Why Not Solar Energy Cutting?

What is the type of basalt there?

I think you will need a big solar rays concentrator to get your energy sorted out. I also have the feeling that you might have plenty of troubles cutting rather than smelting.

There are other means to cut basalt more homogenous. I have been thinking of a high pressure abrasive water beam cutter. You could get the needed energy out of solar for this too.

The cutting residue, is probably also to use as a by- product ingredient for repairs, pasta, filler, cement.

I would like to see you cut a 1mm thick piece 1 square meter without breaking it!

O no, It's a matter of my bad english, not the plate should be 1 m.m thick!

The kerf!

No, your English is fine, I misread. Sorry.

And the size of the plate (or is it a block) will be?

It is still not clear to me yet.

1 m.m means?

m= meter

mm= millimeter = 1/1000 st of a meter

Once you will cut, you need a medium under pressure (several hundreds of psi -) of gas or liquid (air also considered as gas)

This medium needs to be able to travel through the whole gap, while it certainly also requires energy to produce the needed pressure to blow away the molten particles, but since it will also cool down the cut, you will need to calculate these losses also in your solar beam feed.

CORRECT! for this reason I gave up the idea of using concentrated solar energy- if it wasn't clear untill now.

3,600,000 Joules of work don over say an hour would be ~ 1KWH of which the sun is putting ~1,3 KWH of solar energy onto one square meter so I don't see this as being all that significant of concept to capture solar energy to such a thing.

Personally if it was me I would focus as much solar energy as I could using panels and lenses into as fine of beam as I could then use a jet of hot air to blow the molten material out of the cut sort of like a light based plasma cutter or a poor mans air jet laser cutter.

Well, 1 m.m thick kerf won't let us blow away the molten basalt, therefore it must be much wider kerf.Yes, I thought about the posibility of using hot air to blow away the molten basalt, but this would require again a much wider kerf, that would require more solar radiation...Anyway- my vision wasn't to demonstrate a green building technology, I thought about a viable technology that could compete present building technologies.Because the location of the cutting will be somewhere far from the electric grid,I would be really happy if the cutting machines were powered by solar energy but even then, I assume the owner of such a plant would prefere a generator for power supply !

Well being us modern humans and the countless not so modern generations who went before us have been working on ways to cut stone I suspect that at any point along the way the most practical and cost effective methods are what were used.

In most manufacturing processes the most energy efficient way is not always the most effective or practical way to get a job done.

Cost and practicality is why we use the methods we have now to do things the way we do just the same as our ancestors did in their times by using the most practical way they knew of even if there were methods that may have taken less energy.

Melting stone and blowing it away takes a lot of energy but pushing and pulling a fine band of steel or thin fabric covered in wet grit does not which is likely why we still use various methods of abrasive stone cutting that are still based the age old principles discovered countless centuries ago by some guy with some string, a rock, some wet sand and a bit too much free time on his hands one day.

Basalt has a fine grain structure that will produce a regular split if you subject it to enough pressure. Have you considered producing your building blocks in a hydraulic shear press? I do not know of any manufacturer producing a press for this application so you may have to design it from scratch. Massive pressures can be generated with a small hydraulic pump so power could be generated from a windmill or a modestly sized solar array. The blocks would not be as regular as cutting, but would key better to the mortar and provide a more aesthetic finish.

Have you had the boulders tested to confirm that they are basalt? Basaltic andesite, picrobasalt, trachy basalt, tephrite and basanite all look so similar to basalt that they are hard to distinguish, and for practical building purposes there would be no difference. Their chemical make up and how much resistance they exhibit to both cutting and splitting is very marked.

Basalt has a fine grain structure that will produce a regular split if you subject it to enough pressure. Have you considered producing your building blocks in a hydraulic shear press? I do not know of any manufacturer producing a press for this application so you may have to design it from scratch. Massive pressures can be generated with a small hydraulic pump so power could be generated from a windmill or a modestly sized solar array. The blocks would not be as regular as cutting, but would key better to the mortar and provide a more aesthetic finish.

I have seen workers who have, on a small scale, cut a kerf in a basalt rock (of unknown composition) with an abrasive wheel and then "cracked" the rock with a blow from a wide chisel and hammer and gotten quite a good surface. The chisel impulse blow apparently providing both shear and tension forces at the same time. I wonder if the original idea of the OP could be changed to simply provide a grove with less depth than he originally thought of but wider and a combination hot air and abrasive dust to clean the grove, then an impulse with a wedge shaped device by might not work. Just a thought with no special knowledge or experience.

I think the OP has

not enough info to share

Our company developed a prototype shear machine to test the mechanical strength of rocks. This has produced pretty accurate correlations in regard to shear strength and - surface, but only with calibrated sample (i.e. cylindrical or beam -like identical cut blocks - mostly produced with core drills and for the tests potted in epoxies)

The shear surface will be determined also with the contour of the bolder at the shear start line and will not be in the same plane. This has to do with the (reactive) dispersion of the initial force in fragmented mass patterns.

Also the inclusion of the bolder or surface contact area where it sits up is in play.

Even the basalt will need a "guided" weakening just as has been done with explosives in quarries to produce blocks. (drill tunneling)

But I still don't know if blocks, sheets or tiles he wants to produce.

And that is an essential given to think further

Given that the OP is on a kibbutz, I suspect that he is looking for a secondary revenue stream and has identified some boulders as a possible free raw material because they have to clear the boulders anyway in order to farm the land as their primary revenue stream. He thinks there is a market for building materials if he can shape the boulders into blocks. So he has come to CR4 to find a low cost, low energy, low labour method of turning boulders into building blocks, or sheets, or tiles, or anything else that will generate a revenue stream to offset the cost of clearing the land. OP please feel free to jump in if my supposition is incorrect. The other free raw material he has lots of is sunshine, so his first idea was to zap the boulders with with a home made death ray energy beam. He started by asking how to reduce the energy output (by making the narrowest possible cut) so that he does not have to build a full size death ray energy beam but rather an "Ouch that hurt a bit" ray. To this OP and to all other Ops. Please give us some context so that we can provide sensible answers to your questions. At present we are several answers into the second post and there is still confusion about what you are trying to achieve.

I am with you this far.If you go to the link he provides and the basalt he is talking about has a explorable fiber structure, he is probably maybe perhaps eventually trying to get these fibers to process into mesh or wire.

The 1 m.m is Chinese to me.

If fiber is the issue, I guess he needs to forget cutting at all, but e.g. compressing that the fibers show and will be collectable. There are numerous different types of basalt.

I think we are deadlocked by his secrecy? Those kibbutz guys seem to be interested in big harvests without planting or seeding.

You are absolutely [almost...] corrcet.

Yes, what drove me to try this solution were the ,fields and field margins where the boulders were pushed by a buldozer, and the fact that we have plenty of sun.

But what made me to share with you the ideas and the insights that followed the discussion and the intensive thinking, was that during the many,many times that I introduced an idea at cr4, very often the answer I received were with "understement" not really relevant, very often it became a forum for jokes, it is o.k for me. Here we are kind of community, people whom I can share some intereses of mine, the alternative for this kind of contact, is to go by bus [5 hours] to the Technion in Haifa and to meet there some scholars and experts , I use to do it, but the advantage of cr4, that within few hours, very often I get the information I need. [some times not!]

In my second post, I wanted to share with you my pride how I calculated carefully this situation of trying to indentify the obstacles to implement the already patented idea for rock cutting.

This event is teaching us another thing: Many people waste money for patenting an idea just because it seems to them that they were able to solve the technical challenge, but they didn't realize that good engineering requires economical feasibility as well!...

And as I mentioned the basalt fibers it was only because as I googled for informatiom about basalt, I learned about the basalt and basalt fibers, and their applications.

Thank you for sharing! I learned that basalt fiber has been around since the 1920's!

Use solar heat (maybe) to start breaking up the rock, but definitely use this for melting the rock in small batches (at first), for your die extrusions, but how will you find a die that can handle 2550 C or above, and how do you plan to drill tiny holes in it? Not really - mocking there - when this is molten, it can be drawn, cooled and spun to the 13-15 micrometer diameter range mentioned in the Wikipedia link you gave. You could use certain high melting metals (?Tantalum? ?Tungsten?) for the die, or maybe just use carbon or silicon carbide in an inert atmosphere. I see this sort of like lifting off nylon from a mix of the monomers where the liquids are in layers.

How much fiber of this kind do you want to produce? How big of a solar array furnace can you make? Remember that the larger the furnace, the more thermal inertia it has. Make smaller ones that are well insulated, and increase production by putting them in parallel.

Several years ago, the technology for drilling deep wells using lasers was announced. Then everything on the topic went dark (underground?). I expect the issue was keeping the focusing optic clean enough even with gas movement removing the ablation materials. This was hot enough to vaporize the rock and produce no molten matter, other than a slight "skinning" of the bore.

Why not use focused sonic or ultrasonic waves to scission the rock? Or even microwave energy? Other technique is use a wire saw, and silicon carbide dust.

I don't know that much about basalt, but I suspect that owing to the hexagonal crystal habit of most basalt, the best cleavage point is perdendicular to the crystal vertical axis. Have you considered Electrostriction? What are the stress/strain electrical characteristics of basalt?

If you can localize heating to produce shear stress, coupling a large amplitude standing wave into the rock might spilt it right at the stress point.