Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 11.1.2.3 High exhaust gas volume flowsThe main pollutants emitted to air are NO x , SO 2 , HF and dust (see again Table 1.1). However,the assessment of emissions from various sources needs to take into account the actual emissionvolume flow, which can differ significantly from source to source. To give an impression, Table1.4 shows some examples for emission volume flows.Source Volume flow UnitPrilling, various productions90000 – 2000000 xOther finishing sections, various productions 92000 – 340000Tail gas from nitric acid plantsTail gas from sulphuric acid plants20000 – 300000 x25000 – 125000 xNm 3 /hourPhosphate rock digestion 8000 – 25000Den, crusher, and enclosed conveyor belt (SSP/TSP) 25000Vent from urea synthesis section 420x [154, TWG on LVIC-AAF, 2006]Table 1.4: Examples for emission volume flowsThe examples are taken from this document1.1.2.4 Large volume by-productsThe following large volume by-products are generated:• phosphogypsum from the production of H 3 PO 4• fluosilicic acid from scrubbing of exhaust gases containing HF or SiF 4 , relevant in allactivities which include phosphate rock digestion and the production of HF• anhydrite from the production of HF.For example, 4 – 5 tonnes of phosphogysum are generated per tonne P 2 O 5 manufactured in theproduction of H 3 PO 4 . Hence, if Europe’s production capacity (2.25 Mtonnes per year accordingto Table 5.1) for the wet process was fully used, about 9 – 11 Mtonnes per year ofphosphogypsum would be generated.All these large volume by-products show the potential for valorisation, but transport costs,contamination with impurities and the competition with, e.g. natural resources, restrict thesuccessful marketing. Hence, excess volumes are disposed of, e.g. by landfilling.Concerning disposal and valorisation of phosphogypsum, see Section 5.4.13.Concerning recovery and valorisation of fluosilicic acid, see Sections 5.4.7, 6.4.4 and 10.4.3.Concerning valorisation of anhydrite, see Section 6.4.3.4 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers