Fluosilicic acid (hexafluorosilicic acid), Fluosilicic acid, by-product (counted as 100 % H2SiF6)

Activity Phosphoric acid by the wet dihydrate process (merchant grade, from phosphate rock and sulfuric acid), RER: the inventory of 1 kilogram of its reference product, attributional, cut-off.

Calculation maturity: not assessed Design maturity: Concept (research)Not independently reviewedphosphoric-acid-1:phosphoric-acid-dihydrate:product:fluosilicic-acidPreliminaryReport a problem with this dataset

Research outputAn inventory from a research design at the design maturity its process states, not verified plant data: check its calculation maturity and review status before use. Background activities are referenced by name only; no background data is included. All caveats

What it is

Per 1 t of merchant-grade acid (53.97 wt% P2O5), gate-to-gate, from phosphate rock and sulfuric acid by the dihydrate process with concentration, EU conditions of the EFMA (2000) booklet and the LVIC-AAF BREF (2007). Feeds and gypsum from the stoichiometry of a model Moroccan rock with the sourced P2O5 efficiency; utilities from sourced ranges.

Reference product: 1 kilogram of Fluosilicic acid (hexafluorosilicic acid), Fluosilicic acid, by-product (counted as 100 % H2SiF6)
Chemical: fluosilicic-acid
CAS: 16961-83-4
Code: phosphoric-acid-1:phosphoric-acid-dihydrate:product:fluosilicic-acid
Dataset: phosphoric-acid-dihydrate version 0.1.0 · UUID 2b746c5d-8c3e-5a31-bd12-9fe37b926e94
Activity UUID: not available (the library assigns none; use the code)
Database: cheme-as-code-atlas-preview-a3c52e4 (version preview-a3c52e4)
Process: Phosphoric acid by the wet dihydrate process (merchant grade, from phosphate rock and sulfuric acid)
Geography: RER · background inputs with a site rule link at the user's site location (default DE)
Time period: 1996 · valid until 2011
Technology: wet process with sulfuric acid, dihydrate (DH) precipitation at 26 to 32 % P2O5 and 70 to 80 degC, vacuum flash cooling, belt or tilting-pan vacuum filtration, single-effect forced-circulation evaporation to merchant grade; continuous operation · level current
Boundary: gate-to-gate: rock grinding, attack and crystallisation, filtration, concentration, fluoride scrubbing and fluosilicic acid recovery; gypsum transport to the stack; steam and power from outside
Classification: ISIC Rev.4 2011 (taxonomy/families.yaml (ISIC Rev.4) of the process's families)
System model: attributional, cut-off (docs/system-model.md, methodology 1.1.0)
Allocation: mass, 1.3 % of the dataset to this product (rule deviation, from dataset)
No sourced prices, so the WBCSD price ratio of the acid and the fluosilicic acid cannot be computed; mass is the preliminary choice. The by-product carries about 1.3 % of the burdens by mass; economic allocation would give it less.
Rights: CC-BY-4.0

Exchanges per 1 kilogram of Fluosilicic acid (hexafluorosilicic acid), Fluosilicic acid, by-product (counted as 100 % H2SiF6)

As exported: allocated and scaled to the reference product. Provenance: 7 calculated, 4 given, 1 assumed. Pedigree scores (1 best, 5 worst): reliability, completeness, temporal correlation, geographical correlation, further technological correlation.

Preliminary5 exchanges are not yet linked to a background dataset. They count no burden, so the inventory is incomplete: do not read a result from it as complete.

Input	Amount	Unit	Provenance	Pedigree	Linked to
Phosphate rock, sedimentary (Moroccan type, 33.6 % P2O5 as modelled) feed:phosphate-rock stoichiometry with the efficiency eta. The rock is a model of the Khouribga analysis in EU JRC (2007) LVIC-AAF BREF (Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers) Table 5.2, p. 217 (33.4 % P2O5, 50.6 % CaO, 4.0 % F, 4.5 % CO2, 1.9 % SiO2): 3 Ca10(PO4)6F2 + 4 CaCO3 + CaF2 + 5 SiO2 gives 33.6 % P2O5, 51.6 % CaO, 4.0 % F, 4.6 % CO2; the other gangue (about 6 %) is counted as silica (ASSUMED). Morocco supplied 47.5 % of the EU's rock in 2004 (BREF 5.2.2.1.1). Compare 2.6 to 3.5 t/t P2O5 (benchmarks/phosphoric-acid.yaml)	1.669	kilogram	calculated	3 4 5 3 4	unlinked unlinked, no technosphere mapping: no mapping (chemical 'phosphate-rock'); add it to lci/mappings.yaml technosphere or to the process's lca/mappings.yaml exchanges
Sulfuric acid, 98.5 wt% feed:sulfuric-acid stoichiometry: one H2SO4 per Ca that leaves as gypsum (no free sulfate in the product, ASSUMED); counted as 98.5 wt% acid, the grade of sulfuric-acid-1. Compare 2.4 to 2.9 t H2SO4 per t P2O5 at one EU plant (EU JRC (2007) LVIC-AAF BREF (Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers) Table 5.5, p. 222)	1.369	kilogram	calculated	3 4 5 3 4	Atlas (pinned): Sulfuric acid from sulfur burning, double contact / double absorption (1000 t/d, 98.5 wt%) (Sulfuric acid 98.5 wt% to storage, GLO) compatible: grade the input names sulfuric-acid only; sulfuric-acid (Sulfuric acid 98.5 wt% to storage) is taken; unit kilogram; system model cutoff (one database); allocation shares (deviation); boundary plant gate (pinned): no distribution or losses; the consumer's dataset counts its delivery
Process water feed:water EFMA (2000) BAT Booklet No. 4, Production of Phosphoric Acid (Fertilizers Europe), 4.1, p. 29: 4 to 7 m3/t P2O5, scrubber water not included; midpoint, 1000 kg/m3	2.929	kilogram	given	3 4 5 3 3	market for water, deionised (water, deionised, RoW) in your background (default ecoinvent-3.11-cutoff)
Electricity feed:electricity EFMA (2000) BAT Booklet No. 4, Production of Phosphoric Acid (Fertilizers Europe), 4.1, pp. 29-30, upper end (with grinding) electricity	0.09585	kilowatt hour	given	3 4 5 3 3	market for electricity, medium voltage (electricity, medium voltage, DE, site location) in your background (default ecoinvent-3.11-cutoff)
Steam, by mass (concentration of the acid) feed:steam EFMA (2000) BAT Booklet No. 4, Production of Phosphoric Acid (Fertilizers Europe), 4.1, p. 30, upper end; pressure not stated. Where a sulfuric acid plant is on site its low-pressure exhaust steam is normally used (EFMA 4.1)	1.171	kilogram	given	3 4 5 3 4	Atlas: steam, saturated, 11 bar(a), per kg, as heat from steam (Atlas unit proxy) (steam, saturated, 11 bar(a), GLO)
Phosphogypsum to the stack: calcium sulfate dihydrate output:phosphogypsum Ca of the rock that leaves as CaSO4.2H2O; dry. Free moisture and slurry water are in output:wastewater. Disposal on land (stacking) is the EU practice (BREF 5.4.13). Compare 4 to 5 t gypsum per t P2O5 (BREF 5.2.2.5) for the four phosphogypsum outputs together	2.367	kilogram	calculated	3 4 5 3 4	unlinked unlinked, no technosphere mapping: no mapping (chemical 'phosphogypsum'); add it to lci/mappings.yaml technosphere or to the process's lca/mappings.yaml exchanges
Phosphogypsum to the stack: co-crystallised P2O5 (as CaHPO4.2H2O) output:gypsum-p2o5-loss the P2O5 not recovered (1 - eta); modelled as CaHPO4.2H2O (ASSUMED compound). The whole loss is put in the gypsum (ASSUMED), which gives 1.06 % P2O5 in the dry phosphogypsum; BREF 5.4.1, p. 227, gives about 0.75 % P2O5 in DH gypsum, so part of the real loss leaves by other routes (soluble P2O5 in the stack water, spills), which are not separated here	0.06795	kilogram	calculated	4 4 5 4 4	unlinked unlinked, no technosphere mapping: no mapping (no chemical slug or factor id); add it to lci/mappings.yaml technosphere or to the process's lca/mappings.yaml exchanges
Phosphogypsum to the stack: fluoride (as CaF2) output:gypsum-fluoride closes the fluorine balance: the rock's F less the acid, the recovered fluosilicic acid and the stack emission. BREF Table 5.9 puts 43 % of the F in DH gypsum and 43 % in vapours; the unrecovered vapour F goes to the condenser water, which a closed-loop plant returns to the stack (EFMA 4.3.2, 8.1.2), so it is counted here (69 %). CaF2 is an ASSUMED model compound (fluosilicates in practice)	0.09491	kilogram	calculated	4 4 5 4 4	unlinked unlinked, no technosphere mapping: no mapping (no chemical slug or factor id); add it to lci/mappings.yaml technosphere or to the process's lca/mappings.yaml exchanges
Phosphogypsum to the stack: silica and other insoluble gangue (as SiO2) output:gypsum-silica Si of the model rock not bound as fluosilicic acid; stands for silica and the other gangue (ASSUMED)	0.121	kilogram	calculated	4 4 5 4 4	unlinked unlinked, no technosphere mapping: no mapping (no chemical slug or factor id); add it to lci/mappings.yaml technosphere or to the process's lca/mappings.yaml exchanges
Water leaving the process (condensate, stack water, by-product water) output:wastewater ASSUMED closing term of the mass balance: process water and reaction water not bound in the product or the gypsum. Counted as effluent to treatment, conservatively: a closed-loop plant recycles its process and stack water and loses it by evaporation from the stack and cooling ponds (EFMA 8.1.2, AP-42 8.9.1)	2.239	kilogram	assumed	4 4 5 4 4	Atlas (plant): wastewater to treatment, per kg (Atlas unit proxy) (wastewater, by mass, GLO) compatible: grade the input names wastewater only; wastewater (Wastewater treated) is taken; unit kilogram; system model cutoff (one database); allocation mass (single-output); boundary plant gate of a site utility: no utility market yet (docs/markets.md)

Elementary flows

Flow	Direction	Compartment	Amount	Unit	Provenance	Pedigree
Hydrogen fluoride 8b7dc667-f04e-492c-a161-80b1482126b0	emission	air / non-urban air or from high stacks	2.243e-5	kilogram	given	4 4 5 4 4
Carbon dioxide, fossil aa7cac3a-3625-41d4-bc54-33e2cf11ec46	emission	air / non-urban air or from high stacks	0.07724	kilogram	calculated	3 4 5 3 4

Where these numbers come from: each exchange names its source above; the dataset is processes/phosphoric-acid-1/lca/datasets/phosphoric-acid-dihydrate.yaml in library version a3c52e4.

Used by

No other activity of this database links to it.

How good it is

Review: Not reviewed: no LCI review record yet
Data quality: not available
Mass and carbon closure: Not available: a hand-written dataset: no lca/manifest.json records its balance
Change report: Not available: this build has no change report against an earlier release.

KPI benchmark positions

KPI	Value	Reference range	Position
Fluoride to air (as F) per t of P2O5 produced	– g/t	2.3 to 2.3 g/t US EPA (1993, reformatted 1995) Compilation of Air Pollutant Emission Factors (AP-42), Fifth Edition, Volume I, Chapter 8: Inorganic Chemical Industry, Section 8.9 Phosphoric Acid (government)	not evaluated
Phosphogypsum generated per t of P2O5 produced	– t/t	4 to 5 t/t European Commission, JRC/EIPPCB (2007) Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers (LVIC-AAF BREF), adopted August 2007 (bref)	not evaluated
Electricity per t of P2O5 produced	– kWh/t	170 to 180 kWh/t European Commission, JRC/EIPPCB (2007) Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers (LVIC-AAF BREF), adopted August 2007 (bref)	not evaluated
Phosphate rock consumption per t of P2O5 produced	– t/t	2.6 to 3.5 t/t EFMA (2000) Best Available Techniques for Pollution Prevention and Control in the European Fertilizer Industry, Booklet No. 4 of 8: Production of Phosphoric Acid. European Fertilizer Manufacturers' Association (now Fertilizers Europe), Brussels (other)	not evaluated
Steam per t of P2O5 produced (concentrated)	– t/t	1.9 to 2.4 t/t European Commission, JRC/EIPPCB (2007) Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers (LVIC-AAF BREF), adopted August 2007 (bref)	not evaluated
Sulfuric acid (as 100 % H2SO4) per t of P2O5 produced	– t/t	2.4 to 2.9 t/t European Commission, JRC/EIPPCB (2007) Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers (LVIC-AAF BREF), adopted August 2007 (bref)	not evaluated

How to use it

Downloads

cheme-as-code-atlas-preview-a3c52e4.xlsx · bw2io ExcelImporter workbook (bw2io 0.9 Excel layout) · the whole database
code phosphoric-acid-1:phosphoric-acid-dihydrate:product:fluosilicic-acid
cheme-as-code-atlas-preview-a3c52e4-olca-jsonld.zip · openLCA JSON-LD (olca-schema) (2) · the whole database
process 2b746c5d-8c3e-5a31-bd12-9fe37b926e94 (processes/2b746c5d-8c3e-5a31-bd12-9fe37b926e94.json) · the dataset's unallocated multi-output process; this product's allocation factor is in it
cheme-as-code-atlas-preview-a3c52e4-multifunctional.json · Brightway 2.5 multifunctional database (JSON, for the multifunctional package) (cheme-as-code/lci-multifunctional/v1) · the whole database
code phosphoric-acid-1:phosphoric-acid-dihydrate · the dataset unallocated, with all its products; this product is its desired_code
cheme_as_code_lci-0.1.0-py3-none-any.whl · the installer

A file with this activity alone is not available: each file above is the whole database, and the line under it says how to find this activity there.

import bw2data as bd
from cheme_as_code_lci import install

bd.projects.set_current("my-project")   # holds your licensed background + biosphere3
install("cheme-as-code-atlas-preview-a3c52e4.xlsx", background="ecoinvent-3.11-cutoff", location="DE")
activity = bd.get_activity(("cheme-as-code-atlas-preview-a3c52e4", "phosphoric-acid-1:phosphoric-acid-dihydrate:product:fluosilicic-acid"))

While any exchange of the database has no mapping, install() writes nothing and only lists the unlinked exchanges. So the last line finds no activity until the gaps are mapped: the download section gives the ways to use the database now.

How to cite

Fluosilicic acid (hexafluorosilicic acid), Fluosilicic acid, by-product (counted as 100 % H2SiF6), from Phosphoric acid by the wet dihydrate process (merchant grade, from phosphate rock and sulfuric acid) (dataset phosphoric-acid-dihydrate 0.1.0), ChemE-as-Code Process Atlas LCI database preview-a3c52e4, activity phosphoric-acid-1:phosphoric-acid-dihydrate:product:fluosilicic-acid. Cite the Process Atlas paper (in preparation, 2026), by Artur M. Schweidtmann and Jana M. Weber, and the ChemE-as-Code Process Atlas LCI database version preview-a3c52e4.

DOI: none yet (the Process Atlas paper is in preparation)

For the data, cite the Process Atlas paper; for the platform that builds and checks it, the ChemE-as-Code paper.

Schweidtmann, A. M. & Weber, J. M. (2026, in preparation). Process Atlas: an open, git-native, reproducible library and life cycle inventory of chemical processes (working title).

BibTeX

@unpublished{schweidtmann_process_atlas,
  author = {Schweidtmann, Artur M. and Weber, Jana M.},
  title = {{Process Atlas: an open, git-native, reproducible library and life cycle inventory of chemical processes (working title)}},
  year = {2026},
  url = {https://atlas.cheme-as-code.org},
  note = {in preparation}
}

Schweidtmann, A. M. (2026). ChemE-as-Code: An Open-Source Platform for Agentic AI in Chemical Engineering. arXiv:2611.07947. https://doi.org/10.48550/arXiv.2611.07947

BibTeX

@misc{schweidtmann_cheme_as_code,
  author = {Schweidtmann, Artur M.},
  title = {{ChemE-as-Code: An Open-Source Platform for Agentic AI in Chemical Engineering}},
  year = {2026},
  eprint = {2611.07947},
  archivePrefix = {arXiv},
  doi = {10.48550/arXiv.2611.07947},
  url = {https://arxiv.org/abs/2611.07947}
}