CN103964875A - Raw material composition for graphite-silicon carbide crucible and manufacturing process thereof - Google Patents

The feedstock composition of graphite-silicon carbide crucible and manufacturing process thereof

Technical field

The present invention relates to a kind of melting used for non-ferrous metal crucible, be specifically related to a kind of feedstock composition and manufacturing process thereof of graphite-silicon carbide crucible.

Background technology

Clay-plumbago crucible for non-ferrous metals such as melting gold and silver, copper, aluminium, zinc and alloys thereof, as far back as the thirties in 20th century, just produced, production method is through pulverizing, batching, manual spinning or roller-compaction raw material, be dried, burn till, brush oil moistureproof, with graphite, clay, pyrophyllite grog, or bauxite chamotte, simple substance silica flour, or ferrosilicon powder is antioxidant, and water forms according to certain ratio proportioning.Afterwards, with the silicon carbide of part, replaced bauxite chamotte, to improve quality, increased thermal conductivity.This method production process is complicated, and blank needs slowly to dry, and consumes the energy many, and work in-process loss is large, and distortion is many, the production cycle long (general 25-30 days).

At present, isostatic pressing is state-of-the-art crucible moulding process in the world.Be generally to take resol, tar or pitch as bonding agent, take graphite-silicon carbide crucible that graphite and silicon carbide is main raw material, this kind of crucible void content is low, and density is large, homogeneous, and erosion resistance is strong.But resin, tar and pitch can discharge a large amount of harmful flue dust, contaminate environment in sintering process.

Summary of the invention

In order to address the above problem, the object of the invention is to, a kind of feedstock composition and manufacturing process thereof of graphite-silicon carbide crucible is provided, technique is simple, with short production cycle, produces environmentally safe in manufacturing processed without harmful flue dust.

The feedstock composition of described graphite-silicon carbide crucible, comprises the raw material of following weight percent: crystalline flake graphite 40%-50%, silicon carbide 20%-50%, simple substance silica flour 4%-10%, boron carbide powder 1%-5%, clay 5%-15%; The carbon content of described crystalline flake graphite is greater than 90%, and granularity is 50-100 order; The purity of described silicon carbide is greater than 90%; Described clay is any one or a few the mixture in kaolin, Guangxi white clay, kieselguhr.

Described feedstock composition also comprises that weight percent is the interim bonding agent of 6%-12%, and described interim bonding agent is the mixture of any one or two kinds in polyvinyl alcohol water solution, the xylogen aqueous solution, interim bonding agent add the plasticity-that has increased pug.

The manufacturing process of described graphite-silicon carbide crucible, comprises the following steps:

(1) raw material of getting ready is mixed, make pug;

(2) by above-mentioned pug ageing mixture one day, and be dried into the qualified pug that fugitive constituent is 1%-2%;

(3) qualified pug is packed in mould, put into isostatic pressing machine cylinder, compression moulding under 50MPa-100MPa pressure;

(4) demoulding, dries blank;

(5) at crucible surface, apply anti-oxidation glaze while hot, obtain crucible work in-process;

(6) above-mentioned gained work in-process are put into the naked burning of Sweet natural gas kiln, firing temperature is 1000 ℃-1200 ℃, makes glaze be molten into glass glaze, must burn till product;

(7) check, packing, warehouse-in.

The feedstock composition of graphite-silicon carbide crucible provided by the invention and manufacturing process thereof, its beneficial effect is, technique is simple, the crucible of preparation is homogeneous, and density is large, and void content is low, heat conduction is fast, corrosion resistance is strong, and adopts clay as bonding agent, has avoided resol or tar to make bonding agent and in sintering process, has decomposed the harmful flue dust of release and contaminate environment.

Embodiment

Below in conjunction with three embodiment, the feedstock composition of graphite-silicon carbide crucible provided by the invention and manufacturing process thereof are described in detail.

Embodiment 1

The feedstock composition that the present embodiment is prepared graphite-silicon carbide crucible comprises the raw material of following weight percent: crystalline flake graphite 47%, silicon carbide 36%, simple substance silica flour 8%, boron carbide powder 2%, kaolin 7%.

The manufacturing process of described graphite-silicon carbide crucible comprises the following steps:

(1) raw material of getting ready is put into mixing machine and mix, add water, mix, make pug;

(2) by above-mentioned pug ageing mixture one day, and to be dried into fugitive constituent be 1.4% qualified pug;

(3) qualified pug is packed in mould, beat closely knitly, put into isostatic pressing machine cylinder, compression moulding under 70MPa pressure;

(4) demoulding, is placed on blank on drying cart, enters in dry kiln and is slowly warmed up to 120 ℃, thoroughly dries;

(5) at crucible surface, apply anti-oxidation glaze while hot, obtain crucible work in-process;

(6) above-mentioned gained work in-process are put into the naked burning of Sweet natural gas kiln, firing temperature is 1050 ℃, makes glaze be molten into glass glaze, must burn till product;

(7) check, packing, warehouse-in.

Embodiment 2

The feedstock composition that the present embodiment is prepared graphite-silicon carbide crucible comprises the raw material of following weight percent: crystalline flake graphite 45%, silicon carbide 29%, simple substance silica flour 6%, boron carbide powder 2%, Guangxi white clay 10%, polyvinyl alcohol water solution 8%.

The manufacturing process of described graphite-silicon carbide crucible comprises the following steps:

(1) raw material of getting ready is put into mixing machine and mix, add water and polyvinyl alcohol water solution, mix, make pug;

(2) by above-mentioned pug ageing mixture one day, and to be dried into fugitive constituent be 1.5% qualified pug;

(3) qualified pug is packed in mould, beat closely knitly, put into isostatic pressing machine cylinder, compression moulding under 80MPa pressure;

(4) demoulding, is placed on blank on drying cart, enters in dry kiln and is slowly warmed up to 120 ℃, thoroughly dries;

(5) at crucible surface, apply anti-oxidation glaze while hot, obtain crucible work in-process;

(6) above-mentioned gained work in-process are put into the naked burning of Sweet natural gas kiln, firing temperature is 1100 ℃, makes glaze be molten into glass glaze, must burn till product;

(7) check, packing, warehouse-in.

Embodiment 3

The feedstock composition that the present embodiment is prepared graphite-silicon carbide crucible comprises the raw material of following weight percent: crystalline flake graphite 42%, silicon carbide 26%, simple substance silica flour 5%, boron carbide powder 4%, kieselguhr 13%, the xylogen aqueous solution 10%.

The manufacturing process of described graphite-silicon carbide crucible comprises the following steps:

(1) raw material of getting ready is put into mixing machine and mix, add water and the xylogen aqueous solution, mix, make pug;

(2) by above-mentioned pug ageing mixture one day, and to be dried into fugitive constituent be 1.3% qualified pug;

(3) qualified pug is packed in mould, beat closely knitly, put into isostatic pressing machine cylinder, compression moulding under 90MPa pressure;

(4) demoulding, is placed on blank on drying cart, enters in dry kiln and is slowly warmed up to 120 ℃, thoroughly dries;

(5) at crucible surface, apply anti-oxidation glaze while hot, obtain crucible work in-process;

(6) above-mentioned gained work in-process are put into the naked burning of Sweet natural gas kiln, firing temperature is 1150 ℃, makes glaze be molten into glass glaze, must burn till product;

(7) check, packing, warehouse-in.