9 replies to this topic

[hamadzzz]

|Dear friends ,

i am HGA process engineer . currently I am working beneficiation plant .The plant is in its feed phase .i want to know more about phosphate beneficiation plant process .starting from crushing ,comminution ,floatation cell up to storage stage .


it is my pleasure to receive your comments and reply especially from who working in the same field or from people they can direct me to right place to get this type of information .

Thanks all
HGA
anazihg@gmail.com

[khurram]

dear friend , i'm also working for the same plant ....please help me with your experience....


thanks....
chem.eengineer@gmail.com

[kkala]

Having worked in a NPK fertilizer plant for almost 6 years, we used several phosphate types for 30% P2O5 phosphoric acid production (Taiba, Gafsa, Maroc) , without any thought of beneficiation ever. We only installed a Raymond mill for phosphate fine grinding, which was economically justified by the increase in P2O5 recovery in the reactor (say from 96% to 96.3%, in 1978). But the feed of ground and screened phosphate should be well mixed before the phosphoric acid reactor. Gypsum was disposed of as a byproduct, yet later was accumulated within the factory (no place for disposal).
It is assumed that phosphate beneficiation in question occurs in the mine. Beneficiation process seems to be depending on the specific phosphate rock. E.g. http://www.efma.org/.../EFMABATPHO.pdf says: "Most phosphate ores have to be concentrated or beneficiated before they can be used or sold on the international phosphate market. Different techniques may be used at the beneficiation stage, to treat the same ore for removal of the gangue and associated impurities. This gives rise to further variations in the finished ore concentrate product. Phosphoric acid technology, having to rely on raw materials of great variety, has to readapt itself constantly."
I do not have knowledge on "phosphate beneficiation" , but googling this title will reveal rather usefull information, e.g. http://www1.fipr.sta...5256F790066A89A . Specific pilot tests may be required after a general knowledge on the subject. Removing sand and clay can be the first stage, then floatation is a way for further increase of P2O5. But floatation requires proper grinding in advance, see froth flotation at http://en.wikipedia....otation_process.

Edited by kkala, 28 August 2011 - 01:35 AM.

[DOXA]

Hi, I'm actually working in the beneficiation of phosphate ores in Bolivia, having some problems with the Al2O3 and Fe2O3 high content (about 3 and 6 % respectively), i like to share some experiences about the beneficiation of phosphate ores.
feel free to write me at fabianbenaventea@gmail.com

Grtz to all.

[DOXA]

Having worked in a NPK fertilizer plant for almost 6 years, we used several phosphate types for 30% P2O5 phosphoric acid production (Taiba, Gafsa, Maroc) , without any thought of beneficiation ever. We only installed a Raymond mill for phosphate fine grinding, which was economically justified by the increase in P2O5 recovery in the reactor (say from 96% to 96.3%, in 1978). But the feed of ground and screened phosphate should be well mixed before the phosphoric acid reactor. Gypsum was disposed of as a byproduct, yet later was accumulated within the factory (no place for disposal).
It is assumed that phosphate beneficiation in question occurs in the mine. Beneficiation process seems to be depending on the specific phosphate rock. E.g. http://www.efma.org/.../EFMABATPHO.pdf says: "Most phosphate ores have to be concentrated or beneficiated before they can be used or sold on the international phosphate market. Different techniques may be used at the beneficiation stage, to treat the same ore for removal of the gangue and associated impurities. This gives rise to further variations in the finished ore concentrate product. Phosphoric acid technology, having to rely on raw materials of great variety, has to readapt itself constantly."
I do not have knowledge on "phosphate beneficiation" , but googling this title will reveal rather usefull information, e.g. http://www1.fipr.sta...5256F790066A89A . Specific pilot tests may be required after a general knowledge on the subject. Removing sand and clay can be the first stage, then floatation is a way for further increase of P2O5. But floatation requires proper grinding in advance, see froth flotation at http://en.wikipedia....otation_process.

Hi, i like to know more about the plant design of a phosphoric acid plant, I hope you can share some info and maybe give me some tips to the structuration of my project (plant design of phosphoric acid plant production).
thanks in advance

[kkala]

Having worked in Fertilizers (Sep 1975 - Jun 1981), I spent three years in Operations of phosphoric fertilizers sector, including a phosphoric acid production plant. Produced phosphoric acid contained 30% - 32% P2O5 (w/w) and was used as is for N-P-K fertilizers. It was concentrated to almost 50% P2O5, if it was exported. Phosphates were from Africa (Taiba, Maroc, Gafsa) and arrived "ready for use". Total P2O5 loss was about 8%, that is P2O5 passing from phosphate to acid was about 92% (efficiency). We had installed a mill (Reymond type) to grind some types of phosphates and mix them with the rest on their way to reactor, but effectiveness of grinding had not been clear till 1981.
The dihydrate process was used (producing gypsum, CaSO4.2H2O), which was common at that time. A single reactor kept phosphate in suspension (liquid phase was H2SO4, H2O, H3PO4) through strong agitation through several vertical agitators mounted on reactor ceiling. Temperature of suspension was held constant at 78-80 oC to ensure dihydrate. Cooling was obtained by passing air from the surface of reactor liquid, which was scrubbed after that to remove HF / SiF4 and then went to atmosphere. Resulting slurry was transmitted to two rotary filters (each with numerous invertable buckets), where the slurry was "sucked" under vacuum to take the acid, then washed with water finally going to the reactor. Filter cake in the form of gypsum (probably 1.5 t / t Taiba) was rejected onto the ground near the factory, but further disposal was a problem. Trucks transported it to valleys (landfill material), but in about 2000 I was informed that it got stacked and accumulated near the factory because no disposal area could be found (the factory shut down in 2007).
The classical book was "Phosphoric Acid" Vol 1 and 2 by A V Slack (Marcel Dekker, 1968), that we had available in the factory. I think it is still useful, even though hemihydrate processes (producing CaSO4.1/2H2O) are common today. Slack also refers to the latter, probably less extensively than dihydrate. I assume you speak about a hemihydrate process. A good book on the subject (like Slack's) seems necessary to me for the Plant Design of a phosphoric acid unit. Cost estimates are not usually included in such technical books though. Main issue is to chose technology and reactor, at that time other local phosphoric acid (dihydrate) plants had four reactors in series, or flash cooling of slurry.
Involved in Operations, then in measuring gaseous effluents to prepare a bid for treatment, I had not enough time to go into design issues. However a good book can supply a lot of such data (that I could not recall or had no chance to observe). Placing "phosphoric acid" in the search engine of this forum, you will meet sporadic information that can be also useful. For instance data about phosphoric acid tanks (rubber lined), agitation, etc.
Besides it is noted that the reactor tank was internally covered with antiacid rubber and bricks. Agitators and pumps were made of stainless steel equivalent to 304L or 316L.

Edited by kkala, 22 June 2012 - 02:17 AM.

[thaqrhys]

Having worked in a NPK fertilizer plant for almost 6 years, we used several phosphate types for 30% P2O5 phosphoric acid production (Taiba, Gafsa, Maroc) , without any thought of beneficiation ever. We only installed a Raymond mill for phosphate fine grinding, which was economically justified by the increase in P2O5 recovery in the reactor (say from 96% to 96.3%, in 1978). But the feed of ground and screened phosphate should be well mixed before the phosphoric acid reactor. Gypsum was disposed of as a byproduct, yet later was accumulated within the factory (no place for disposal).
It is assumed that phosphate beneficiation in question occurs in the mine. Beneficiation process seems to be depending on the specific phosphate rock. E.g. http://www.efma.org/.../EFMABATPHO.pdf says: "Most phosphate ores have to be concentrated or beneficiated before they can be used or sold on the international phosphate market. Different techniques may be used at the beneficiation stage, to treat the same ore for removal of the gangue and associated impurities. This gives rise to further variations in the finished ore concentrate product. Phosphoric acid technology, having to rely on raw materials of great variety, has to readapt itself constantly."
I do not have knowledge on "phosphate beneficiation" , but googling this title will reveal rather usefull information, e.g. http://www1.fipr.sta...5256F790066A89A . Specific pilot tests may be required after a general knowledge on the subject. Removing sand and clay can be the first stage, then floatation is a way for further increase of P2O5. But floatation requires proper grinding in advance, see froth flotation at http://en.wikipedia....otation_process.

Knowing your experience in NPK fertilizer plant and in phosphate rock processing. I would like to know about Processing phosphate rock to Red Phosphorus. Thank you.

[kkala]

Unfortunately, thaqrhys, I cannot be helpful. In mentioned fertilizer plant phosphates were treated with H2SO4 to produce H3PO4, according to Ca3(PO4)2 + 3 H2SO4 + 6 H2O --> 3 CaSO4. 2H2O + 2 H3PO4. Produced H3PO4 reacted with NH3 to give phosphoric fertilizers, sometimes mixed with K2O. Reduction to elemental phosphorus (http://en.wikipedia....#Red_phosphorus '> http://en.wikipedia....#Red_phosphorus ) did not take place and must be quite a different technology. I believe it does not occur in fertilizer plants (never heard of it).

[thaqrhys]

Thank you for your quick response, Kkala. I could understand your explanation. Anyway, could you maybe have other reference for knowing better the production process of red phosphorus ?

[kkala]

I am sorry not to have any referrence on the phosphorous production process, I have known red phosphorous from your post, by searcing the web. In the fertilizer plant we had not thought of this matter at all. Phosphorous in rock and fertilizers was in the form of P2O5.