Standard No.:	GB/T 15057.7-1994
Chinese Name:	化工用石灰石中氧化铝含量的测定 铬天青S分光光度法
English Name:	Limestone for chemical industry- Determination of aluminium oxide content- Chromazurol S spectrophotometric method
Professional Classification:	D53 Building material raw material ore
Professional Classification:	GB National Standard
ICS Classification:	73.080
Issued by:
Issued on:	1994-05-05
Implemented on:	1995-02-01
Status:	VALID
Language:	English
File Format:	PDF
Word Count:	1500 words
Price(USD):	45 (USD)
Delivery:	via email in 1-3 business day

1 Subject Content and Application Scope

This standard specifies the determination of aluminium oxide content by chromazurol S spectrophotometric method.

This standard is applicable to the determination of aluminium oxide content in limestone products for chemical industry and the determination range is 0.01%~1%.

2 Normative References

GB 6682 Water for Analytical Laboratory Use - Specification and Test Methods

GB/T 9721 Chemical Reagent - General Rules for the Molecular Absorption Spectrophotometry (Ultraviolet and Visible)

3 Method Summary

Melt the specimen with mixed flux of sodium carbonate - boric acid, leach with hydrochloric acid, mask iron with ascorbic acid and mask titanium with benzoglycolic acid; in the buffer system of acetic acid - sodium acetate, aluminium reacts with chromazurol S and surface active agent and generates fuchsia ternary complex; then, measure the absorbance at spectrophotometer wavelength of 560mn.

4 Reagents and Solutions

Water used in this standard shall conform to the specification of Grade 3 water specified in GB 6682; unless otherwise specified, the adopted reagents refer to analytical reagents.

4.1 Mixed flux: take two portions of anhydrous sodium carbonate (GB 639) and one portion of boric acid (GB 628), porphyrize them and mix well.

4.2 Sodium hydroxide (GB 629) solution: 200g/L, stored in plastic bottle.

4.3 Sodium hydroxide solution: 50g/L, stored in plastic bottle.

4.4 Hydrochloric acid (GB 622) solution: 1+1.