CN86103562A - Process for quickly synthesizing fine diamond - Google Patents

Abstract

A process for quickly synthesizing fine diamond relates to a method for synthesizing artificial diamond. At present, a crushing method and a production process for directly synthesizing fine diamond exist. The invention is characterized in that: the pressure and power are adjusted timely and accurately according to the current drop and the distribution of the diamond on the cross section of the synthesis rod, and the synthesis process is completed in a short heat preservation time. The fine diamond has high yield and good quality.

Description

The technology of rapidly synthesizing fine diamond

The present invention relates to a kind of man-made diamond technology

At present, domesticly generally adopt second-rate (JR ₁Type, JR ₂Type) diamond of granularity thick (120 orders are with thick) obtains fine diamond (second development and performance test that the new Xue Yong of national high pressure academic discussion proceeding Wang De advances the long glomerocryst of φ 6 * 10m/m, page 2) through fragmentation.Fine diamond that obtains like this and micro mist contain considerable impurity, and crystalline form is also undesirable; Changsha Metallurgy Institute of Ministry of Metallurgical Industry has been studied " the directly technology of synthesizing fine diamond ", and (see Chinese patent application number: 85100406), changed above-mentioned technology, directly synthesizing fine diamond is the reform to old technology.But its synthesis cycle is long, and product fineness is thin inadequately; Soviet Union's been reported is crossed with powder catalyst and is produced fine diamond (п р и х н а А, И etc., К в о п р о с у О р о л и к р и с т а л л т о в г р а ф и т а В П р о ц e с с e С И и т e з а а л м а з а-С И и т e т и ч e с к и e а л м а з а 1974, № 4), said the rugosity and the intensity of product in the literary composition, but do not report output, so difficult thoroughly evaluating synthetic effect.

The objective of the invention is to: overcome the shortcoming in the prior art, work out a kind ofly in very short soaking time and synthesis cycle, grow the output height.Particle is thin, the technology of the technology of the measured fine diamond of matter-a kind of rapidly synthesizing fine diamond.

This technology mainly by get the raw materials ready, assemble, synthesize, acid treatment and aftertreatment five processes formed.

1. procedure for preparation:

Starting material of the present invention are agalmatolite ring, conduction steel loop (liner agalmatolite), graphite flake, insulation sheet, agalmatolite piece, give molded rod.Above-mentioned materials all needs to give processing can adapt to processing requirement, that is: (1), agalmatolite ring, conduction steel loop, graphite flake, agalmatolite piece method baking and preservation routinely; Graphite in the pre-molding rod, catalyst (Ni ₇₅Mn ₁₅Cu ₁₀Or N ₇₀Mn ₂₅Co ₅) be approximately 1: 4: 0.13 with the ratio of water (making binding agent and lubricant).This ratio can differently according to circumstances be done suitably change, and its forming pressure opticoel body varies in size, and is 5～10 tons; Graphite Powder 99 in the insulation sheet, the ratio of pyrophyllite powder are about 65: 35, and the consumption of water glass (making binding agent) is 20～24% of Graphite Powder 99 and a pyrophyllite powder weight sum.Oven dry moisture content in advance after the insulation sheet compression moulding, further sintering under comparatively high temps then, sintering temperature is relevant with sintering time, and sintering time is long, and then temperature can be hanged down, and on the contrary, sintering temperature is higher.For example, when sintering time was 1～2 hour, then sintering temperature was roughly 300～500 ℃.Insulation sheet behind the sintering should be worn into the thickness of unified specification, looks the requirement of production to diamond grit, and looks the size of synthetic power and electric current, and the thickness of insulation sheet is got 1～2 millimeter.But the density of insulation sheet is should be as far as possible consistent, promptly be roughly 1.7～2.0 grams/(centimetre) ³

2. assembling procedure:

Accompanying drawing is seen at the position of each material assembling, that is: in the agalmatolite cavity (1) of garden cylindricality, it is placed in the middle to give molded rod (6), symmetrical up and down, end positions dress insulation sheet (4) at moulding stick, the outside dress graphite flake (3) of insulation sheet, at the outside of graphite flake dress conduction steel loop (2), outermost is the agalmatolite ring again.

In the process of assembling, must be noted that following matters: cooperating between (1), agalmatolite ring and the agalmatolite piece is too not tight, and the moisture content in the pre-molding rod is run out of when toasting easily; (2), the thickness of graphite flake should be suitable, should make graphite flake not account for too much cavity volume, makes insulation pitch of fins steel loop that certain distance is arranged again, be generally between every thick 1～3 centimetre; (3), when cavity is big, the middle part of pre-molding rod can be again with the graphite flake of suitable thickness or be incubated sheet it is separated.Giving molded rod and can suppress at twice at this moment; (4), after assembly block assembling finishes, should be put in the baking oven as early as possible and toast, storing temperature is relevant with storing time, is generally 120～140 ℃.A few hours to tens to be baked hour, when not exitting bubble, then can think and dry by the fire.

3. synthesis procedure:

After assembly working finishes, can synthesize.The resultant current of this operation is about 1400 ± 100A, and gauge pressure is 1250～1300Kg/Cm ²Carry out a ftercompction in synthetic mid-term, pressure thereafter is 1300～1380Kg/Cm ², promptly mend tens kilograms of pressure; Be incubated after synthetic, soaking time is 3 minutes 40 seconds to 4 minutes and 30 seconds; Adamantine synthetic effect can be judged by two kinds of methods: the one, synthetic rod (sampling) is broken direct viewing growth of diamond phenomenon along the middle part.The 2nd, when operation, observe electric current decline situation, 40～80A generally should descend.

4. acid treatment operation:

Prior art is adopted in acid treatment of the present invention, but the step difference of removing graphite, and concrete grammar is: (1), remove catalyst with concentrated nitric acid (water doubles); (2), eluriate when removing graphite, wash in a pan graphite to the greatest extent as far as possible, can make a part of diamond (be about diamond total amount 10%) enter washing lotion; Pour the diamond (account for diamond total amount 90%) of washing in a pan graphite into first beaker; Again the residue diamond in the washing lotion is remake elutriation, make it to stay more graphite, reducing carat loss as far as possible, and pour these diamonds into second beaker; In first beaker, add limpid sulfur waste acid, waste nitric acid mixed solution (can replenish new nitric acid in right amount), till being heated to Mao Baiyan on the electric furnace, leave standstill some minutes, (Graphite Powder 99 that suspends in the waste liquid is along with one of waste liquid goes to remove top waste liquid, can remove quite a few graphite), handle according to a conventional method with new sulfuric acid, nitric acid mixed solution again; The method that diamond in second beaker removes graphite is identical with first beaker basically, just can carry out several times spent acid more and handle; At last, the diamond of removing graphite is gone agalmatolite, washing, oven dry with hydrofluoric acid, promptly obtain the diamond of pure Net.

5. adamantine aftertreatment:

The diamond of above-mentioned gained remains at many crystal stock bodies.In order to destroy the crystal stock body, need do aftertreatment: carried out ball milling 6～8 hours (wherein φ 25 steel balls mix use with φ 14 steel balls) with ball mill, make crystal stock become monomer, and the diamond behind a small amount of diamond refinement, the ball milling is handled again through hydrochloric acid or perchloric acid, washing, oven dry or screening, promptly obtain equivalance shape better, the granularity diamond of thin (≤180 orders can reach more than 80%).

The invention has the advantages that: generated time is short, and output height, the quality of fine diamond are good, thereby good in economic efficiency.For example, when adopting same φ 16 cavity agalmatolites, platform machine per unit area yield average comparable No. 85100406 high 1 carat, synthesis cycle reduces by 1～2 minute (being equivalent to the shortening cycle 20%); Aspect crystalline form, its equivalance can reach (120～280 order) more than 95%; In economic benefit, the separate unit press was overcharged 14.8 ten thousand yuan of taxes and profits than crush method in 1 year, overcharged ten thousand yuan of taxes and profits 6-7 than " the directly technology of synthesizing fine diamond ".

The drawing explanation:

1. agalmatolite ring 2. conduction steel loops

3. graphite flake 4. is incubated sheets

5. agalmatolite piece 6. gives molded rod

Embodiment:

In the somewhere, adopt φ 16 cavitys, the used water glass amount of its insulation sheet is 23% of its Graphite Powder 99 and a pyrophyllite powder weight sum, is Ni to the catalyst that gives molded rod ₇₅Mn ₁₅Cu ₁₀Working pressure is 8 tons, is thick 1.4 millimeters of 400 ℃, sheet to the sintering temperature of insulation sheet, sintering 90 minutes; When assembling, the distance between insulation sheet and the steel loop is 2 centimetres, and the storing temperature of assembly block is 135 ℃, and baking is more than 10 hours.At synthesis procedure, synthesis cycle 4 minutes is incubated 80 seconds, and the gained diamond is carried out acid treatment and aftertreatment.The ball milling time of aftertreatment is 6.5 hours, and the output of products obtained therefrom and granularity see Table 1, table 2, and equivalance shape is good, is yellow-green colour.

Claims (4)

1, a kind of technology of rapidly synthesizing fine diamond relates to a kind of method of man-made diamond.Up to now, adopted get the raw materials ready, assemble, synthesize, the direct synthesizing fine diamond of operation such as acid treatment and aftertreatment.The invention is characterized in: in synthesis procedure, the control suitable current, voltage and soaking time are synthesized.

2, according to the technology described in the claim 1, it is characterized in that: resultant current is about 1400 ± 100A, in building-up process, and its value decline 40～80A;

3, according to the technology described in the claim 1, it is characterized in that: adopt 1250～1300Kg/Cm ²Gauge pressure, and carry out a ftercompction in synthetic mid-term, make it to reach 1300～1380Kg/Cm ²;

4, according to the technology described in the claim 1, it is characterized in that: soaking time is 70～120 seconds, and the insulation cycle is 3 minutes 40 seconds to 4 minutes and 30 seconds.

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