Raw materials characterization for industrial lime manufacturing

1 Twin Shaft Regenerative (TSR) kiln. A: simplified scheme from European Commission (2010) [1], modified); B: a simplified scheme of Cimprogetti twin shaft regenerative kiln (2012)

2 Worldwide distribution of commercial limestones and dolomites analyzed by Cimprogetti S.p.A.

3 Classification of sedimentary carbonate rocks according to [1]. Symbols legend: 1: sample from Germany; 2: sample from South Africa; 3: sample from UAE; 4: sample from Malaysia

4 Carbonate rocks classification, based on calcite, dolomite, and clay minerals. Symbols legend: 1–4: pure limestones; 5: crystalline slightly calcitic dolostone

5 Microfacies analysis of carbonate rock samples. Symbols legend: PPL: plane-polarized light; XPL: cross-polarized light. a) Schematic profile of a carbonate platform. The presumed location of samples on the basis of typical depositional textures, and fossiliferous content is reported, as follows: 1: fore-reef open marine facies; 2: back-reef lagoonal facies; 3: shelf-edge oolite bars facies; 4: reef facies. b) Fossiliferous wackestone, sample 1 from Germany (PPL, 10X); c) Fossiliferous packstone, sample 2 from South Africa (PPL, 10X); d) Pisolitic-oolitic grainstone, sample 3 from UAE (PPL, 10X); e) Coralline boundstone, sample 4 from Malaysia (PPL, 10X); f) Diagenetic saccharine dolomite, sample 5 from Mexico (XPL, 3,5X). g) Calcitic marble with accessorial dolomite, quartz, and biotite, sample 6 from Congo (XPL, 3,5X)

6 Quicklime reactivity as a function of compositional (a) and textural parameters (b) [8]

7 Sticking tendency, namely overburning test, as a function of compositional (a) and textural parameters (b) [8]

8 Maximum slaking temperature vs. lime degradation test (a) and apparent density vs. maximum slaking temperature (b) [8]

Raw material influence on lime production

To meet the changing needs of different industrial sectors, various qualities of quicklime and hydrated lime are required. For this reason, an improved quality control in the calcination is necessary.

1 Introduction

Case studies reported in this paper provide a representative overview of the technical activity carried out worldwide by Cimprogetti S.p.A in the last ten years. Customers from all over the world always send commercial carbonate rock samples, namely “limestones” and “dolomites”, to evaluate their suitability for the calcination process in a Twin Shaft Regenerative kiln (TSR), subsequently designed, and installed, by the upper Italian company (Fig. 1).

Considering that different qualities of quicklime, and hydrated lime, have become needed to satisfy the new requests arising from...

TEXT Gabriele Vola, Geologist, Process & Laboratory Unit, Cimprogetti S.p.A., Dalmine/Italy
Luca Sarandrea, Technical Director, Cimprogetti S.p.A., Dalmine/Italy