A system for combined production of yellow phosphorous and syngas is disclosed. The air separation unit, the pulverized coal preparation unit and the mineral aggregate forming unit are respectively connected to a gas inlet and a top feeding port of the phosphorus coal gasifier; phosphorus-containing syngas obtained from phosphorus coal gasifier is connected to a gas inlet of the separating washing unit through an outlet of the phosphorous coal gasifier; Yellow phosphorus products and crude syngas are respectively output from the output port of the separating washing unit; and then the crude syngas is purified to obtain refined syngas. A slag discharge port at the bottom of the phosphorus coal gasifier is connected to an input port of a slag cold quenching unit. The system can improve the available energy of yellow phosphorous production, the production capacity of yellow phosphorus and the yield of syngas, and reduce CO.sub.2 emission.

Disclosed is a method for recovering phosphorus from sludge rich in chemical phosphorus precipitates using a high-protein biomass waste, comprising introducing the sludge rich in chemical phosphorus precipitates into an anaerobic fermenter, adding a certain amount of a high-protein biomass by-product, sealing the fermenter and fermenting for 4-7 days. The method can effectively increase the phosphorus release efficiency from the sludge, and also generate volatile short-chain fatty acids and ammonia nitrogen in high concentrations. After dewatering, phosphorus and part of ammonia nitrogen can be recovered in a form of high-purity struvite crystals only by addition of a magnesium salt and adjustment of pH to 7.5-9.0. The volatile short-chain fatty acids can be used as an economical carbon source. The method allows simultaneous utilization of two solid wastes to recover carbon, nitrogen and phosphorus resources, and can reduce the usage of chemical reagents, saving the treatment cost.

There is provided a multi-layered membrane comprising a top layer, a bottom layer, and a spacer layer; wherein said spacer layer is interposed between said top layer and said bottom layer; wherein said top layer, said bottom layer and said spacer layer are each independently composed of one or more selective layers, each selective layer comprising a 2D material; wherein said spacer layer comprises at least one channel for receiving a fluid; wherein said bottom layer comprises a hole with an area in the range of 1 μm.sup.2 to 1 mm.sup.2; and wherein said hole is capable of being in fluid communication with said at least one channels of said spacer layer.

There is also provided a method to synthesize the top layer of a multi-layered membrane as disclosed herein, methods for separating a plurality of ions or molecules in a fluid stream, a device comprising a multi-layered membrane as disclosed herein, and use of the method or the device as disclosed herein in osmotic power generation.

A composition of matter having the following chemical structure: $.Math.H_x{O}_{\frac{\left(x-1\right)}{2}}.Math.Z_y$
wherein x is
and odd integer ≥3;
y is an integer between 1 and 20; and
Z is one of a monoatomic ion from Groups 14 through 17 having a charge value between −1 and −3 or a polyatomic ion having a charge between −1 and −3.

A composition of matter having the following chemical structure: $.Math.H_x{O}_{\frac{\left(x-1\right)}{2}}.Math.Z_y$
wherein x is
and odd integer ≥3;
y is an integer between 1 and 20; and
Z is one of a monoatomic ion from Groups 14 through 17 having a charge value between −1 and −3 or a polyatomic ion having a charge between −1 and −3.

A process for separating heavy metals from a phosphoric starting material includes, in a step (i), heating the starting material to a temperature between 700 and 1,100° C. in a first reactor and withdrawing combustion gas. In a step (ii), the heated starting material at the temperature between 700 and 1,100° C. is transferred to a second reactor, chlorides of alkaline and alkaline earth metals are added and process gas is withdrawn.

A reagent system for treating heavy metal-contaminated materials is provided and includes an oxidizer, a soluble phosphate, and an alkaline hydroxide source, such as a caustic soda or lime. A method of treating mine waste bearing one or more heavy metals is also provided and includes the step of admixing a reagent system with heavy metal-containing material to preferentially reduce the leachability of heavy metals and form precipitates and complexes of low metal solubility that remain stable within the host solid matrix for long durations in acidic and abrasive conditions.

A reagent system for treating heavy metal-contaminated materials is provided and includes an oxidizer, a soluble phosphate, and an alkaline hydroxide source, such as a caustic soda or lime. A method of treating mine waste bearing one or more heavy metals is also provided and includes the step of admixing a reagent system with heavy metal-containing material to preferentially reduce the leachability of heavy metals and form precipitates and complexes of low metal solubility that remain stable within the host solid matrix for long durations in acidic and abrasive conditions.

An aqueous solution containing 30 ppm or more of carbon dioxide is brought into contact with a steel-making slag to elute phosphorus and calcium contained in the steel-making slag into the aqueous solution. Subsequently, carbon dioxide is removed from the aqueous solution to precipitate a mixture comprising a phosphorus compound and a calcium compound. In this manner, a mixture comprising a phosphorus compound and a calcium compound and containing phosphorus in an amount of 1% by mass or more in terms of phosphorus atom content can be produced.

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.