The pelleting of micro-fine agricultural lime to treat soil acidity, using sodium alginate, lignosulphonate, and bentonite as binders
| dc.contributor.advisor | Goosen, N. J. | en_ZA |
| dc.contributor.advisor | Pott, Robert William M. | en_ZA |
| dc.contributor.author | Schwaeble, Claudia Francesca | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering. | en_ZA |
| dc.date.accessioned | 2021-03-08T11:15:32Z | |
| dc.date.accessioned | 2021-04-21T14:39:22Z | |
| dc.date.available | 2021-03-08T11:15:32Z | |
| dc.date.available | 2021-04-21T14:39:22Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MEng)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Limestone is often used to ameliorate soil acidity, as the release of carbonate ions neutralises acids in the soil. Agglomerated micro-fine limestone is an attractive alternative to powdered limestone for use in agriculture, mitigating product losses as a result of unfavourable weather conditions during and after conventional top-dress application. Binders, specifically sodium alginate, lignosulphonate and bentonite, were investigated in the agglomeration of micro-fine limestone. The effect that binder concentration had on agglomerate strength was investigated to determine whether the agglomerates were durable enough to withstand typical transport and handling processes. Agglomerates were produced in an inclined disc agglomerator, set to 45X. The significance of rotational speed, liquid addition, and binder concentration were assessed using CCD analyses, with the yield of agglomerates of 2-5.6 mm in diameter, as the response variable. Speed of rotation was insignificant in the 20-55 rpm range and was set to 37.5 rpm. The volumes of liquid added proved significant in maximising the yield, with sodium alginate, lignosulphonate, and bentonite requiring 20 m`, 18 m`, and 22 m` of liquid per 100 g of powdered constituents, respectively. To compare the effect that the binder concentration had on their physical properties, strength tests were carried out on agglomerates at concentrations of 1-7 g sodium alginate, 7.2-14.4 g lignosulphonate and 10-70 g bentonite, per kilogram. The results showed that sodium alginate performed significantly better in resisting breakage due to impact and compression. At significant concentrations for each binder type, they all produced agglomerates that performed acceptably in resisting abrasive wear. With the ability to absorb water, the agglomerates of bentonite included at > 40 g/kg resisted disintegration for longer than the other agglomerate types, when saturated in water. However, agglomerates containing sodium alginate and bentonite at 4 or 5 g/kg and 70 g/kg respectively, proved strong enough to withstand all stresses that may arise during transportation, storage and handling. Specific to South African soil, the Eksteen method was used to determine the amount of limestone required to ameliorate soil acidity in the soil used in this research. Agglomerates containing sodium alginate at 4 and 5 g/kg, lignosulphonate at 14.4 g/kg, and bentonite at 40 and 70 g/kg were placed on the surface of 25 cm deep soil columns, in masses corresponding to the limestone requirement of 0.01114 g/cm3. The soil columns were exposed to a 14-week rainfall simulation, thereafter the movement of the limestone through the soil columns was investigated using XRF analysis of soil samples from different depths. These results, along with pH and electrical conductivity tests, showed that the limestone did not successfully penetrate or ameliorate soil acidity below 2.5 cm of the soil columns. An inclined disc agglomerator was therefore successfully designed, manufactured, and commissioned for the agglomeration of limestone. This research successfully demonstrated that sodium alginate and bentonite are feasible binders for limestone, producing agglomerates with physical properties appropriate for commercial use. It was also demonstrated that the agglomerates would disintegrate when exposed to natural weathering, but would require significantly more time to ameliorate soil acidity at depths deeper than the surface. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Kalkklip word gereeld gebruik om grondsuurheid te verbeter, omdat die vrylating van karbonaatione sure in die grond neutraliseer. Geaglomereerde mikrofyn kalkklip is ’n aanloklike alternatief vir gepoeierde kalkklip vir gebruik in landbou, waar produkverlies as gevolg van ongunstige weerkondisies gedurende en na konvensionele bobemesting, verminder word. Verbinders, spesifiek natriumalginaat, lignosulfonaat, en bentoniet, is ondersoek in die agglomerasie van mikrofyn kalkklip. Die effek wat verbinderkonsentrasie op agglomeraatkrag gehad het, is ondersoek om te bepaal of die agglomerate sterk genoeg was om tipiese vervoer- en hanteringsprosesse te kan weerstaan. Agglomerate is geproduseer in ’n skuins skyf agglomerator, op 45X gestel. Die beduidendheid van rotasiespoed, vloeistof byvoeging en verbinderkonsentrasie is geassesseer deur CCD-analise te gebruik, met die opbrengs van agglomerate van 2-5.6 mm in deursnit as die responsveranderlike. Spoed van rotasie was onbeduidend in die 20-50 rpm bestek en is gestel na 37.5 rpm. Die volume vloeistof bygevoeg was beduidend om die opbrengs te maksimeer, met natriumalginaat, lignosulfonaat en bentoniet wat 20 m`, 18 m` en 22 m` van vloeistof per 100 g gepoeierde bestanddele, onderskeidelik, vereis het. Om die effek wat die verbinderkonsentrasie op hul fisiese eienskappe het te vergelyk, is kragtoetse uitgevoer op agglomerate by konsentrasie van 1-7 g natriumalginaat, 7.2-14.4 g lignosulfonaat en 10- 70 g bentoniet, per kilogram. Die resultate het getoon dat natriumalginaat beduidend beter presteer het om afbreking te weerstaan as gevolg van impak en kompressie. By beduidende konsentrasie vir elke tipe verbinder, het hul almal agglomerate geproduseer wat aanvaarbaar presteer het om afskurende verwering te weerstaan. Met die vermoë om water te absorbeer, het die agglomerate wat bentoniet ingesluit het by > 40 g/kg disintegrasie vir langer as die ander agglomerate weerstaan, wanneer in water deurweek is. Agglomerate wat natriumalginaat en bentoniet by 4 en 5 g/kg en 70 g/kg, onderskeidelik, bevat het, was sterk genoeg om alle spannings wat kon voorkom gedurende vervoer, bewaring en hantering, te weerstaan. Spesifiek tot Suid-Afrikaanse grond, was die Eksteenmetode gebruik om die hoeveelheid kalkklip te bepaal wat benodig word om grondsuurheid in die grond gebruik in hierdie navorsing, te verbeter. Agglomerate wat natriumalginaat by 4 en 5 g/kg, lignosulfonaat by 14.4 g/kg, en bentoniet by 40 en 70 g/kg bevat, was op die oppervlak geplaas van 25 cm-diep grondkolomme, in gewigte wat met die kalkklip vereistes van 0.01114 g/cm3 ooreenstem. Die grondkolomme is aan ’n 14-week reënval simulasie blootgestel, en die beweging van die kalkklip deur die grondkolomme is daarna ondersoek deur XRF-analise van grondsteekproewe van verskillende dieptes te gebruik. Die resultate, saam met pH- en elektriese geleidingsvermoëtoetse, het getoon dat die kalkklip nie suksesvol kon penetreer of grondsuurheid onder 2.5 cm van die grondkolomme kon verbeter nie. ’n Skuins skyf agglomerator is daarom suksesvol ontwerp, vervaardig en in gebruik geneem vir die agglomerasie van kalkklip. Hierdie navorsing het suksesvol gedemonstreer dat natriumalginaat en bentoniet uitvoerbare verbinders vir kalkklip is, wat agglomerate met fisiese eienskappe gepas vir kommersiële gebruik, produseer. Dit is ook getoon dat die agglomerate sou disintegreer wanneer dit blootgestel word aan natuurlike verwering, maar beduidend meer tyd vereis om grondsuurheid by dieptes dieper as die oppervlak te versag. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xviii, 148 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/110080 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Agglomeration | en_ZA |
| dc.subject | Agricultural lime -- Agglomeration | en_ZA |
| dc.subject | Sodium alginate | en_ZA |
| dc.subject | Bentonite | en_ZA |
| dc.subject | Lignosulphonate | en_ZA |
| dc.subject | Soil acidity | en_ZA |
| dc.subject | Pelletizing | en_ZA |
| dc.subject | Liming of soils | en_ZA |
| dc.subject | Binders (Materials) | en_ZA |
| dc.subject | UCTD | |
| dc.title | The pelleting of micro-fine agricultural lime to treat soil acidity, using sodium alginate, lignosulphonate, and bentonite as binders | en_ZA |
| dc.type | Thesis | en_ZA |