GB/T 20616-2026Fireworks - Determination of bismuth content in pyrotechnic composition (English PDF)

1 Scope

This document describes a method for determining the bismuth content in fireworks and firecracker gunpowder.

This document applies to the determination of bismuth content in fireworks and firecracker gunpowder.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 601 Preparation of Standard Titration Solutions for Chemical Reagents

GB/T 6682 Specifications and test methods for water used in analytical laboratories

GB/T 8170 Rules for rounding off numerical values and the representation and determination of limiting values

GB/T 41644 Test Methods for Fireworks and Firecrackers

AQ4115 Technical Specification for Preventing Static Electricity Hazards in Fireworks and Firecrackers

3 Terms and Definitions

This document does not contain any terms or definitions that need to be defined.

4 Principles

After pretreatment, the sample was fully dissolved in nitric acid and filtered. The pH of the solution was adjusted, and a precipitant was added to remove bismuth ions and trimethylolpropionate from the solution.

Ferric ions were separated from other components, and the total amount of bismuth and iron content were determined by disodium ethylenediaminetetraacetate (EDTA) complexometric titration.

Measure the sample and then calculate the bismuth content. For iron determination, sulfosalicylic acid is used as an indicator, and EDTA standard titration solution is used at 60°C.

Titrate at 70°C until the solution changes from red to light yellow and remains so for 30 seconds. Xylenol orange is used as an indicator solution when determining the total iron and bismuth content, and chloride solution is used...

Titrate with zinc standard solution until the solution changes from yellow to orange.

5 Reaction Formula

The reaction formula is as follows.

Bi2O3 6H = 2Bi3 3H2O

Fe 4HNO3(dilute)=Fe(NO3)3 NO-> 2H2O

Cu2 + 2OH^- = Cu(OH)2->

Cu(OH)2 4NH3 = [Cu(NH3)4]2 2OH^-

Bi3H2Y2-=BiY-2H […]