Dihydrogen wolframate

Manufacture

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Manufacture of tungstic acid based catalysts

Manufacture

Contributing activity / technique for the environment

Name of activity / technique:

Manufacture of tungstic acid based catalysts

Environmental release category (ERC):

ERC1: Manufacture of the substance

Contributing activity / technique for workers

Contributing activity / technique for workers 1

Name of activity / technique:

Step 1: Raw material delivery and handling

Process category (PROC):

PROC 2: Chemical production or refinery in closed continuous process with occasional controlled exposure or processes with equivalent containment conditions

PROC 4: Chemical production where opportunity for exposure arises

PROC 8a: Transfer of substance or mixture (charging and discharging) at non-dedicated facilities

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 2

Name of activity / technique:

Step 2: Catalyst production

Process category (PROC):

PROC 1: Chemical production or refinery in closed process without likelihood of exposure or processes with equivalent containment conditions

PROC 2: Chemical production or refinery in closed continuous process with occasional controlled exposure or processes with equivalent containment conditions

PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions

PROC 4: Chemical production where opportunity for exposure arises

PROC 14: Tabletting, compression, extrusion, pelletisation, granulation

PROC 27b: Production of metal powders (wet processes)

Contributing activity / technique for workers 3

Name of activity / technique:

Step 3: Catalyst packaging

Process category (PROC):

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 4

Name of activity / technique:

Step 4: Maintenance and cleaning

Process category (PROC):

PROC 2: Chemical production or refinery in closed continuous process with occasional controlled exposure or processes with equivalent containment conditions

PROC28: Manual maintenance (cleaning and repair) of machinery

Contributing activity / technique for workers 5

Name of activity / technique:

Step 5: catalyst storage

Process category (PROC):

PROC 2: Chemical production or refinery in closed continuous process with occasional controlled exposure or processes with equivalent containment conditions

PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions

Related assessment:

use assessed in a joint CSR

Manufacture of tungstic acid powder

Manufacture

Contributing activity / technique for the environment

Name of activity / technique:

Manufacture of tungstic acid powder

Environmental release category (ERC):

ERC1: Manufacture of the substance

Contributing activity / technique for workers

Contributing activity / technique for workers 1

Name of activity / technique:

Step 1: Raw material handling: Ammonium paratungstate (APT) powder is received and stored in sealed containers. APT is transferred to a mill.

Process category (PROC):

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 2

Name of activity / technique:

Step 2: Milling: ammonium paratungstate (APT) is ground in a mill

Process category (PROC):

PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions

Contributing activity / technique for workers 3

Name of activity / technique:

Step 3: Filling of APT: Milled ammonium paratungstate is filled into drums

Process category (PROC):

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 4

Name of activity / technique:

Step 4: Preparing the reaction solution: The ammonium paratungstate is decanted into a stirred reactor by an automated drum decanting system and suspended with water. The nitric acid is metered continuously into the reactor (directly pumped) by a closed, automated feed system. The result of this process is a tungstic acid suspension

Process category (PROC):

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 5

Name of activity / technique:

Step 5: Precipitation step: The suspension of tungstic acid is pumped into another vessel and stirred until precipitation / crystallisation has finished

Process category (PROC):

PROC 3: Manufacture or formulation in the chemical industry in closed batch processes with occasional controlled exposure or processes with equivalent containment conditions

Contributing activity / technique for workers 6

Name of activity / technique:

Step 6: Filtration of tungstic acid: The suspension of tungstic acid is filtered by a band filter and washed

Process category (PROC):

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 7

Name of activity / technique:

Step 7: Drying of tungstic acid: The press cake of tungstic acid is transferred to a revolving silo and subsequently relayed to a spray dryer where it is dried. The dry substance is transferred to a silo

Process category (PROC):

PROC 8b: Transfer of substance or mixture (charging and discharging) at dedicated facilities

Contributing activity / technique for workers 8

Name of activity / technique:

Step 8: Packaging of tungstic acid: The dried tungstic acid is filled into containers from the silo

Process category (PROC):

PROC 26: Handling of solid inorganic substances at ambient temperature

Contributing activity / technique for workers 9

Name of activity / technique:

Step 9: Mixing and packaging of tungstic acid: 3 – 4 containers of tungstic acid are homogenised in a mixer and subsequently packaged

Process category (PROC):

PROC 26: Handling of solid inorganic substances at ambient temperature

Contributing activity / technique for workers 10

Name of activity / technique:

Step 10: Quality control: Finished tungstic acid powder is sampled for analysis

Process category (PROC):

PROC 15: Use as laboratory reagent

Contributing activity / technique for workers 11

Name of activity / technique:

Step 11: Maintenance and cleaning: Various maintenance and cleaning operations inside and outside the equipment

Process category (PROC):

PROC28: Manual maintenance (cleaning and repair) of machinery

Related assessment:

use assessed in a joint CSR