[global]

3 parts Ca3(PO4)2+ 10C

It was written in the 50's, if that matters.  Is it calcium phosphate mixed with 10 parts of carbon, or does the plus sign indicate that heat is involved?
I should probably mention that it was originally written as:
3 parts 3Ca(PO3)2 + 10C
but as discussed in another post, that can't be correct, as 3Ca(Po3)2 doesn't exist.
I think it's just mixed, but what do I know.

[AWK]

Ca₃(PO₄)₂ + C

It is probably about a very long known method of obtaining phosphorus. But in the equation of reaction, there are coefficients 2 and 10 respectively.

[Borek]

You really should look for some primer on reaction equations.

[global]

Ca₃(PO₄)₂ + C

It is probably about a very long known method of obtaining phosphorus. But in the equation of reaction, there are coefficients 2 and 10 respectively.

That's what others have said.  So the equation as written can signify simple mixing or using heat, is that correct?
I'm sorry, I'm ignorant, I don't know what you mean by "in the equation of reaction, there are coefficients 2 and 10 respectively."
I know there are various forms of phosphorus, some of which can spontaneously combust.  Which is why I have been reluctant to add heat.
Anyway, I put the equation 'Ca₃(PO₄)₂ + 10C" into the chemical reaction calculator at:
https://www.symbolab.com/solver/chemical-reaction-calculator
and the result was 24CaPO+10C
I don't understand that, you'd think some of the carbon would combine with the oxygen.  As you might have guessed, I'm not a chemist.
At some point I'm going to try this, with a small amount, although I'm tempted to just get an allotrope of phosphorus and see if that will work just as well.  I'll probably end up trying both.
Update: I probably put the equation in wrong, I didn't know how to input the sub's, for instance Ca sub 3.  The calculator at https://www.webqc.org/balance.php wouldn't even solve the equation.
Update 2: Maybe it's more right than wrong, I put in the suggested equation, Ca3(PO4)2+C into webqc.org/balance and got Ca3(PO4)2+C=CO+Ca3P2.
In addition, this is what it said under the equation line:
Balanced equation:
Ca3(PO4)2 + 8 C = 8 CO + Ca3P2
Reaction type: double replacement

So I think you must be correct, AWK, the point is to get phosphorus.  How do I know how much heat to apply?

[Borek]

Try to find some primer on what the reaction equation is and what symbols do mean. Right now you are just wasting time because you have no idea what you are doing and why what you are doing doesn't make sense.

[global]

Try to find some primer on what the reaction equation is and what symbols do mean. Right now you are just wasting time because you have no idea what you are doing and why what you are doing doesn't make sense.

That's why I'm here, to get help figuring things out.  Sorry if I wasted your time.

[Corribus]

global, it'd be helpful if you provided a little context about what you're trying to do, and what your reference source is. You don't have much chemical knowledge, that's fine, but without a few more details it's hard to offer help. I don't think Borek was complaining that you were waiting his time. He was pointing out that you are wasting your time because what you're doing doesn't make a lot of chemical sense.

[global]

global, it'd be helpful if you provided a little context about what you're trying to do, and what your reference source is. You don't have much chemical knowledge, that's fine, but without a few more details it's hard to offer help. I don't think Borek was complaining that you were waiting his time. He was pointing out that you are wasting your time because what you're doing doesn't make a lot of chemical sense.

My time isn't worth anything, so it would be difficult to waste it.  It's from a patent from the 1950's, which I won't get into now, but if you really want to know, you can find it.  There is not much more more info than what I gave.  I don't know if Ca3(PO4)2+ 10C automatically signifies a reaction to isolate the phosphorus, or a simple mixing of the ingredients, and I guess no one else does, either, but giving the context wouldn't clear anything up.  After thinking about it some more, if it's a reaction, the patent might have stated that.  Unfortunately, inventors often leave things out of their patents, to make the invention more difficult to produce.  I will just have to try both ways, and see what I get.  I was hesitant to do this because of the reactivity of phosphorus, but the amounts needed are so small that it can't be that dangerous.

Update: I just did a search for  Ca3(PO4)2+ 10C, and got this page:
https://answers.yahoo.com/question/index?qid=20090730222418AAdcGhO

Yahoo Answers is usually the worst place in the universe to get an answer to anything, but the replies to the original question told me that to isolate phosphorus from Ca3(PO4)2 requires the addition of 6SiO2.  Which leads me to believe that the original equation, Ca3(PO4)2+ 10C, may be a simple mixing, and not a reaction to isolate the phosphorus.

[AWK]

The addition of silica to reduce phosphate with carbon optimizes the technological process saving the amount of energy needed. Without this addition, a temperature of about 500°C higher is needed, and the resulting by-products reduce the yield of the reaction. But you can still get traces of elemental phosphorus.

Patents are not written for followers to easily reproduce the process, but to reserve their own interests, and are usually understood by scientists familiar with the issue.