GB/T 43349-2023Liming material - Determination of neutralizing value - Titrimetric methods (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document is equivalent to ISO 20978:2020 "Titration method for determination of neutralization value of calcareous materials". This document has made the following minimal editorial changes.

---In order to comply with my country's usage habits, the chemical formula of hydroxide ion is changed from "HO-" to "OH-";

---Revise the printing error and change "CaO" in the header of Table B 5 to "OH-".

1 Scope

This document describes a method for the determination of the neutralization value of calcareous materials with a P2O5 content of less than 3%.

Method A is applicable to all calcareous materials except silicate calcareous materials.

Note 1. Hard calcareous materials such as limestone and dolomite; soft calcareous materials such as chalk, marl and hydrated lime. Method B is suitable for all calcareous materials.

Neither method takes into account the potential neutralization value of calcareous materials containing more than 3% P2O5. In order to more accurately determine P2O5 containing more than Neutralization efficiency for 3% calcareous material samples, see EN 14984.

Note 2. The determination of P2O5 content can be based on ISO 6598 and ISO 7497. For more P2O5 content determination methods, see references [9] and [10].

Note 3. Carbonate reacts with H in the aqueous solution to generate H2O and CO2 to reduce the acidity of the aqueous solution. And orthophosphate reacts with H in aqueous solution It will not produce molecular products and will not reduce the acidity of the aqueous solution. Therefore, backtitration of this partial acid using a base will result in a neutralization value On the low side.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

ISO 3310-1 Technical requirements and inspection of test sieves Part 1. Test sieves with braided wire mesh (Testsieves-Technical Note: GB/T 6003.1-2022 Technical requirements and inspection of test sieves Part 1: Wire braided mesh test sieves (ISO 3310-1:2016, MOD) andtestmethods)

Note: GB/T 6682-2008 Specifications and test methods for water used in analytical laboratories (ISO 3696:1987, MOD) stances-Vocabulary)

Note: GB/T 6274-2016 Terminology for fertilizers and soil conditioners (ISO 8157:1984, NEQ)

ISO 14820-2 Sampling and sample preparation of fertilizers and calcareous materials Part 2. Sample preparation (Fertilizersandli- 3 Terms and definitions The terms and definitions defined in ISO 8157 apply to this document.

4 Method summary

The sample is dissolved in a certain amount of hydrochloric acid standard solution, and the excess acid is back-titrated with sodium hydroxide standard solution.

Note: For products containing iron, the iron must be pre-oxidized in method B.