154 results about "Metal precipitation" patented technology

A two-step chemical precipitation process involving hydroxide precipitation and sulfide precipitation combined with “field separation ” technology such as magnetic separation, dissolved air flotation, vortex separation, or expanded plastics flotation, effectively removes chelated and non-chelated heavy metal precipitates and other fine particles from water. In the first-step, the non-chelated heavy metals are precipitated as hydroxides and removed from the water by a conventional liquid/solids separator such as an inclined plate clarifier to remove a large percentage of the dissolved heavy metals. The cleaned water is then treated in a second precipitation step to remove the residual heavy metals to meet discharge limits. In the second precipitation step, any metal precipitant more effective than hydroxide for metal precipitation can be used. The invention improves metal removal, lowers cost because fewer chemicals are used, produces less sludge, and reduces the discharge of toxic metals and metal precipitants to the environment. Magnetic separation is preferred for the separation of particles precipitated in the second stage. Similar methods can be employed for separation of other particulates from water. Particulates can also be removed by causing them to adhere to particles of expanded plastic, forming a floc lighter than water, so that the floc can be removed by flotation.

A two-step chemical precipitation process involving hydroxide precipitation and sulfide precipitation combined with “field separation” technology such as magnetic separation, dissolved air flotation, vortex separation or expanded plastics flotation, effectively removes chelated and non-chelated heavy metal precipitates and other fine particles from water. In the first-step, the non-chelated heavy metals are precipitated as hydroxides and removed from the water by a conventional liquid/solids separator such as an inclined plate clarifier to remove a large percentage of the dissolved heavy metals. The cleaned water is then treated in a second precipitation step to remove the residual heavy metals to meet discharge limits. In the second precipitation step, any metal precipitant more effective than hydroxide for metal precipitation can be used. The invention improves metal removal, lowers cost because fewer chemicals are used, produces less sludge, and reduces the discharge of toxic metals and metal precipitants to the environment.

A method of making metal nanostructures having a nanometer size in at least one dimension includes preparing an aqueous solution comprising a cation of a first metal and an anion, and mixing commercial elemental powder particles of an elemental second metal having a greater reduction potential than the first metal with the aqueous solution in an amount that reacts and dissolves all of the second metal and precipitates the first metal as metal nanostructures. The temperature and concentration of the aqueous solution and the selection of the anions and the second metal are chosen to produce metal nanostructures of a desired shape, for example ribbons, wires, flowers, rods, spheres, hollow spheres, scrolls, tubes, sheets, hexagonal sheets, rice, cones, dendrites, or particles.

A device for separating metal components from a colloidal suspension or solution uses a vessel for holding the colloidal suspension or solution. A membrane impermeable to the selected metal components of a colloidal suspension or solution is sealed over a support to form a leaf element. The leaf element includes an outlet for the selected components of the colloidal suspension or solution and is extended into the colloidal suspension or solution. The leaf element is controllably vibrated simultaneously with application of a negative or positive pressure which is used to motivate permeation of the membrane by the liquid of the colloidal suspension or solution to purify it. Metals removed by the method include metals with an atomic number greater than 10 including and/or silicon. The colloidal suspension or solution may optionally contain a metal precipitator such as a dithiocarbamate and/or trithiocarbamate to aid in the separation.

The invention relates to a method for cleaning semiconductor surfaces to achieve to removal of all kinds of contamination (particulate, metallic and organic) in one cleaning step. The method employs a cleaning solution for treating semiconductor surfaces which is stable and provokes less or no metal precipitation on the semiconductor surface.

The electrolysis recovery method for Cu and Ni(NO3)3 from electroplating sewage comprises: adding NaOH into the sewage with at least H2SO4 or HCl to adjust pH till technical request and deposit metal; mixing the sewage contained metal and HNO3; with proper pH value, electrolyzing and controlling current to separate Cu; adding Ni(OH)3 into the liquid without Cu; with proper pH value, heating to deposit; filtering the precipitate, and obtaining the Ni(NO3)3 solution; heating and condensing to obtain the Ni(NO3)3 crystal. This invention is simple and low cost.

The invention provides a metal catalyst preparation method which comprises the following steps: I, providing a metal salt solution, wherein a raising agent, carrier metal and active metal ions with a carbon nanotube preparation activation function are dissolved in the metal salt solution; the raising agent comprises one or more of organic acid, organic alcohol, organic aldehydes, nitrogenous organic compounds and sugar; II, adding a precipitator into the metal salt solution, and stirring so as to obtain composite metal precipitation; III, heating and calcining the composite metal precipitation, and cooling after calcining, and screening, thereby obtaining a metal catalyst. Meanwhile, the invention further discloses a carbon nanotube prepared from the metal catalyst. Problems that the metal catalyst finished product rate of a nanotube catalyst preparation method is low, the particle size is not accordant, and the quality of carbon nanotubes can be affected are solved.

The impurity content of cobaltous sulfate solution obtained after preliminary purification is high, and the conventional method is to sediment metals of cobalt and the like by using sodium salt. Because the alkalinity of the sodium salt is high and partial over-alkali occurs easily, a large proportion of impurities in the solution also form sediments and the cobalt content in finished cobalt hydroxide products is reduced. The invention provides a technology for preparing cobalt hydroxide from cobaltous sulfate solution, which is characterized by the following steps of carrying out first cobalt sedimentation on cobaltous sulfate solution by using cobalt hydroxide in a first cobalt sedimentation channel; processing the first cobalt sedimentation slurry obtained after the reaction by using a cobalt sedimentation buffer channel, then returning 30 to 50% of the obtained slurry to the first cobalt sedimentation channel, and carrying out filter pressing on the rest slurry; drying filter cakes obtained by filter pressing to obtain the dried cobalt hydroxide which is the finished products; and finally carrying out second cobalt sedimentation on the filtrate by using magnesium hydroxide. in the invention, the partial over-alkali is avoided and the cobalt content of cobalt sediments is increased because the magnesium hydroxide slurry of weak alkalinity is used as a precipitant.

The invention provides a preparation method and application of a CuNi-based catalyst. The preparation method comprises the following steps: uniformly mixing urea or concentrated ammonia or a mixture of urea and concentrated ammonia with a copper salt, a nickel salt and a carrier or auxiliary agent in a reflux device under stirring; carrying out ammonia distillation to obtain a metal precipitate; and then successively carrying out centrifugation, washing, drying, calcination and reduction so as to obtain the CuNi-based catalyst. The CuNi-based catalyst comprises, by mass, 30-50% of CuO, 5-25% of NiO and 30-60% of a carrier or auxiliary agent. The CuNi-based catalyst prepared in the invention is free of active component loss and stable in catalytic performance; when the CuNi-based catalyst is applied to CO2 hydrogenation and HN(CH3)2(DMA) reaction for synthesis of DMF, the yield of DMF is high, and required raw materials are cheap and easily available; and the preparation method is simple in process, easy to operate, low in process cost and high in repetitive rate, and thus has good application prospects.

Processes for the treatment of solutions used for the decontamination of radioactively contaminated surfaces wherein the solution contains radioactive metal ions and organic complexing agents are described herein. The processes include treating the solutions with a reagent suitable for the destruction of the complexing agent and contains a metal capable of existing in more than one oxidation state, and raising the pH of the resultant solution to a level at which the metal of the reagent precipitates or flocs out of the solution. Processes in which the contaminated solutions are treated with electromagnetic radiation, treated with UV or visible radiation, and treated at an ambient temperature are also described herein.

The invention provides an automatic dosing control method for removing heavy metal ions in wasterwater containing the heavy metal ions and a device thereof. The method and the device are mainly suitable for automatic dosing control during treating the wastewater containing the heavy metal ions by adopting the chemical precipitation method. The control method comprises the following steps of: 1. detecting an ORP1 value with a certain pH value before heavy metal precipitator is added; 2. detecting an ORP2 value after the heavy metal precipitator is added and a heavy metal complete precipitation reaction is generated; 3. automatically controlling the dosage and the dosing process of the heavy metal precipitator according to an ORP difference value (ORP1 minus ORP2) between the ORP1 which is detected before the heavy metal ion precipitation is completed and the ORP2 which is detected after the heavy metal ion precipitation is completed. The control device comprises two sets of online detecting ORP meters, an automatic control system adopting the PID technology and the PLC technology and a plurality of dosing pumps. The invention is an automatic continuous dosing control technology for the heavy metal ion precipitation reaction in the treatment for the wastewater containing the heavy metal ions through combining the ORP technology and the PID/PLC technology into a whole, can effectively solve the continuous precise dosing problem during the treatment of the wastewater containing the heavy metal ions, and ensure that the treated water which can meet the standard is discharged continuously and stably.

A method of forming a hydrogen transport membrane to separate hydrogen from a hydrogen containing feed in which a porous ceramic support is formed to support a dense layer of palladium or an alloy of palladium serving as a hydrogen transport material. Isolated deposits of palladium, a palladium alloy or a component of such alloy are produced on a surface of the porous ceramic support that bridge pores within the porous ceramic support without penetrating the pores and without bridging regions of the surface defined between the pores. The isolated deposits of the metal are produced by an electroless plating process that involves contacting the porous ceramic support with a precipitating agent so that the precipitating agent fills the pores but does not seep out of the pores onto the regions of the surfaces defined between the pores. The surface is then contacted with a salt solution containing a salt of the metal so that said metal precipitates and produces the isolated deposits of the metal. Thereafter, the dense layer is formed on the surface having the isolated deposits.

The invention discloses a heavy metal precipitant, a preparation method thereof and a heavy metal wastewater treatment method. The preparation method of the heavy metal precipitant comprises the steps that modifiers are added into Fe2+ water solution to regulate the pH value between 10.0 and 13.0; the mixture is stirred and subjected to reaction until calomel electrodes are adopted as reference electrodes to measure the first oxidation-reduction potential between minus 500mv and minus 700mv; sediment produced in reaction is acquired, and then the heavy metal precipitant is obtained, wherein the modifiers include one or more of NaOH, KOH and Ca(OH)2. According to the preparation method of the heavy metal precipitant, only relatively cheap ferrous salt is adopted as an iron source needed for preparing the heavy metal precipitant, so that the preparation cost of the heavy metal precipitant is greatly lowered; moreover, the oxidation-reduction potential and the pH value are used as control parameters in the preparation process, so control is easy and convenient, and stable quality of the heavy metal precipitant can be guaranteed.

A method of etching and a method of regenerating a spent etching solution comprising adding metal particles to a spent etching solution to precipitate the residue metal or metals in the spent etching solution in the form of metal powders, removing the metal powders from the spent etching solution and recovering the metals in the metal powders for future use. The remaining portion of the spent etching solution can then be regenerated to produce a fresh batch of etching solution.

The invention provides a comprehensive recovery device and method for valuable metal in copper smelting acidic wastewater. The device comprises an acidic wastewater pump, a first filter press, a reaction tank, a reaction liquid pump and a second filter press which are sequentially connected, wherein the top of the reaction tank is connected with the first filter press and the bottom of the reaction tank is connected with the reaction liquid pump; the reaction tank is internally provided with a steam heating coil and a stirring, and the top of the reaction tank is further connected with a reagent tank through a metering pump. The method mainly comprises the following steps: (1) carrying out press-filtering in the first press filter to remove solid particles in acidic wastewater; (2) adding a sodium thiosulfate solution in the reagent tank by the metering pump into the reaction tank and controlling the heating temperature of the reaction tank at 60-70 DEG C; and (3) feeding the solution after reaction into the second press filter to be press-filtered and discharging the filtrate after neutralizing treatment. According to the device and method, the recovery rate of metal precipitates such as copper, rhenium, silver and bismuth in the acidic wastewater reaches up to over 90%, so that the loss of valuable metals in the acidic wastewater is effectively solved.

A method of flotation processing ores and other mineral materials containing soluble nonferrous base metal and sulfide minerals involves dissolving the soluble nonferrous base metal and precipitating the soluble nonferrous base metal in the form of a floatable precipitate that is collected as part of a sulfide concentrate. The use of an oxygen-deficient flotation gas, such as nitrogen gas, promotes the precipitation of the floatable precipitate. A method for removing dissolved nonferrous base metal from solution involves contacting the solution with a particulate containing sulfide minerals under conditions promoting precipitation of the nonferrous base metal onto the sulfide mineral.

A disclosed method for recovering a cobalt manganese catalyst from a terephthalic acid reaction mother solution comprises the following steps: recovering acetic acid form the reaction mother solution by evaporation; adding water to concentrated mother solution, and cooling to precipitate organic compound precipitation from the reaction mother solution; separating and recovering the organic compound precipitation; heating the solution and adding alkali and an oxidant, so as to enable metal ions such as iron, chromium and the like in the solution to form acid-corroding metal precipitation and precipitate; removing the acid-corroding metal precipitation, and continuing to add alkali into the solution, so as to enable metal ions such as cobalt, manganese and the like to precipitate and form a cobalt manganese catalyst precipitation; and performing filtering and water washing on the cobalt manganese catalyst precipitation, adding into hydrobromic acid or acetic acid, so as to dissolve the cobalt manganese catalyst precipitation and recover the precipitation as the cobalt manganese catalyst. Therefore, the purpose of recovering the cobalt manganese catalyst efficiently for reutilization is realized.

The invention discloses a method for preparing battery-grade anhydrous iron phosphate from industrial ammonium phosphate clear liquid or industrial ammonium phosphate mother liquor. The method comprises the following steps: S1, fluorine removal: adding diatomite and sodium carbonate into the industrial ammonium phosphate clear liquid or the industrial ammonium phosphate mother liquor to remove fluorine; S2, refining: adjusting the pH value of the phosphorus-containing solution in the step S1, and removing impurities such as calcium, magnesium, manganese, aluminum and the like; S3, heavy metal removal: adding a heavy metal precipitant into the phosphorus-containing solution with low impurity ion content in the step S2 to remove heavy metal impurities; S4, synthesis of iron phosphate dihydrate: fully reacting the refined phosphate solution obtained in the step S3 with ferrous sulfate under the action of an oxidizing agent to prepare the iron phosphate dihydrate; and S5, preparation of battery-grade anhydrous iron phosphate: calcining the iron phosphate dihydrate prepared in the step S4 to prepare the battery-grade anhydrous iron phosphate. The method provided by the invention is simple in technological process and low in overall cost, and has relatively high industrial application value and economic value.

The invention provides a method for recovering valuable metals from copper slag. The recovery method comprises the steps that under the microwave condition, the copper slag, a chlorinating agent and awave absorbing material are roasted, roasted slag and roasted flue gas are obtained, in the roasting process, the microwave frequency is 2450 MHz, and the microwave power is 2-75 KW; and the roastedflue gas, a flue gas absorbent and a metal ion precipitator are subjected to a precipitation reaction, metal precipitates are obtained, and the flue gas absorbent is water or an alkaline aqueous solution. By the adoption of the method, the iron element and other valuable metal elements in the copper slag can be effectively separated, then targeted treatment can be carried out, and the effect of greatly increasing the recovery rate of valuable metals in the copper slag is achieved; and in addition, the recovery method has the advantages of being wide in adaptability to the copper smelting slag,simple in technological process, high in recovery rate of valuable metal and the like.

The invention discloses a regeneration method for stainless steel mixed acid pickling waste acid. The regeneration method comprises the following steps that an oxidizing agent is added into stainlesssteel mixed acid pickling waste acid to adjust redox potentials of the waste acid system, and the stainless steel mixed acid pickling waste acid contains nitric acid and hydrofluoric acid; then the obtained mixed solution is made to react under the heating condition and the pressing condition; and solid-liquid separation is conducted on slurry formed after the reaction to obtain a regenerated acidsolution. According to the method, metal ions in the waste acid are removed through high-temperature hydrolysis, the regenerated acid solution is directly returned into stainless steel washing procedures, a metal precipitate is a non-toxic and harmless stable oxide, so that a zero-emission clean treatment process is realized.