feeding hopper, and a receiving hopper which is coaxially connected to the connecting flange in a sleeving mode, and the outer wall of the receiving hopper is annularly provided with a driving gear and is driven by a motor on the feeding hopper; at least one concave cavity is formed in the side wall of the receiving hopper, a rod body is hinged in the concave cavity, a replaceable balancing weight is arranged at the free end of the rod body, when the receiving hopper rotates, the rod body is unfolded under the action of centrifugal force and knocks a ton bag sling, meanwhile, the vibration table acts on the bottom of a ton bag, and the vibration table and the receiving hopper cooperatively excite the standing wave effect of the ton bag. The rod body periodically knocks the sling under the action of centrifugal force, and the frequency can be adjusted through the balancing weight. When the knocking frequency is close to the inherent frequency of the ton bag, vibration of the hanging belt can be transmitted to the whole bag body, the resonance phenomenon is caused, the vibration table at the bottom is matched to excite the standing wave effect, and loosening and even distribution of materials are achieved.

The invention relates to an efficient copper removal and recycling process for copper-cyanogen complex wastewater, which comprises the following steps: (1) critical acidification-selective crystallization of the copper-cyanogen complex wastewater: directionally recombining a copper-cyanogen complex to generate insoluble CuCN crystals by accurately regulating and controlling the pH value of the wastewater; (2) rotational flow enhanced crystallization: separating CuCN crystals from overflow liquid through a hydrocyclone; (3) gradient activation of a composite vulcanizing agent for deep copper removal: enabling the fine CuCN particles and the dissolved-state low-coordination copper-cyanogen complex to react to generate insoluble CuS crystals by adjusting the pH value and adding the composite vulcanizing agent; and (4) magnetic seed enhanced separation: carrying out magnetic separation by adopting modified magnetic seeds and a low-intensity magnetic separator, separating CuS magnetic flocs from the wastewater, and finally obtaining purified tail liquid. According to the closed-loop process, copper in the copper-cyanogen complex wastewater can be efficiently removed and recovered, the purified tail liquid can be reused for cyanidation leaching operation, the unit consumption of sodium cyanide is remarkably reduced, the leaching rate of gold and silver is increased, and zero discharge of wastewater and full recovery of copper resources are truly achieved.

The invention provides a sulphide ore alkaline desulfurization and cyanidation gold leaching agent system and a method for extracting gold through the sulphide ore alkaline desulfurization and cyanidation gold leaching agent system, and belongs to the technical field of hydrometallurgy. According to the method, a ternary agent system consisting of potassium ferricyanide, low-concentration sodium cyanide and thioguanosine is constructed. An efficient'oxidation-inhibition 'synergistic system is formed between the auxiliary desulfurization agent potassium ferricyanide and the thioguanosine. The rapid and selective oxidation of potassium ferricyanide is smoothly carried out under the synergistic effect of thioguanosine, minerals are thoroughly decomposed, and the surface keeps high activity; meanwhile, due to the existence of the thioguanosine, the local microcell passivation risk and catalytic electron transfer can be eliminated more directionally. The sodium cyanide and the sodium cyanide complement each other, it is jointly guaranteed that the exposed gold can be smoothly and efficiently leached through follow-up low-concentration sodium cyanide, finally, the total consumption of reagents is reduced, environmental pollution is reduced, and meanwhile high-recovery-rate extraction of the gold in the sulfide ore difficult to treat is achieved.

A method and system for converting copper cyanide to copper oxide is provided. The method includes contacting a copper cyanide solution with an acidic solution in a precipitation tank under reaction conditions sufficient to produce a copper cyanide slurry, removing the copper cyanide slurry from the precipitation tank, separating solid copper cyanide from the copper cyanide slurry in a first separation device, removing the solid copper cyanide from the first separation device, contacting the solid copper cyanide with a sodium hydroxide solution in a production tank under reaction conditions sufficient to produce a copper oxide slurry, removing the copper oxide slurry from the production tank, separating solid copper oxide from the copper oxide slurry in a second separation device, and removing from the second separation device any residual sodium hydroxide not reacted during the process of contacting the solid copper cyanide with the sodium hydroxide solution in the production tank.

The invention provides a gold leaching agent of a compound leaching aid system and a dump leaching process, and belongs to the field of hydrometallurgy, the gold leaching agent comprises an agent main body and the leaching aid system, the agent main body is sodium cyanide, the leaching aid system comprises an oxidizing agent, an oxidation synergist and a chelating gain agent, the chelating gain agent is a furan ring-shaped hydroxamic acid compound. According to the method, the high-selectivity leaching auxiliary is designed, the components of the dump leaching agent system are regulated and controlled, and efficient gold extraction of the dump leaching process is achieved through the synergistic effect of all the components in the system. Wherein the chelating gaining agent can form a stable chelate with metal ions in a solution through a special annular structure and chelating capacity, so that the metal ions are prevented from precipitating again, gold ions in the solution are kept in a free state, further reaction of sodium cyanide is facilitated, and the leaching rate of gold is increased. Meanwhile, the aromaticity of furan rings and oxygen heteroatoms enhance the solubility and stability of the furan rings in water, and the effect of the whole leaching process is improved.

The invention relates to the field of metallurgy and chemical engineering, in particular to a heap leaching gold extraction method for low-grade gold sulfide ore. Comprising the following steps that an anti-seepage bottom mat is laid on a dump leaching site; pre-treating the sulfide gold ore by using quick lime; ore crushing; ore is poured and piled on the upper portion of the bottom pad; spraying is conducted on the top of the ore heap and a side slope frame pipe, the gold-containing pregnant solution is collected, and the spraying solution is a sodium cyanide solution; and recovering gold from the gold-containing pregnant solution. According to the heap leaching gold extraction method provided by the invention, the quicklime is adopted to carry out pretreatment (iron removal, desulfurization and arsenic removal) on the sulfide gold ore, and then processes of subsequent ore crushing, heap building, spraying, adsorption and the like are carried out, so that the difficult problems of heap leaching utilization and popularization of low-grade sulfide ore resources are solved.

The invention discloses a preparation method of (S)-3-aminobutyronitrile hydrochloride compounds, which comprises the following steps: S1, chlorination reaction: adding thionyl chloride and a catalyst into a reaction solvent, controlling a certain temperature, dropwise adding a compound 1, reacting at a certain temperature after dropwise adding, and dropwise adding into water for quenching to obtain an aqueous solution of a compound 2; s2, cyaniding reaction: adding the compound 2 into a reaction solvent, adding a 30% sodium cyanide solution, controlling a certain temperature, reacting for a certain time, extracting and layering after the reaction is finished, washing an organic phase with a sodium chloride solution, and concentrating to obtain a compound 5; and S3, salt forming reaction: dropwise adding a solution of an HCl (gas) organic solvent into the organic solvent of the compound 5, controlling a certain temperature, reacting for a certain time, and after the reaction is finished, cooling, filtering and drying to obtain a target compound 6. The (S)-3-aminobutyronitrile hydrochloride is obtained with the mole yield of 68.5%, the cost is low, and the cost competitiveness is very high.

The present invention relates to a method for producing a composite adsorbent of ferrocyanide of a transition metal in the matrix of silica gel comprising the following steps: (i) preparing a first aqueous composition comprising at least the mixture of a sodium or potassium ferrocyanide with a sodium silicate solution so as to obtain the dissolution of salts; (ii) preparing a second composition comprising the mixture of at least: a transition metal salt chosen from one or more of the following compounds: nickel, copper, zinc, cobalt, and an inorganic acid; (iii) mixing the first aqueous composition with the second composition until a suspension is obtained; (iv) adding an inorganic acid or base so that the suspension obtained at the end of step (iii) has a pH ranging from 4 to 9;(v) demixing the suspension obtained at the end of step (iv) so as to obtain a precipitate within a liquid phase; (vi) separating said precipitate, rinsing and drying the precipitate, so as to obtain a solid precipitate, characterized in that the first aqueous composition comprises a soluble rubidium or cesium salt, and the second composition further comprises a soluble metal salt chosen from one or more of the following compounds: aluminum, titanium, zirconium.;

The invention relates to a method for recovering gold by adopting a leaching process, which is beneficial to full contact of a gold ore raw material with sodium cyanide through a crushing and screening process, and improves the recovery rate of the gold ore. The cyaniding gold-containing barren liquor generated after washing of a carbon extraction sieve in the process of leaching and recovering gold from the high-grade raw ore is used for replacing direct spraying of sodium cyanide on the secondary-grade raw ore, so that the consumption of the sodium cyanide is reduced, and the economic cost of recovering gold is reduced; meanwhile, the problem that the smelting cost of gold mud produced by leaching of the high-grade raw ore is increased due to the fact that cyanided gold-containing barren liquor which is continuously accumulated and enriched with impurity ions is directly recycled and used for leaching of the high-grade raw ore is avoided, and electrolysis barren liquor generated after electrolysis of the gold-containing barren liquor is treated through an intermediate product treatment process; according to the method, impurity ions enriched in the electrolytic barren liquor are removed, meanwhile, in the electrolytic barren liquor treatment process, tail gas and tail liquor generated in the high-grade raw ore leaching gold recovery process are neutralized, and the influence of the tail gas on the environment is reduced.

This invention discloses a method for recycling and reusing cyanide silver plating wastewater. The method includes four steps: separation of silver ions and cyanide, concentration of the silver-containing solution, cyanide concentration, electrolysis and residual liquid recycling, and reuse of reclaimed water. This method achieves the separate recycling and reuse of silver, cyanide, and water. The silver-containing solution is electrolyzed to obtain metallic silver, the cyanide concentrate's main component is sodium cyanide or potassium cyanide solution, and the reclaimed water with a conductivity below 20 μS / cm is reused in the production line. This method not only maximizes resource utilization and reduces wastewater discharge, but also separates most of the cyanide from the silver-containing solution during electrolysis, making the electrolysis process safer. Furthermore, the residual liquid after electrolysis can be recycled multiple times for the separation and concentration of silver ions and cyanide.

The utility model discloses a high-concentration sodium cyanide wastewater treatment system, which is characterized in that the whole system is in an under-pressure closed state, no waste gas is generated in the process, the safety can be ensured, cyanogen breaking is carried out through alkaline hydrolysis and hydrogen peroxide oxidation in the reaction process, the cyanogen breaking effect is obvious, the concentration of sodium cyanide in wastewater can be reduced from 20000 mg / L to 0.5 mg / L, and the concentration of sodium cyanide in wastewater can be reduced from 20000 mg / L to 0.5 mg / L. And through two-stage under-pressure heat exchange and one-stage normal-temperature heat exchange in the heat recovery device, waste heat energy is utilized to the maximum extent, and the energy-saving effect is obvious.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a Prussian blue sodium battery positive electrode material and a preparation method thereof.The preparation method comprises the steps that anhydrous sodium ferrocyanide, anhydrous manganese sulfate and a NaA molecular sieve are mixed and preliminarily ground, and a precursor mixture is obtained; placing the precursor mixture in a planetary ball mill for ball milling to obtain a primary reaction product; and washing the preliminary reaction product, and carrying out vacuum drying to obtain the Prussian blue sodium battery positive electrode material. The method is low in material loss and short in generation period, and the prepared Prussian blue sodium battery positive electrode material is low in crystal water content and has good cycle stability.

The invention relates to an environment-friendly gold leaching agent and a gold leaching method, and belongs to the technical field of gold leaching. The environment-friendly gold leaching agent comprises sodium cyanurate and guanidine salt. The gold leaching agent provided by the invention has a good gold leaching effect, is high in gold selectivity, does not contain traditional highly toxic sodium cyanide, is small in environmental pollution, and is green and environment-friendly.

The invention belongs to the technical field of medicine synthesis, and discloses a preparation method of a sodium nitroprusside raw material medicine. According to the method, weak acid is adopted for catalysis, the effect of remarkably reducing generation of toxic substances such as cyanide and nitrogen dioxide is achieved by controlling the material dripping speed and the dripping pH, the reaction is mild, the technological operation is safe and controllable, and industrial production of the sodium nitroprusside raw material medicine is facilitated. According to the preparation method of some examples, silica gel filtration is used for post-treatment, the residual risk of impurities such as sodium ferricyanide, ferric ferrocyanide and ferric ferricyanide is reduced, and the purity of the raw material medicine is larger than or equal to 99.9% and is far superior to the requirements of pharmacopoeia of various countries.

The invention discloses a lanthanide-doped Prussian blue positive electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing and dissolving sodium ferrocyanide and lanthanide metal salt to obtain a mixed solution; and under a protective atmosphere, dropwise adding the mixed solution into a mixed chelating agent salt solution through a peristaltic pump, and reacting to obtain the lanthanide-doped Prussian blue positive electrode material. The lanthanide metal in the lanthanide-doped Prussian blue positive electrode material occupies the Na site, the single iron source coprecipitation method is adopted for synthesis, the process concentration is uniform, the synthesized positive electrode material has fewer defects, the material structure is stable, the rate capability is excellent, the specific capacity is high, and the application prospect is very good.

The present application relates to a process for producing synthetic ammonia by using hydrogen-containing tail gas, comprising the following steps: S1: sodium cyanide tail gas is pressurized, then heated and water-cooled. S2: the impurity-removed tail gas is desulfurized. S3: the desulfurized tail gas is mixed with chlor-alkali tail gas, the mixed gas is heated and deoxidized. S4: the deoxidized tail gas is pressurized and enters a PSA (pressure swing adsorption) device for pressure swing adsorption treatment, obtaining high-purity hydrogen. In the PSA device, dehydrating, carbon dioxide, methane, carbon monoxide and nitrogen adsorbents are sequentially arranged. The carbon dioxide adsorbent is activated carbon modified by carbonate and strong alkali, and the nitrogen adsorbent is 13X zeolite molecular sieve modified by Na + and Ba 2+ and Ca 2+ ion exchange. S5: nitrogen reacts with the high-purity hydrogen obtained in step S4 to generate ammonia. The present application can improve the adsorption capacity of the adsorbent for impurity gas, thereby reducing the replacement frequency of the adsorbent, prolonging the service period and service life of the adsorbent, and improving the production efficiency.

The invention provides a preparation method and application of a sodium cobalt hexacyanoferrate composite material based on three-dimensional honeycomb MXene. The composite material is prepared through the following steps that 1, a Ti3AlC2 MAX phase reacts with a mixed solution of lithium fluoride (LiF) and concentrated hydrochloric acid (HCl), an Al atomic layer is removed through etching, and layered MXene is obtained; 2, mixing the layered MXene with a polymethyl methacrylate (PMMA) template, centrifuging, washing, drying and calcining to prepare three-dimensional honeycomb MXene; and 3, dispersing the three-dimensional honeycomb MXene in deionized water, sequentially adding a cobalt source and a sodium ferrocyanide (Na4Fe (CN) 6) solution, and carrying out an in-situ coprecipitation reaction to obtain the composite material. In the composite material, the sodium cobalt hexacyanoferrate is of a cubic structure and is uniformly embedded into a three-dimensional honeycomb MXene framework. The composite material disclosed by the invention is applied to a water-based sodium-ion battery positive electrode material, and has high conductivity, excellent rate capability and cycling stability.

The invention discloses a kind of recycling polypropylene to prepare high-impact material and preparation method thereof, relate to the field of materials. When the present invention uses recycling polypropylene to prepare high-impact material, first, polypropylene is grafted with vinyl diphenylphosphine, then reacted with 1-(3-chlorophenyl)-2-propyn-1-ol, and then reacted with 6-(methyl formate) pyridine-3-boric acid to obtain modified polypropylene; Secondly, calcium carbonate pretreated with 3-aminopropyltrimethoxysilane and 3-thiophene carboxaldehyde are reacted, and thiophene, 6-(thiophene-2-yl) pyridine-2-carboxylic acid, and 6-(3-thienyl) pyridine-2-carboxaldehyde are polymerized on the surface of calcium carbonate to obtain modified calcium carbonate; Finally, recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide, and bismaleimide are melt-blended, and then extrusion granulation is performed to obtain high-impact material; The high-impact material prepared by the present invention has good impact resistance, anti-aging performance and antibacterial performance.

The invention provides a method for synthesizing ethyl 4-cyano-3-hydroxybutyrate by a pure hydrocyanic acid method, which is characterized in that ethyl 4-chloro-3-hydroxybutyrate and hydrocyanic acid are used as raw materials, a biological enzyme is used as a catalyst, the pH value of a reaction solution is controlled to be 6.5-7.5, and the ethyl 4-cyano-3-hydroxybutyrate is synthesized; the hydrogen cyanide is used as a raw material, so that the cost of a sodium cyanide preparation process can be reduced, the consumption of sodium hydroxide can be reduced, and the treatment cost of pollutants (sodium salt) can be reduced. The method has the advantages of being high in reasonability, low in material loss and high in production efficiency. The ethyl 4-cyano-3-hydroxybutyrate prepared by the method has the yield of 80%, the content of more than or equal to 98.5% and the single impurity content of less than 0.5%.

The application discloses a preparation method of ammonium glufosinate, which comprises the following steps: adding diethyl malonate and liquid bromine into a first solvent to react to obtain intermediate I; adding the intermediate I, potassium phthalimide and a quaternary ammonium salt catalyst into toluene to react to obtain intermediate II; adding the intermediate II, potassium carbonate, 1,2-dibromoethane and a phase transfer catalyst into a second solvent to react to obtain intermediate III; adding the intermediate III and diethyl methyl phosphonite into toluene to react under argon to obtain intermediate IV; adding the intermediate IV into hydrochloric acid to react under reflux; cooling, precipitation, drying to obtain intermediate V; mixing the intermediate V with water, passing in ammonia and adjusting pH value; adding methanol and stirring to react; cooling, filtering and drying to obtain ammonium glufosinate. The method can avoid using sodium cyanide or hydrocyanic acid, and no large amount of difficult-to-separate ammonium chloride is generated, the content of the obtained ammonium glufosinate is 90% to 98%, and the total yield is greater than 68%.

The present invention discloses a Prussian blue-based sodium-ion battery positive electrode material, a preparation method, and applications thereof. The method comprises: mixing sodium ferrocyanide, oxalate, and a non-aqueous solvent, subjecting the mixture to a ball-milling reaction, and washing the product after the ball-milling reaction to remove unreacted raw materials and a portion of sodium oxalate generated by the reaction, thereby obtaining the Prussian blue-based sodium-ion battery positive electrode material. The present invention can synthesize Prussian blue-based compounds with low defects and low interstitial water molecule content, thereby improving the sodium storage performance and capacity utilization of such materials; it also reduces the probability of side reactions in the electrolyte causing cell bloating. In addition, the use of oxalate-based raw materials can also generate a sodium oxalate-based positive electrode sodium supplement during the synthesis of the Prussian blue-based compound, thereby replenishing sodium ion loss caused by SEI film formation or other side reactions during the initial charge.

The present invention relates to the technical field of organic chemistry, and discloses a preparation method of 9-phenanthrene formic acid, wherein the preparation method comprises the following steps: using phenanthrene as a main raw material, iron bromide or zinc bromide as a catalyst, reacting with hydrobromic acid and hydrogen peroxide at 20 to 50 ° C to generate 9-bromophenanthrene, 9-bromophenanthrene reacts with cyanide under a catalyst to generate 9-nitrile phenanthrene, and then hydrolyzing under alkaline conditions to obtain 9-phenanthrene formic acid. The present invention uses cheap and readily available raw materials such as phenanthrene, hydrobromic acid, hydrogen peroxide and sodium cyanide to prepare 9-phenanthrene formic acid, with low production cost, high conversion rate, good product quality, mild reaction conditions, low equipment requirements, and can be used for large-scale industrial preparation of 9-phenanthrene formic acid.

The application provides a synthesis method of 4-(hydroxymethyl phosphine) 2-carbonyl butyric acid, comprising the following steps: a) mixing acryloyl chloride, a first solvent, a polymerization inhibitor, a catalyst and sodium cyanide, performing a substitution reaction, and obtaining an acryloyl cyanide intermediate after reduced pressure distillation; b) mixing the acryloyl cyanide intermediate obtained in the step a) with hydrochloric acid and a polymerization inhibitor, performing a hydrolysis reaction, and obtaining 2-carbonyl-3-butenoic acid crude product after purification treatment; c) mixing the 2-carbonyl-3-butenoic acid crude product obtained in the step b) with a second solvent and methyl phosphinite, performing an addition reaction, recovering the solvent after water separation and extraction, and obtaining a ketonic acid ester solution; and d) adding hydrochloric acid to the ketonic acid ester solution obtained in the step c) to adjust the pH to be less than or equal to 3, performing a hydrolysis reaction, and obtaining 4-(hydroxymethyl phosphine) 2-carbonyl butyric acid after purification. The synthesis method selects inexpensive acryloyl chloride as a raw material, has mild reaction conditions, is simple to operate, has low production cost, is easy to realize industrialization, and has high yield.

The invention relates to an efficient preparation method and application of optically pure beta-cyanone. The invention belongs to the technical field of fine chemical synthesis. The invention aims to solve the technical problems of low yield, long reaction time, harsh reaction conditions and unsuitability for industrial production of the existing method for preparing optically pure beta-cyanone through asymmetric conjugate cyanidation addition reaction. According to the method, an alpha, beta-unsaturated carbonyl compound is taken as a substrate, acetone cyanohydrin is taken as a cyanogen source, and under the action of a cinchona alkali derivative, alkali and an additive, the optically pure beta-cyanoketone is prepared by heating in a nitrogen atmosphere in one step without tedious operation. By screening cinchona alkaloid derivatives, alkali, additives, reaction temperature and reaction solvents and coordinating and controlling the optimal proportion of all the substances, side reactions are inhibited to the maximum extent, beta-cyanoketone is obtained with high stereoselectivity and yield, and possibility is provided for industrial production of optically pure beta-cyanoketone. The method is mild in condition, simple in operation process, short in reaction time and environmentally friendly, acetone cyanohydrin serves as a cyanogen source, substances such as highly toxic sodium cyanide, TMSCN low in atom utilization rate and high in price are replaced, the application range of a substrate is good, and the method can be widely applied to the fields of biochemistry and medicinal chemistry.

The invention relates to a method for producing alkali metal cyanide briquettes, in particular sodium cyanide briquettes, the method comprising: i) providing an aqueous suspension containing alkali metal cyanide crystals; ii) separating the alkali metal cyanide crystals from the suspension as a moist mass by means of a discontinuously operating centrifuge; iii) temporarily storing the separated moist mass in a buffer container; and iv) feeding the separated moist mass from the buffer container into a continuously operating briquetting machine, in which the moist mass is pressed to form the alkali metal cyanide briquettes. The invention also relates to a device for producing alkali metal cyanide briquettes, in particular sodium cyanide briquettes, in accordance with the method according to the invention.

The application provides a method for detecting the titer of vitamin B12 in a fermentation liquor. The method comprises the following steps: preparing a potassium dichromate solution, a hydrochloric acid solution and a potassium dihydrogen phosphate solution, mixing the three solutions with the vitamin B12 fermentation liquor under certain conditions to generate cyanocobalamin, and then testing the titer of the cyanocobalamin by using a high performance liquid chromatography. The titer of the vitamin B12 detected by using the method is consistent with the titer detected by using a sodium cyanide method. The operation method greatly reduces the safety risk of an analyst caused by using the sodium cyanide, and the operation method is simple, easy to manage in a laboratory and can save the testing cost.

The utility model discloses a filter for sodium cyanide solution production, which relates to the technical field of filters, and comprises a machine body and a cover plate, one side of the machine body is provided with a liquid inlet, one side of the machine body far away from the liquid inlet is provided with a liquid outlet, the machine body is internally provided with a filter cartridge, and the top of the machine body is provided with the cover plate. According to the filter for sodium cyanide solution production, a connecting block is rotated to drive a threaded rod and a cover plate to perform threaded transmission, the threaded rod can drive a conical pressing block to move upwards when moving, the pressing block is gradually separated from a push block when moving, at the moment, a spring is reset, a limiting rod is pushed to rotate, and the limiting rod pushes the push rod to move; when the push rod moves, the push rod is limited by the fixing block, the push rod is prevented from deviating, and when the limiting rod rotates to break away from limiting of the machine body, the movable cover plate is separated from the machine body.