CN85103851A - Process for Directly Synthesizing Fine Diamond - Google Patents

Abstract

A process for directly synthesizing fine diamond belongs to the field of artificial synthesis of diamond. The invention adopts powder catalyst, powder graphite is pressed into a prepressing molding rod according to high proportion catalyst, assembled in pyrophyllite blocks with special heat preservation sheets at two ends, synthesized according to special process conditions, and finally the obtained product is treated by acid and ground to obtain the fine diamond. Compared with the existing method for crushing rough diamond, the yield is higher than 1/3, the equal volume of 120-280 meshes is more than 90%, the impurity content is low, and the process is stable.

Description

The technology of direct synthesizing fine diamond

Directly the technology of synthesizing fine diamond belongs to the artificially synthesizing diamond field.

At present, domesticly generally adopt second-rate (JR ₁Type, JR ₂Type), the diamond of granularity thick (120 orders are with thick) is through broken (have cry shaping) and acquisition fine diamond (see " second national high pressure academic discussion proceeding ", 1983,6, Chengdu).Such fine diamond is impure many, and crystalline form is also undesirable; Rare abroad about the report of producing fine diamond with powder catalyst and powder graphite.The Soviet citizen reported and used the powder catalyst synthesizing fine diamond, grade is that 0.05～0.08 millimeter monocrystalline quantity can reach 97%, but do not report diamond output, thereby the synthetic effect that is difficult to the thoroughly evaluating fine diamond (is seen " П pu-XHa AN etc., K Bonpocy O no л ukpucTan л uToB Tpa φ uTa B npouecce CuHTe

A anMa

A-CuH-TeTuyeckue anMa U, 1974 Bun4).

The objective of the invention is to: seek a kind of rational packaging technology and synthesis technique, cooperate and adopt powder catalyst, overcome the shortcoming in the prior art, obtain the fine diamond of good quality, high yield, adaptation user needs with good synthetic performance.

Directly the technology of synthesizing fine diamond comprises raw-material preparation.Assemble according to processing requirement, the CONTROL PROCESS condition is synthesized and four of acid treatment are partly formed.The required starting material of technology are agalmatolite ring, conduction steel loop (liner agalmatolite), graphite flake, insulation sheet, agalmatolite piece and give molded rod.Above-mentioned starting material are answered stringent regulations, and model specification is Yan Ge And unanimity as far as possible.Wherein agalmatolite ring, conduction steel loop, graphite flake, agalmatolite piece toast according to a conventional method and preserve.Agalmatolite piece system adopts hole, straight-through and wheel chair access up and down garden; The ratio that gives catalyst, graphite and water in the molded rod (making binding agent and lubricant) is approximately 4～6: 1: 0.3～0.5, and forming pressure is looked and given the pressure bar size is 10～30 tons; The Graphite Powder 99 of insulation in the sheet, pyrophyllite powder the two by 1～3: 2～1 batchings, add water glass (making binding agent) by 1/4～1/6 of this compound weight again, after its compression moulding, oven dry moisture content earlier, further sintering under comparatively high temps again.Sintering temperature is relevant with sintering time, and sintering time is long, and then sintering temperature can be hanged down.If sintering time is 1～2 hour, then sintering temperature is roughly 300～500 ℃, and the insulation sheet behind the sintering should be worn into the thickness of certain specification according to the requirement of involutory success ratio and size of current and to the requirement of diamond grit.Usually, desirable 1～2 millimeter of the thickness of insulation sheet, its density should be even as far as possible.After each material finishes, promptly begin assembling.The present invention's requirement is carried out And by the mode shown in " accompanying drawing " and should be noted: agalmatolite too many (every end exceeds not give prominence to 1.5 millimeters) should not given prominence in the two ends up and down of A assembling rod (being the subassembly that the agalmatolite piece is wrapped), and projecting height should be consistent, so that when synthetic, grow the diamond that is distributed symmetrically; Cooperating between B, agalmatolite ring and agalmatolite piece and the conduction steel loop wanted suitably (cooperate when too tight, will have pyrophyllite powder to fall into and give on the molded rod, and moisture to be difficult for running out of during baking; Cooperate too pine, then conduct electricity steel loop and agalmatolite ring to drop out easily).The thickness of C, graphite flake is wanted suitably to be generally every thick 1.5～2.5 millimeters; When D, cavity are big, give molded rod middle part can be again with the graphite flake of suitable thickness or be incubated sheet it is separated, go the process of catalyst when being convenient to quicken acid treatment, E after the assembly block assembling finishes, should be put in the baking oven as early as possible and toast, its temperature is relevant with storing time, generally is advisable with 110～140 ℃.Continuous baking a few hours to tens hour.Assembly block then can synthesize after drying by the fire well.Synthetic transformation power, the change power parameter of adopting.Voltage-transforming method is: later stage pressure ratio pressure in early stage is high tens kilograms; The method of power variation is: about the ten seconds kinds of having a power failure at interval sometime before being warming up to 1 minute, and the power of the power ratio after having a power failure before having a power failure hangs down the scope of several scale values.Behind the end of synthesis, the acid treatment mode is with identical substantially usually.But when removing graphite, handle with the sulfur waste acid and the mixing acid of nitric acid earlier, remove few part graphite, eluriate with clear water again and remove graphite, handle to remove graphite fully with the mixing acid of new sulfuric acid, nitric acid at last with Xiization And.

The invention has the advantages that: with φ 16 cavitys and powder catalyst.Powder graphite obtains the diamond more than 3 carats, and the diamond that cavity that its rate ratio is onesize and slice catalyst, flake graphite are produced is high (to be supposed to desire to make the diamond of latter's gained unlikely too wide in the gap with this law qualitatively) more than 1/3; Aspect crystalline form, the fine diamond that this law obtains, its equivalance shape is no less than 90%(120～280 orders), and the equivalance shape of crush method gained fine diamond is very poor, even also be difficult to reach level of the present invention through shaping.Aspect the non-pneumatic foreign matter content, this law is than broken material much less, and getting analytic sample is that 240 and 280 purpose compounds analyze, and the non-pneumatic impurity of this law is 2.21%, and broken material then is 4.81%.On economic benefit, if 250 days (removing the repair time) three-shift of an annual product of press, with the crush method ratio, then a year economic benefit can reach about 6～100,000 yuan.

Drawing explanation: 1. agalmatolite ring, 2. conduction steel loop, 3. graphite flake,

4. insulation sheet, 5 agalmatolite pieces 6. give molded rod.

Embodiment: the second half year in 1984, our a selected unit has carried out existing Games and has implemented (with φ 16 cavitys), and concrete outcome is as follows: 8.10～8.60 carats of per unit area yields; Size composition accounts for 81～93% for≤120 orders, and≤240 orders account for 33.4～43%; Equivalance shape: 120～280 orders＞90%, product is a yellow-green colour, in the implementation process, process stabilizing.

Claims (10)

1, the technology of direct synthesizing fine diamond belongs to the technical field of artificially synthesizing diamond.In technology up to now, be to adopt slice catalyst and flake graphite to synthesize brait earlier, again through fragmentation, obtaining thin diamond, or use catalyst different and different technology synthesizing fine diamonds with the present invention.The present invention is characterised in that: adopt to have corresponding component requirement, the powder catalyst that performance requriements and physical specification require, powder graphite is pressed in high catalyst ratio and gives molded rod; And places rod the assembly block that has fixed structures such as special insulation sheet, after the processing requirement assembling, operate according to special synthetic technological condition, promote adamantine nucleation and growth thereof.At last, products obtained therefrom is passed through rational acid treatment ， And again through grinding, thereby obtain fine diamond.

2, according to " having corresponding component requires " carried in the claim 1, it is characterized in that: powder catalyst is Ni ₇₅Mn ₁₅Cu ₁₀Or Ni ₇₀Mn ₂₅Co ₅Deng, and powder graphite is that its carbon content is greater than 99%;

3, according to " performance requriements " carried in the claim 1, it is characterized in that: powder catalyst has good synthetic performance and antioxidant property, suitable temperature of fusion is arranged and carbon atom is had bigger solubleness; Powder graphite has higher degree of graphitization, is more than 0.9.

4, according to " physical specification " carried in the claim 1, feature is: the granularity major part of powder catalyst is about 46 orders.Few part can be little of 80 order to 120 orders, and the grade of corresponding powder graphite is less than 240 orders;

5, " be pressed into give molded rod in the high catalyst ratio " carried in the claim 1 is characterized in that: give molded rod and adopt a high proportion of catalyst to carry out proportioning, promptly catalyst was not less than 4: 1 with the ratio of graphite.Use water as their binding agent and lubricant, the water yield should suit, and has several globules to be extruded to suitable during with each die mould;

6, according to " the special insulation sheet " carried in the claim 1, it is characterized in that: by a certain percentage Graphite Powder 99, pyrophyllite powder and water glass are mixed, repressed forming, its thickness should be consistent as far as possible with density.Graphite Powder 99 in the insulation sheet is 1～3: 2～1 with the ratio of pyrophyllite powder, and the consumption of water glass is suitable with 1/4～1/6 of Graphite Powder 99 and pyrophyllite powder gross weight, and the insulation sheet Yet-have that suppresses need be through oven dry and roasting;

7, according to " assembly block of a fixed structure " carried in the claim 1, it is characterized in that: giving molded rod, it is configuration insulation sheet respectively symmetrically up and down, graphite flake and agalmatolite ring in the conductive steel lining papers is arranged.Their periphery is the agalmatolite piece.Graphite flake necessarily is placed between steel loop and the insulation sheet.

8, according to " the special process condition " carried in the claim 1, it is characterized in that: adopt the conditional operation that becomes power, transformation power when synthetic, that is: had a power failure one period blink before 1 minute in soak, and the preceding power that has a power failure is higher than the power after the power failure; And later stage pressure ratio pressure high ten in early stage is to tens of kilograms;

9, " through rational acid treatment " carried in the claim 1, it is characterized in that: when removing graphite, use earlier sulfur waste acid, nitric acid mixed solution (can add eo-acid in right amount) is handled and is removed a small amount of graphite with Xiization And, the back is eluriated with clear water and is removed graphite, handle with new sulfuric acid, nitric acid mixed solution again, realize removing fully graphite.

10, according to " feature of the present invention " carried in the claim 1, they have additivity, promptly do not adopt one of them technical measures, can influence but do not influence the synthetic effect of diamond at all.

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