Standard No.:	GB/T 4699.8-2025
English Name:	Ferrochromium, silicochromium, nitrogen-bearing ferrochromium and high nitrogen ferrochromium—Determination of silicon content—Silicomolybdenum blue spectrophotometric method, silicon potassium fluoride titrimetric method and perchloric acid dehydration gravimetric method
Chinese Name:	铬铁、硅铬合金、氮化铬铁和高氮铬铁 硅含量的测定 硅钼蓝分光光度法、氟硅酸钾滴定法和高氯酸脱水重量法
Chinese Classification:	H11    Steel and iron alloy analysis method
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR; SAC
Issued on:	2025-8-29
Implemented on:	2026-3-1
Status:	to be valid
Superseding:	GB/T 5687.2-2007 Ferrochromium silicochromium and nitrogen-bearing ferrochromium—Determination of silicon content—The perchloric acid dehydration gravimetric method
Target Language:	English
File Format:	PDF
Word Count:	8500 words
Translation Price(USD):	255.0
Delivery:	via email in 1~3 business day

GB/T 4699.8-2025 Ferrochromium, silicochromium, nitrogen-bearing ferrochromium and high nitrogen ferrochromium—Determination of silicon content—Silicomolybdenum blue spectrophotometric method, silicon potassium fluoride titrimetric method and perchloric acid dehydration gravimetric method English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing thorugh draft translation, self-check, revision and varification) will be delivered upon being ordered. ICS 77.100 CCS H11 People's Republic of China National Standard GB/T 4699.8-2025 Replaces GB/T 5687.2-2007 Ferrochromium, Silicochromium, Nitrogen-bearing Ferrochromium and High Nitrogen Ferrochromium — Determination of Silicon Content — Silicomolybdenum Blue Spectrophotometric Method, Silicon Potassium Fluoride Titrimetric Method and Perchloric Acid Dehydration Gravimetric Method Issued: 2025-08-29 Implemented: 2026-03-01 Issued by: State Administration for Market Regulation Standardization Administration of China ‌Contents‌ Foreword 1 Scope 2 Normative References 3 Terms and Definitions 4 Method 1: Silicomolybdenum Blue Spectrophotometric Method 5 Method 2: Silicon Potassium Fluoride Titrimetric Method 6 Method 3: Perchloric Acid Dehydration Gravimetric Method 7 Test Report ‌Warning‌ — Users of this document should have formal laboratory working experience. This document does not address all possible safety issues. Users are responsible for taking appropriate safety and health measures and ensuring compliance with national regulations. 1 Scope This document specifies three methods for determining silicon content in ferrochromium, silicochromium, nitrogen-bearing ferrochromium and high nitrogen ferrochromium: Method 1: Silicomolybdenum blue spectrophotometric method (applicable to ferrochromium, nitrogen-bearing ferrochromium and high nitrogen ferrochromium with silicon content 0.10%-6.00% by mass) Method 2: Silicon potassium fluoride titrimetric method (applicable to silicochromium with silicon content 30.00%-50.00% by mass) Method 3: Perchloric acid dehydration gravimetric method (applicable to all specified alloys with silicon content 0.10%-60.00% by mass) 2 Normative References The following documents are indispensable for the application of this standard: GB/T 4010 Sampling and preparation of samples for chemical analysis of ferroalloys GB/T 6682 Water for analytical laboratory use — Specification and test methods GB/T 8170 Rules for rounding off numerical values and expression of limiting values GB/T 12806 Laboratory glassware — One-mark volumetric flasks GB/T 12807 Laboratory glassware — Graduated pipettes GB/T 12808 Laboratory glassware — One-mark pipettes 3 Terms and Definitions This document contains no terms requiring definition. 4 Method 1: Silicomolybdenum Blue Spectrophotometric Method 4.1 Principle The sample is dissolved in dilute hydrochloric acid and hydrogen peroxide or alkali fusion. Ammonium molybdate reacts with silicon to form silicomolybdic heteropoly acid. Oxalic acid eliminates interference from phosphorus and arsenic. The silicomolybdenum yellow is reduced to silicomolybdenum blue by ammonium ferrous sulfate, and the absorbance is measured at 680 nm wavelength using a spectrophotometer to calculate silicon content.