Disclosed is an apparatus for preparing phosphoric acid from a fume exiting the kiln in a kiln phosphoric acid process, the apparatus comprises a hydration tower and an acid solution cyclical spraying system, a fume inlet of the fume exiting the kiln is disposed at a lower portion of the hydration tower, a fume outlet after hydration and absorption is disposed at the top, a spraying device is disposed in a cavity of the hydration tower above the fume inlet, a liquid inlet of the acid solution cyclical spraying system is disposed on a bottom of the hydration tower, a liquid outlet of the acid solution cyclical spraying system is connected to a liquid intake pipe of the spraying device. The present invention has the advantages of simple structure, reasonable layout, strong adaptability, high raw material utilization rate, reduced contaminant emissions, and high recovery rate of phosphoric acid etc.

A method for removal and recovery of phosphorus includes a precipitation step for precipitating phosphorus from a liquid stream comprising at most 30 mg of phosphorus per litre and at most than 50 mg of suspended solids per litre, using a precipitation agent, to form a precipitate, to form a precipitate; a first separation step for separating the precipitate from the liquid stream; a dissolution step for dissolving the precipitate in phosphoric acid to obtain a first solution; and a second separation step for separating the phosphoric acid and the precipitation agent.

A method of producing ammonium phosphates from at least one mineral containing phosphate and an element which is calcium, magnesium, iron, or aluminum. The method includes contacting the at least one mineral (or a combination of them) with a cation exchanger for a time and at a temperature sufficient to yield phosphoric acid from the mineral.

A method of producing phosphoric acid from at least one mineral containing phosphate and an element which is calcium, magnesium, iron, or aluminum. The method includes contacting the at least one mineral (or a combination of them) with a cation exchanger for a time and at a temperature sufficient to yield phosphoric acid from the mineral.

Disclosed is a raw material pre-treatment process system suitable for a kiln phosphoric acid process, comprising a carbonaceous reductant, a phosphate ore and a silica pre-treatment system which are independent from one another, outlets of the carbonaceous reductant, phosphate ore pre-treatment system and silica pre-treatment system are all connected to an inner pellet material mixing device via a first delivery device, and outlets of the carbonaceous reductant and the silica pre-treatment system are both additionally connected to a shell material mixing device via a second delivery device. Also disclosed is a raw material pre-treatment process suitable for a kiln phosphoric acid process, i.e. pre-treating carbonaceous reductant, phosphate ore and silica respectively, feeding the carbonaceous reductant powder, phosphate ore powder and silica powder into the inner ball material mixing device for pelletizing, and feeding the carbonaceous reductant and silica into the shell material mixing device for mixing.

A method of producing phosphoric acid from at least one mineral containing phosphate and an element which is calcium, magnesium, iron, or aluminum. The method includes contacting the at least one mineral (or a combination of them) with a cation exchanger for a time and at a temperature sufficient to yield phosphoric acid from the mineral.

Disclosed is a composite pellet used as a raw material in a kiln process for the production of phosphoric acid, which is of a core-shell structure with an inner ball encapsulated with a shell, the inner ball mainly consists of a inner ball material and a binding agent, and the shell mainly consists of a cladding material and a binding agent; the inner ball material mainly consists of a carbonaceous reductant powder, and phosphate ore powder and silica powder, the inner ball is combined with the shell through the binding agent to form the core-shell shaped structure. The preparation of the composite pellets comprises the steps of preparing the inner ball, preparing the cladding material, forming, drying and solidifying composite green pellets etc. The composite pellets prepared by the present invention have a smaller range of formulation fluctuation, more stable quality, higher strength and better performance.

A method for mass production of phosphoric acid with a rotary kiln, comprising the following steps: pretreating raw materials a carbonaceous reductant; preparing the pre-treated carbonaceous reductant powder; then evenly mixing the carbonaceous reductant powder and the silica powder to obtain a cladding material; mixing the cores and the cladding material for cladding treatment, drying and solidifying same to obtain composite pellets; sending the composite pellets into a rotary kiln for a reduction reaction; sending the high-temperature slag balls exiting the rotary kiln to a cooling device for comprehensive utilization; introducing the fume containing P.sub.2O.sub.5 and fluorine exiting the kiln into a hydration tower for absorbing phosphorus by hydration, then passing same through a phosphoric acid mist capturing tower and a mist removing and separating tower successively, and the fluorine-containing fume discharged from the mist removing and separating tower entering a subsequent fluorine recovery procedure.

A rotary kiln for reducing phosphate ore in kiln phosphoric acid process, comprising a kiln body, a kiln head box, a kiln tail box and a driving device for driving the rotation of the kiln body, wherein a fuel burner is provided at the kiln head, a feed pipe and an outlet flue connected to an external hydration tower are provided at the kiln tail box, the upper part of the kiln body is provided with no air pipe, the outlet flue is provided in the radius range of the kiln body with the axis of the rotary kiln as a center, and the fume conveying direction in the outlet flue is substantially parallel to the axis direction of the rotary kiln or has an included angle of less than 45 thereto. The rotary kiln can effectively mitigate the phenomenon of ring forming in the kiln tail of the rotary kiln.

A method of producing ammonium phosphates from at least one mineral containing phosphate and an element which is calcium, magnesium, iron, or aluminum. The method includes contacting the at least one mineral (or a combination of them) with a cation exchanger for a time and at a temperature sufficient to yield phosphoric acid from the mineral.