37results about How to "Achieve selective removal" patented technology

The present invention relates to a corrosive agent of an HfSiON high-K gate dielectric material and a corrosion method by using the corrosive agent, which belong to the technical field of integrated circuit manufacture. The corrosive agent comprises 0.19-4.83 percent by weight of hydrofluoric acid. The corrosion method by using the corrosive agent comprises the following steps: forming the HfSiON high-K gate dielectric material on an Si substrate, an Si / SiO2 interface layer or Si / SiON interface layer, and soaking the HfSiON high-K gate dielectric material in the corrosive agent for wet method corrosion. The corrosive agent is used for carrying out corrosion on the HfSiON high-K gate dielectric material and can reduce the hydrolysis of the hydrofluoric acid, thereby the corrosion speed of the HfSiON high-K gate dielectric material is improved, the corrosion speed of field oxide region SiO2 can be reduced, and the selection ratio of HfSiON to the field oxide region SiO2 can be further improved.

The invention discloses a method for preferably removing arsenic in lead and antimony smoke. The method comprises the following steps that firstly, sulphur and the lead and antimony smoke are mixed according to the mass ratio of 0.01-0.5:1, then the mixture is added into a sodium hydroxide solution to be leached, and meanwhile the temperature of the solution is kept within the range from 50 DEG C to 100 DEG C; secondly, liquid and solid separation is carried out on the solution leached in the first step, and a leaching agent and leaching residues are obtained; the leaching residues are washed, washing water obtained after washing is completed and the leaching agent are mixed and cooled to the room temperature, and filtering is carried out to obtain sodium arsenate crystal and crystalline liquid; and the crystalline liquid is used for leaching of the lead and antimony smoke in the first step. According to the technology method, the loss of valuable metal such as lead, antimony and zinc in the arsenic leaching and removing process is reduced through the adding of sulphur, meanwhile, the arsenic removing rate is increased, and selective removing of arsenic is achieved. The leaching rate of arsenic can reach 99% or more, and the content of arsenic in the leached residues can be reduced to 0.1% or lower.

The invention relates to a method for removing arsenic from arsenic containing smoke under fluidization. The method comprises the following steps: firstly, drying the arsenic containing smoke, fluidizing the arsenic containing smoke by using a gas flow, controlling the proportion of protective gases to reducing gases in the gas flow, and reducing and volatilizing arsenic; and then directly volatilizing arsenic in the presence of the protective gases, collecting dust in smoke generated during volatilizing arsenic at a high temperature, and collecting arsenic at a low temperature to obtain arsenic trioxide, wherein the residue generated during volatilizing arsenic serves as a raw material for recovering other valuable metals. Because involatile arsenic pentoxide is completely converted into volatile arsenic trioxide, and the further reduction of arsenic trioxide is avoided, arsenic can be removed from the arsenic containing smoke efficiently. Residue and smoke generated from the treatment of arsenic containing smoke are used as a raw material for recovering valuable metals and an arsenic trioxide product respectively, and thus no secondary pollution is caused.

The invention discloses a compound of lanthanum molybdate and ferromagnetic materials and application of preparation and adsorption phosphorus removal, belonging to the technical field of phosphorus removal from sewage and wastewater. The preparation method of the composite comprises the following steps of: dispersing ferromagnetic materials in water, adding lanthanum salt, fully mixing, adding ammonium molybdate, sodium molybdate or potassium molybdate, adjusting the pH to 8-10, and performing coprecipitation reaction to obtain lanthanum molybdate. The reaction system is placed in a reactionkettle and reacts under the condition of 180 DEG C or more to obtain a composite of lanthanum molybdate and ferromagnetic materials. According to the composite disclosed by the invention, the selective adsorption function of lanthanum molybdate on phosphate radicals is utilized, and the superparamagnetism of ferromagnetic ore is utilized at the same time, so that the adsorbent can be separated andregenerated under the condition of an external magnetic field after phosphorus is adsorbed and removed in sewage, and the effect of recycling the adsorbent is realized.