4results about How to "Reduce supersaturation" patented technology

The application provides a silicon carbide crystal growth method and a growth device thereof, and belongs to the technical field of silicon carbide single crystal growth. The growth method comprises the following steps: providing a crystal growth device, mounting a silicon carbide seed crystal on a seed crystal holder, and cyclically performing a preset number of redox pretreatments; the redox pretreatment comprises the following steps: using an oxidizing gas to perform oxidation treatment on a growth surface of the silicon carbide seed crystal to obtain an oxidation layer, and then using a reducing gas to perform reduction treatment on the oxidation layer and to desorb; after the cyclic execution, a pit is generated at a basal plane dislocation emergence of the seed crystal surface, and a pretreated seed crystal is obtained; an asymmetric structure is adopted to fill silicon carbide polycrystal materials at the bottom of a crucible in the crystal growth device; a physical vapor transport method is used for crystal growth, so that the growth rate of a central region of the crystal is greater than that of an edge region, and a finished product is obtained. The device for the above method is also provided. The problems that the existing BPD cannot be effectively removed, the existing process cost is high, and the yield is low are solved.

The application relates to the technical field of cement materials, and particularly discloses a high ore fused stone ferrite aluminate cement material and a preparation method thereof. The cement material is prepared by jointly grinding and treating high belite ferrite aluminate cement clinker and a modifier. The modifier is composed of succinyl phosphonate, a quaternary ammonium salt and an aluminum source. The molecular formula of the succinyl phosphonate is HOOC-CH2-CH2-CO(PO3H2). The modifier composed of succinyl phosphonate, a quaternary ammonium salt and an aluminum source is used to perform mechanochemical coupling modification on the belite ferrite aluminate cement clinker, multi-level interface interaction occurs under the induction of mechanical force, directional poisoning and growth inhibition of calcium aluminate crystal nuclei are realized, the early strength of the cement is maintained, and the volume stability of the cement material is significantly improved.

The invention relates to the technical field of cement materials, and particularly discloses a high-ore-melting-stone iron aluminate cement material and a preparation method thereof. The cement material is prepared by grinding high belite sulfur iron aluminate cement clinker and a modifier together. The modifier is composed of succinyl phosphonate, quaternary ammonium salt and an aluminum source. The molecular formula of the succinyl phosphonate ester is HOOC-CH2-CH2-CO (PO3H2). According to the invention, a modifier composed of succinyl phosphonate, quaternary ammonium salt and an aluminum source is used for carrying out mechanochemical coupling modification on belite pyrite aluminate cement clinker, and multi-level interface interaction occurs under the induction of mechanical force, so that directional poisoning and growth inhibition of ettringite crystal nucleus are realized; and the volume stability of the cement material is remarkably improved while the early strength of the cement is maintained.

The application relates to the technical field of iron phosphate preparation, in particular to a preparation method of iron phosphate dihydrate containing an orthorhombic crystal form, which comprises the following steps: adding a mixed solution of a phosphate and an oxidizing agent into a ferrous solution, controlling the amount of the oxidizing agent, so that there is no ferrous ion in the reaction solution after the mixed solution is added; adding an alkali liquor to the reaction solution to adjust the pH value, and keeping the temperature at 50-60 DEG C for 1-2 hours; filtering and washing the prepared slurry to obtain a solid; after the solid is pulped, adding phosphoric acid to adjust the pH value, and reacting at 80-100 DEG C for 1-2 hours; and filtering, washing and drying the reaction product to obtain the iron phosphate dihydrate containing the orthorhombic crystal form. The preparation method of the iron phosphate dihydrate containing the orthorhombic crystal form is simple in process, short in technological process, low in reaction temperature, and does not need to add a surfactant in the reaction, so that the iron phosphate dihydrate containing the orthorhombic crystal form can be prepared.