31results about How to "Reduce molybdenum content" patented technology

The invention discloses a high-activity propylene gas-phase epoxidation catalyst, TiO2-MoO3-Bi2SiO5/SiO2, for preparing propylene oxide and a preparation method thereof. The catalyst is used for a propylene gas-phase epoxidation reaction for preparing the propylene oxide, which takes molecular oxygen (O2) or nitric oxide (NO) as an oxidant; reaction conditions are moderate and no inhibitor is needed; the catalyst has high catalytic activity. The catalyst takes a SiO2 mesoporous material Bi2SiO5/SiO2 containing bismuth silicate (Bi2SiO5) as a carrier, MoO3 as an active component and TiO2 as an auxiliary agent. The catalyst comprises following components in percentage by mass: 64.6%-98.8% of the carrier Bi2SiO5/SiO2, 1.1%-22.8% of the MoO3 and 0.1%-12.6% of the TiO2. The mol ratio of Si to Bi in the carrier Bi2SiO5/SiO2 is 30-200. The catalyst is synthesized by using a hydrothermal method; molybdenum and titanium precursors in the active component MoO3 and the auxiliary agent titanic oxide are immersed into the carrier by an ultrasonic-assisted immersion method to prepare the catalyst.

The invention discloses high-temperature-resistant silicon molybdenum ferrite nodular cast iron for a steam turbine and a preparation technology therefor. The nodular cast iron comprises components: 3.0-3.5% of C, 2.8-3.2% of Si, less than 0.2% of Mn, less than 0.040% of P, less than 0.015% of S, 0.5-0.8% of Mo, less than 0.010% of Re, 0.040-0.055% of Mg, and 0.004-0.007% of Sb, the balance being iron and residual elements. The preparation technology comprises furnace charge matching; intermediate frequency induction furnace fusing; spheroidizing and addition of first inoculation ferrosilicon; control of contents of elements; pouring into a pulling runner box for secondary inoculation; casting moulding. The obtained nodular cast iron has good combination properties and a low cost, the nodularity reaches more than 80% of the nodularity prescribed by GB/T9441-2009 nodular cast iron metallographic examination, the ferrite amount is more than 90%, and normal temperature and high temperature mechanical properties meet production requirements.

The invention discloses a preparation method of a molybdenum-sulfur complex lubricating oil additive with high molybdenum content. The preparation method comprises the following steps: I, preparing a mixed liquid A from a hexavalent molybdenum compound, a sulfur-containing compound and distilled water, and then adjusting a pH value; II, adding dialkyl amine into the mixed liquid A which is subjected to pH value adjustment, then stirring, and then adding a phase transfer catalyst to obtain a mixed liquid B; III, under the protection of a nitrogen atmosphere, dropwise adding carbon disulfide into the mixed liquid B to obtain a mixed liquid C; and IV, standing the mixed liquid C till the mixed liquid C is layered, removing a water phase, washing an organic phase by virtue of an alkaline solution and an organic solvent, then distilling, and drying to obtain the high-molybdenum-content molybdenum-sulfur complex lubricating oil additive of which the mass percentage content of molybdenum is not less than 10%. The preparation method disclosed by the invention is simple in preparation process, and is favorable for industrial production; and the prepared molybdenum-sulfur complex lubricating oil additive has relatively high molybdenum content and good oil solubility, and after the additive is added into lubricating oil, the anti-wear and friction reduction properties of the lubricating oil can be greatly improved.

The invention discloses a method for lixiviating molybdenum from roasted molybdenite. The method comprises the following steps of: 1, uniformly mixing the roasted molybdenite, ammonium carbonate and deionized water at a certain mass ratio, and then stirring for 40-70 minutes under the condition that the temperature is 70-90 DEG C to obtain a turbid liquid; 2, filtering to obtain a filter cake and filter liquor; 3, washing the filter cake by adopting ammonia water, then uniformly mixing the washed ammonia water with the filter liquor to obtain a mixed liquor; 4, regulating the pH value of the mixed liquor to 8.0-8.5, uniformly stirring, then carrying out sedimentation treatment, and taking a supernatant to obtain molybdenum lixivium. The process disclosed by the invention is simple, easy to operate, high in repeatability and suitable for large-scale industrial production, adopts the ammonium carbonate as a lixiviant, and can be used for greatly reducing the sludging ratio and the molybdenum content of dregs by regulating and optimizing the lixiviating process, and achieving the molybdenum lixiviating rate as high as more than 98%.

The invention discloses a high-activity catalyst Fe2O3-MoO3-Bi2SiO5 for preparing epoxypropane through gas-phase epoxidation of propylene and a preparation method thereof. The catalyst is used in a reaction for preparing epoxypropane through propylene gas-phase epoxidation by taking air, molecular oxygen or N2O as an oxidizing agent, the reaction condition is mild, no inhibitor is added, and the catalyst has relatively high catalytic activity. According to the catalyst, Bi2SiO5 nanosheets serve as a carrier, MoO3 serves as an active component, Fe2O3 serves as an auxiliary, the Si/Bi mole ratiois 0.1-1, the Mo/Bi mole ratio is 0.01-1, and the Fe/Mo mole ratio is 0.05-1. The carrier Bi2SiO5 nanosheet is synthesized by adopting a hydrothermal method, and for the active component MoO3 and theauxiliary agent iron oxide, molybdenum and iron precursors are impregnated on the carrier by adopting an ultrasonic-assisted impregnation method to prepare the catalyst.

The invention discloses a catalyst Fe2O3-MoO3-Bi2SiO5/SiO2 for preparing propylene epoxide by propylene gas-phase epoxidation at ordinary pressure and a preparation method of the catalyst. The catalyst is applied to a reaction of preparing propylene epoxide from air, molecular oxygen or N2O as an oxidizing agent by the propylene gas-phase epoxidation, the reaction conditions are mild, inhibitors are not required, and the catalyst has higher catalytic activity. The catalyst adopts a Bi2SiO5-containing SiO2 mesoporous material Bi2SiO5/SiO2 as a supporter, MoO3 as an active component and Fe2O3 asan auxiliary, and in terms of mole composition of the catalyst, Si/Bi is 50, Mo/Bi is 1-10, and Fe/Mo is 0.05-1. The supporter Bi2SiO5/SiO2 is synthesized with a hydrothermal method, the active component MoO3 and the auxiliary iron oxide impregnate Mo and Fe precursor to the supporter with an ultrasonic assisted impregnation method, and the catalyst is prepared.

The invention relates to a molybdenum concentrate screening method which aims to solve the problems that a molybdenum concentrate screening method in the prior art is low in utilization rate of resources and low in recovery rate of molybdenum concentrates. The method comprises the following steps of: (1) pretreatment on molybdenum raw-ores: carrying out treatment on the molybdenum raw-ores so as to obtain fine ores; (2) ore grinding and grading: carrying out ore grinding on the fine ores so as to obtain an ore grinding product, and then carrying out closed grading on the ore grinding product by using a hydrocyclone so as to obtain an overflow object; (3) flotation: adding a flotation reagent in the overflow object subjected to ore grinding and grading in a flotation column, and carrying out molybdenum ore rough-concentration and dense grading on the obtained mixture so as to obtain a rough concentrate; (4) fine selection: after the rough concentrate obtained in the step (3) is subjected to a regrinding process, carrying out fine selection on the rough concentrate for two times, then carrying out scavenging on the obtained product for three times so as to obtain a molybdenum concentrate; and (5) concentrate dehydration; concentrating the molybdenum concentrate, and carrying out further squeezed dehydration on the molybdenum concentrate so as to obtain a molybdenum concentrate finished product. The screening method disclosed by the invention is high in utilization rate of molybdenum raw-ores; and less waste residues and waste dust are produced in a process of screening, therefore, the production environment is friendly.

The invention discloses a method for advancedly removing molybdenum from a manganese sulfate solution. The method for advancedly removing the molybdenum from the manganese sulfate solution is carriedout according to the following steps of after a pH value of the manganese sulfate solution is adjusted, adding a molybdenum removal agent into the solution, and conducting stirring and filtering to obtain filter liquor, namely a purified manganese sulfate solution; and therefore, the requirement of purifying the manganese sulfate solution can be met, and in the molybdenum removal process, the solution does not need to be heated. The method for advancedly removing the molybdenum from the manganese sulfate solution has the advantages that the procedures are simple, the cost is low, the efficiency is high, no pollution is generated, the defects of existing methods are overcome, and the requirements of the molybdenum content of manganese sulfate for producing a high-purity manganese-bearing material are met.

The invention discloses a method for reducing molybdenum content after chamber maintenance. The method comprises the following steps of: S1, carrying out chamber maintenance, wherein the chamber maintenance step at least comprises a cleaning substep of injecting first process gas and discharging the first process gas so as to reduce the content of metal impurity ions in a chamber, and the cleaning step is repeated for multiple times; S2, detecting the molybdenum content in the chamber to measure the content of molybdenum ions in the chamber; and S3, carrying out molybdenum element cleaning, so that the content of molybdenum ions in the cavity is reduced.

The invention discloses a method for purifying and removing molybdenum from ammonium rhenate. The method comprises the following steps: 1, preparing a molybdenum-containing ammonium rhenate solution; 2, preparing a multi-stage series ion exchange column group, and enabling an HNO3 solution to flow through the multi-stage series ion exchange column group to obtain an H < + > type multi-stage series ion exchange column group; 3, enabling the ammonium rhenate solution containing molybdenum to flow through an H + type multi-stage series ion exchange column group to adsorb and remove molybdenum, so as to obtain a pure perrhenic acid solution; 4, the pure perrhenic acid solution is sequentially subjected to pH adjustment and evaporative cooling crystallization, and ammonium rhenate crystals are obtained. The method comprises the following steps: converting a molybdenum-containing ammonium rhenate solution into an acidic perrhenic acid solution through first-stage resin, converting molybdenum in the solution into MoO2 < 2 + > ions, removing most molybdenum through second-stage resin exchange, purifying residual trace molybdenum through third-stage and later-stage resin, neutralizing with ammonia water, evaporating, cooling and crystallizing to obtain the ammonium rhenate with low molybdenum content, and the requirement of the aeronautical material on the low molybdenum content in the metal rhenium is met.

The invention discloses a tungsten-molybdenum separation method which comprises the following steps: S1, carrying out primary evaporative crystallization on a tungsten-molybdenum-containing feed liquid, and carrying out primary filtration to obtain primary mother liquor and primary crystallized ammonium paratungstate; S2, performing secondary evaporative crystallization on the primary mother liquor, and performing secondary filtration to obtain secondary mother liquor and secondary crystallized ammonium paratungstate; S3, performing tungsten-molybdenum separation on the secondary mother liquor obtained in the step S2; S4, calcining the secondary crystallized ammonium paratungstate obtained in the step S2 into yellow tungsten, and adding at least one part of yellow tungsten into the feed liquid in the step S1; and S5, calcining the primary crystallized ammonium paratungstate obtained after the yellow tungsten in the step S4 is added into the step S1 into yellow tungsten, and dissolving the obtained yellow tungsten into stronger ammonia water to obtain ammonia-soluble second-stage liquid. According to the tungsten-molybdenum separation method disclosed by the invention, a tungsten-molybdenum ratio in the evaporated and crystallized high-molybdenum ammonium paratungstate is increased by adopting a two-time evaporative crystallization mode, the proportion of molybdenum entering a subsequent molybdenum removal system is reduced, and the subsequent molybdenum removal cost is reduced.

The invention provides a method for separating molybdenum from aluminium in alkaline solution. The method is characterized in that alkali metal hydroxide is added; the consistency of free alkali is controlled within 1.20-1.80mol/L; according to the molar ratio of 0.95-1.05 of Al:Si, alkali metal silicate solution is added under mixing condition at the normal temperature within 3 hours; the mixing condition is kept, the temperature is increased to the gelatinizing temperature of 50-80 DEG C and the gelatinizing temperature is kept for 2 hours; subsequently, the temperature is increased to the crystallization temperature of 90-110 DEG C and the crystallization temperature is kept for 3-5 hours; after filtration and separation, aluminosilicate precipitate and molybdate solution are obtained; after separation, the content of molybdenum in the aluminosilicate precipitate is reduced to below 0.2%wt, the content of aluminium or silicon in the filtrate is reduced to below 0.5g/L, the precipitation rate of the aluminium or the silicon is more than 98%. More than 98% of the soluble molybdate in the molybdenum filtrate is remained, thus achieving good separation coefficient. The method is suitable for recovering molybdenum element from waste catalyst.