Potential beneficiation of readily available gold tailings and paper wastes:

development of a new building material

Tebogo Mashifana and Nastassia Sithole

University of Johannesburg, Department of Chemical Engineering Technology, P.O. Box 17011, Doornfontein

2088, South Africa.

Corresponding author: tmashifana@uj.ac.za

Abstract

Gold mine tailings (GMT) generated from gold mining processes are readily available in South

Africa. The generated GMT is disposed to the environment by land filling. This occupies

considerable land area, which subsequently result into environmental pollution. Numerous

industries uses paper for a number of application on daily basis and its generation is inevitable.

Unrecycled paper end up in the landfill, which has a negative impact on the environment, as it is

not degradable. This study investigated the blending of GMT and waste paper for the production

of building bricks (papercrete). The chemical composition of GMT in terms of elemental,

mineralogy and micrograph before and after paper stabilization was examined. Developed

composites were cured for 7, 14, 21, 28 days, and the unconfined compressive strength (UCS)

and absorption tests were conducted. The results obtained showed an improvement in both the

UCS and the water absorption of the bricks with the increment in curing period. The brick cured

for 28 days had the highest UCS of 7.76 MPa and the lowest water absorption of 80.43% when

compared to the bricks cured for 7,14 and 21 days. The developed papercrete was relatively light

in weight; however, they proved not to be suitable for outdoor walls and water logging areas due

to their high capability to absorb water.

Key words: Lightweight building bricks, gold mine tailings, papercrete, waste paper

1 Introduction

Environmental problems are firmly rooted at the center of all domains of development. The

development of processes from the applications of paper and the increasing demand of it and

the development in the mining industry subsequently leads to disposal and environmental

issues. The by-product of such developments leads to such wastes being found in landfills and

dumping sites causing pollution. One of the solutions to these problems is to exploit these

wastes in the production of value-added products. Since there is large demand of building

resources in the construction industry, especially in this decade due to the increase in

population which caused a prolonged shortage of building resources. It is highly recommended

to find innovative and creditable ways of converting such wastes to useful building and

construction materials. The emission of CO2 from construction sites due to the utilization of

cement is a worldwide issue. Papercrete is a recently developed construction material that

consists of re-pulped paper fiber with Portland cement or clay. It is recognized as an

environmentally friendly material due to its substantial recycled content. Patterson and McCain

discovered papercrete independently and is a mixture of cement, sand, and paper. It is a new

composite material using waste paper as a partial replacement of Portland cement and reducing

the quantity of cement required. The process also result into producing bricks that are

environmental friendly, as no raw materials is burned, when compared to the production of

cement (Shermale, 2017).

Papercrete reduces the amount of cement volume and when combined and cured, it produce a

product similar to concrete; however, it is very lightweight. Furthermore, the cost efficiency

gained by utilizing the sufficient supply of recycled paper reinforces the need for the research

of this alternative. The construction material density can be reduced through the addition of

and when utilized efficiently and the structural sound building can be maintained at a lower

cost. The basic constituents of papercrete are water and any kind of paper (newspaper,

cardboard, glossy magazine stock, advertising brochures, junk mail or any other type of paper)

with a binding material. The pulp fibers make up the bulk of the mix, resulting in a product that

is lightweight and strong and its strength attributed to the paper fibres (Shermale and Varma,

2015). The process of making papercrete includes soaking waste paper in water overnight so

that the paper fiber is softened and mixing the soaked paper using a stirrer until a homogeneous

pulp is obtained. The Portland cement, sand and water are added to the pulp and blended. The

mixture is discharged into casting molds, allowed to dry and cure. Papercrete has been used as

mortar in building walls through the addition of cement as a binder. More cement is required

to cover papercrete wall for the use of the mix as a plaster (Shermale, 2017). The major

advantage with the production of papercrete is that there is no excessive energy use in the

production of the bricks. There is no emission of harmful by-products and gases, which pollute

the environment. The only power needed in the process is for mixing and pumping of water. A

house made from papercrete is safer than one made from wood as it will not ignite or burn

(Shermale, 2017).

Although papercrete requires paper as the dominant raw material, it still requires the use of

cement, which plays an important role in the development of compressive strength. With the

rapidly increasing population in South Africa, the demand for housing increases and so is the

demand for the resources for building materials. The demand for cement is increasing which

consequently result into an increase in the carbon emissions, water pollution, and release of

heavy metals into the atmosphere. Accordingly, the environmental impacts of cement

production created a need for an alternative source of binding materials in order to sustain the

development. This work therefore proposes the use of the gold tailings as a replacement for

cement. In large volumes of materials considered as wastes or by-products are generated by

numerous industrial activities, most are disposed into sensitive environment and thus the need

for remediation (Mashifana et al. 2018)

The South African sector is the driving force behind the history and development of Africa and

ranks eighth in the world for the production of Gold with 139.9 tonnes of gold produced in

2017 (Writer, 2018). Approximately 165.6 tons of gold was produced during 2016 in South

Africa, 103.7 tons worth R60.6 billion was exported. South Africa is a developing country with

good infrastructure and enormous social and economic problems. The country is rich with

precious metals such gold and platinum, and base metals such as copper, nickel and aluminium.

With an abundance of such minerals, the exploitation of the minerals lead to the production of

a large volume of tailings. In 2016 there were 446 gold tailings reported to occupy at least 18

000 hectares across Johannesburg, (Breytenbach, 2016). Approximately 715 million tonnes

containing about 6.5 million ounces of gold are occupying the Sibanye’s tailings facility on the

West Rand, (Breytenbach, 2016). The development in the mining sector results in an increase

in tailings deposits annually. This does not only occupy an indefinite amount of land but result

into environmental pollution around the reservoir areas and high costs for the construction and

maintenance of tailings facilities, (Kunt et al., 2015). The comprehensive utilization of gold

mine tailings for the production of a value added product is important and can eliminate the

challenges related to environmental pollution.

There has been published information on the manufacturing of papercrete from cement and

sand; however, there is limited information on the development of papercrete with gold tailings

as a binding material. Studies are available with information on the engineering properties of

the material developed from other waste material as a binding material, partially or wholly

substituting cement. In 2006, Gorgis et al. studied the utilization of waste paper as a partial

addition by weight of cement. The researchers discovered that the mix gained its inherent

strength due to the presence of hydrogen bonds in the microstructure of paper. Additionally,

discovering that the compressive strength, splitting tensile strength, flexural strength, and

density decreased with increasing the percentage of waste paper addition.

1n 2017, Maheshwari carried a study on the evaluation of the strength, durability and structural

properties of fly ash based papercrete building bricks. The results showed that papercrete bricks

are relatively low cost, lightweight and more flexible. It also proved that papercrete is most

suitable for earthquake prone areas. The findings also showed that fly ash can replace up to

30% by mass of Portland cement, but can be used in higher dosages in certain applications. In

2014, Scinduja and Nathiya investigated the possible use of waste paper for producing a low-

cost and lightweight composite brick as a building material by using ground-granulated blast-

furnace slag mixed with quarry dust as one of the binding material besides cement. It was

concluded that the bricks were not suitable for water logging and external walls however are

ideal for the use in earthquake prone areas due to their lightweight and reduction of total dead

load. Although many efforts were extensively impressive and rewarding in applying

remarkable evolutions on the bricks industry as recycling various waste material. However,

they did not consider the urgent environmental threat and the intensive consumption of non-

renewable energy and associated emission of greenhouse gases such as carbon dioxide (CO2),

carbon monoxide (CO) and other pollutants considered to accelerate climate change. As a

vitrified or semi-vitrified ceramic, clay brick achieves a crystalline or semi-crystalline structure

due to the action of heat, it becomes hard and durable by firing in a kiln. The consequences of

the emission of the greenhouse gases from the traditional brick industry have substantially

polluted the surroundings with smog, global warming, acid rains, fog and climate change. The

hazardous impact of the conventional bricks manufacturing has been a major problem that

continuously distress different countries.

Toledo et.al. (2014) analyzed the crystalline structure and ceramic properties formed in the

process of firing of clay raw materials and pressed bricks. The firing cycle entailed the measure

of CO, CO2, NOX, and methane emissions. The result showed that there was 8600 ppm of CO2

emitted from the powder and 6500 ppm from the extruded sample. The emission of CO was

found to be 1100 ppm from the powder and 800 ppm from the brick. The gaseous pollutants

included fluorine 0.7- 4 ppm in stack gasses as well as SO2 and CO2. The H2 and Fl2 gases were

formed as the temperature approached 500-600 °C. The investigation also showed that the

energy expanded through the forming of the bricks, extraction and transportation was

approximately 4.5884 GJ/ton and around 6.5382 GJ/ton for finished clay brick. The energy

consumed through the production of sand lime brick approached 1.16498 GJ/ton. That is an

improvement as the total energy utilized for the production of one concrete block is

approximated at 2.91483GJ/tone. Koroneos and Dompros (2007) investigated the GHG

emission and energy consumption during the bricks production on a bricks plant in Greece.

The results obtained showed that the GHG emissions had approximately 220.68 kg of CO2,

2.23 kg of acidification emissions and 2.012Kg of winter smog emissions.

Michael et al. (2009) analysed the energy consumption and the GHG emission during the clay

brick production in the United States. According to his observation, the energy embodied for a

common fired clay brick was approximately 9.3 MJ/brick. The GHG emission per clay brick

fired using fossil fuel was approximately 0.6 kg of CO2 to the atmosphere whereas; one

ordinary concrete brick emits 0.3 kg of CO2. This study presents an inexpensive initiative that

focuses on reducing the landfilling of gold tailings and paper on the South African lands by

utilizing them in the production of cost effective and eco-friendly bricks. The aim of this study

was to investigate the probability of using domestic paper waste as a dominant raw material to

produce papercrete bricks with gold mine tailings as a binding material.

2. Experimental details

2.1 Materials

Waste paper was collected from schools, administration offices, planning, and libraries. The

paper shredded into small pieces by hand as shown in Figure 1. The gold tailings were obtained

from Barberton Gold Mine, South Africa. The tailings were dried in an oven before processing,

Figure 2. The dried tailings were sieved to acquire a homogenous batch with uniform particles.

The tailings was then characterized for mineralogy, elemental composition and using X-ray

diffraction (XRD), X-ray fluorescent (XRF), respectively.

Figure 1. Waste paper in small pieces before

processing.

Figure 2. GMT before processing.

2.2 Generation of Pulp for Papercrete Bricks

The pieces of paper were soaked in water overnight, and soon degraded into a paste like. After

that period, the papers were taken out from the bucket and shredded into smaller pieces and

then converted into pulp using a stirrer. The generated paper pulp is shown in Figure 3. The

paper pulp in Figure 4 had less residual water, hence it was good enough for mixing with the

gold tailings.

Figure 3. The immersion of paper in water. Figure 4. The generated paper pulp from shredded

paper.

2.3 Proportion of the mix design

Trial mix designs were prepared for workable mix while adding the gold tailings. Based on the

physical observation, the optimum mix proportion by weight was [1.222:1] paper-pulp: gold

tailings. Water to paper ratio was kept constant at 1:9. The weight of paper-pulp to gold that

used in all mixes were 137.5 g and 112.5 g, respectively. The specimen developed contained

the following mix designs: specimen A (45%GMT:55% pulp), specimen B

(40%GMT:60%pulp), specimen C (35%GMT:65%pulp), specimen D (30%GMT:70% pulp),

specimen E (25%GMT:75%pulp), specimen F (20%GMT: 80% pulp).

2.4 Characterization

2.4.1 X-ray fluorescence (XRF)

Sample preparation

10g of the dried sample and 3g of Sasol wax was weighed. The Sasol wax and dried material

was mixed using a pastel and mortar. The mixed sample was stored in the aluminium cup and

pressed to 25tons. The pressure was released after 2 minutes.

X-ray fluorescence (XRF) analysis.

The chemical analysis was carried out using wavelength dispersive X-ray fluorescence (XRF)

spectrometry (Axios, PANalytical, Netherlands) operated with a rhodium tube excitation

source.

2.4.2 X-ray diffraction (XRD) analysis

10 g of representative sample material was milled under alcohol to about 5-10 ~m (talcum

powder size) using a mortar and pestle. Subsequently, the sample was mounted in a sample

holder in such a way to minimise preferred orientation for XRD analysis.

2.5 Curing of papercrete bricks

The papercrete bricks were allowed to cure for 7, 14 21 and 28 days on the sun and then

subjected to geotechnical tests for UCS and water absorption and geochemical tests for

elemental, mineralogical, morphological and functional groups. The water absorption capacity

of the bricks cured at the period of 7, 14, 21 and 28 days was determined in accord with the

ASTM C642-13(2013).

3. Results and discussion

3.1 Characterization of gold tailings

3.1.1 Eelemental analysis of gold tailings

Table. 1 XRF analysis of gold tailings

Material SiO2 Al2O3 MgO CaO Fe2O3

Tailings Barberton 48.08 11.25 4.64 9.17 14.87

The Barberton gold mine tailings are mainly composed of were SiO2 (48.08%), Fe2O3 (14.87%)

and Al2O3 (11.25%) and CaO (9.17) as presented in Table 1. The highest proportion of silica

in the Barberton gold tailings is attributed to the Barberton rocks which contain about 50% of

quartz (silica) (Fall et al. 2010), confirming the high content of silica.

3.1.2 Mineralogical analysis of gold tailings

Figure 5. XRD analysis of gold tailings.

The gold mine tailings are mainly crystalline consisting of quartz, anorthite and magnetite. The

mineralogical analysis presented in Figure 5 agrees with the elemental composition presented

in Table 1. The high percentages of quartz were expected as stated by Vermeulen (2000) that

South African mines rocks are mostly quartzite and shales and the Barberton rocks consist

mainly of quartz.

3.1.3 Scanning Electron Microscope (SEM) analysis The materials were carbon coated and mounted onto SEM particle morphology determination.

3.2 Unconfined compressive strength and the developed specimen

The UCS test was performed on the specimen at different paper to gold tailings ratio, in order

to determine the optimum mix design with the highest UCS, Figure 6. The specimen were cured

for 28 days. Specimen A with the gold tailings content of 45% had the highest unconfined

compressive strength of 7.76 MPa. Specimen F with the gold tailings content of 20% by weight

had the lowest UCS of 3.08 MPa, showing a decrease of 60.31% in UCS when the gold tailings

content was decreased from 45% to 20%. It was also prominent that as the gold tailings ratio

decreased, the harder it was to blend the mix of the gold tailings and the paper-pulp.

Figure 6: Effect of gold tailings content on the

compressive strength at constant curing age of 28

days

Figure 7. (a) The brick from specimen D after de-

moulding (b) Surface of brick of specimen E after

de-moulding (c) The brick of specimen E after 28

days of curing (d) The brick of specimen A after 28

days of curing.

The lesser the content of the gold tailings used, the less likely the paper-pulp was able to blend

with the tailings. That is evident on figure 7(a) and figure 6(b) as these bricks do not have

defined and sharp edges and their surface is irregular and uneven as opposed to figure 7(d)

0123456789

Un

con

fin

ed C

om

pre

ssiv

e st

ren

gth

(MP

a)

Specimen cured for 28 days

from specimen A. The bricks were 50 x 50 x 50 mm3, with the final weight ranging between

102 -112 g.

3.3 The Unconfined compressive strength with varied curing age and the weight of the

specimen

The strength development on the specimen formed from specimen A, the optimum mix design

with varying curing age to investigate how the curing age affects this type of papercrete bricks

was studied. The results obtained are presented in Figure 8. An increase in the curing age

resulted into the increase in the UCS. The brick cured for 28 days has the highest UCS value

of 7.76 MPa whereas the brick cured for 7 days has a UCS value of 2.16 MPa. This shows a

decrease in the UCS of 72.2%, respectively, when the curing age was increased from 7 to 28

days.

Figure 7. The effect of curing age on the

compressive strength of the specimen

Figure 9. The effect of curing age on the weight of

the specimen

Paper dries faster hence it was expected that the tailings would have been dry in 7 days however

due to the incorporation of gold tailings into the mix design, the specimen took longer to dry.

This could be attributed to the sufficient moisture that is available for continued hydration of

the gold tailings in the papercrete as reported by Neville and Brooks (1987). The papercrete

were able to achieve the targeted minimum strength of 3.5 MPa at 14, 21 and 28-days compared

to the same papercrete specimen cured for 7 days. The same papercrete specimen cured for 7

days had a compressive strength of 2.16 MPa.

The minimum Compressive Strength of a brick is 3.5 N/mm2 (Civil-Seek, 2017). All the bricks

from specimen A are suitable for use for building purposes except for the brick cured for 7

days. Further analysis was not done on it since it is not suitable for construction purposes.

The brick cured for 7 days had the lowest compressive strength, this was expected as the

minimum time from which sun-dried bricks are cured is 28 days and as the brick is still moist.

It was also discovered that the lesser the tailings were used in the specimens, the more fragile

the bricks were. That is a result of the insufficient quantity of the source of lime and silica in

the tailings to form silicates and aluminates of calcium. Deficiency in lime reduces the strength

property of the tailings and it causes the tailings to set quickly. The faster the tailings set, the

weaker are the bricks. (Civil-Seek, 2017).

All the bricks of specimen A were weighed after different curing days to see the effect the

drying time had on their weight and how that compares to the conventional clay bricks. The

0

1

2

3

4

5

6

7

8

9

10

7 Days 14 Days 21 Days 28 Days

Un

con

fin

ed c

om

pre

ssiv

e st

ren

gth

(MP

a)

Curing age ( Days)

62

64

66

68

70

72

74

14 Days 21 Days 28 Days

Wei

gh

t(g)

curing age (days)

ordinary conventional clay bricks weight varies from 3 – 4 kg (Arya and Kansa, 2013. In this

study the papercrete bricks weight, for the optimum bricks varied from 67.193-71.522g, Figure

8. This shows that the bricks are extremely light, weighing 56% less than the conventional

cement brick.

3.4. Water absorption tests

The highest water absorption for the specimen when immersed in water for 24-hours, Figure

10. The highest water absorption was from the 14-day specimen with a percentage of 98.89%

and the lowest being from the 28-day specimen at 80.43%. All the bricks have the highest water

absorption, which is non-compliant to the international standards that specifies that the bricks

should not absorb more than 20% water. Paper is the main constituent of papercrete and so its

properties depend on the paper’s microstructure. Paper is a completely water-absorbable

material hence the high absorption percentages. Thus, the ability of water to penetrate the

papercrete structure is a property both highly significant to the use of paper.

Figure 10. water absorption results for different

curing days.

Figure 11. (a) 14th day cured brick after absorption

(b) 28 days cured brick after absorption test.

3.5 Fourier Transform-Infrared Spectroscopy (FTIR)

FTIR analytical technique was used to identify whether the gold tailings are organic or

inorganic and the type of functional group present in the tailings. This technique measured the

absorption of infrared radiation by the sample material versus wavelengths that are present in

the gold tailings. This method was considered useful in order to avoid any reaction that might

affect the samples composition or structure during the sample preparation. The major

absorption peaks obtained from the spectrum are given in Table 2 and these are identified with

the functional groups that are responsible for the different modes of vibrations.

Table 2. Infrared characteristic modes of vibrations and their wavenumbers for the Gold tailings

Wavenumbers (cm-1) Functional Groups in the Gold tailings

3742.63 O-H

3619 O-H STRETCH

2357.56 Si-H Silane

1623.3 Si-OR

1446.17 Sulfate S=O

987.4 N-O Oxidized

786.05 S-OR ester

0

20

40

60

80

100

120

140

160

14 Days 21 Days 28 Days

wat

er a

bso

rbed

(%

)

683.66

Table 3: Oxide composition of ordinary Portland cement (Arya and Kansa, 2013)

Common Name Oxide Abbreviation Approximate

composition limits (%)

Lime CaO C 60-66

Silica SiO2 S 19-25

Alumina Al2O3 A 3-8

Iron Oxide Fe2O3 F 1-5

Magnesia MgO M 0-5

Alkalies:

Soda Na2O N 0.5-1

Potassa K2O K 0.5-1

Sulphur trioxide SO3 S 1-3

Table 3 shows all the oxides and the maximum ASTM percentage limits of cement against the

mass percentages of the elements in the tailings. The results show that the percentages of all

compounds present in the tailings comply to the ASTM standards except the mass percent of

Al2O3, Fe2O3 and SO3 which exceed the ASTM specifications. There were four dominant metal

oxides present in the tailings, namely SiO2, Fe2O3, Al2O3 and CaO. Silica (SiO2).

Materials used for Portland cement production must contain, in proper form and proportions,

lime, silica and alumina. The raw materials used in the manufacture of Portland cement consist

mainly of lime, silica, alumina and iron oxide.

Cement comprises of high concentration of oxides as shown in table which amount to over

90% with CaO being the main oxide followed by SiO2. However, the results on Table 2 shows

the reverse values as the mass percentage by mass of CaO is lesser than that of SiO2. The ratio

of CaO to silica for cement is 3:1 but 1:5 for the gold tailings. This has various disadvantages

as the rate of hardening of any binding material used to substitute cement depends on its

chemical and physical properties and the curing conditions. (Ridi, 2010)

3.6 XRF of the bricks for the 14-, 21- and 28-day optimum bricks

The XRF analysis shows the major elements that the gold mine tailings consist of and the

elements after gold tailings was blended with paper pulp, Figure 12.

Figure 12: The elemental composition of the composite with different curing period

There was a slight change in the relative proportion of the constituents with curing. However,

the predominant constituents in terms of weight percent remained the same as was discovered

in the raw gold tailing, as SiO2 was the dominant component, followed by Fe2O3 and Al2O3.

There is a variation in the composition of Fe2O3 with curing. The relative proportion of silica

increased with increasing number of curing days. There was no significant change in other

constituent as the specimen were cured for longer period.

3.7 Scanning Electron Microscopy (SEM)

A quantitative analysis on the morphology of the raw gold tailings and tailings with the pulp

was performed using a scanning electron microscope for 7, 14 and 28 days curing period. The

results obtained are presented in Figures 13-16.

Figure 13: SEM of raw GMT Figure 14: SEM of GMT:Pulp 14 days curing

Figure 15: SEM of GMT:Pulp 21 days curing Figure 16: SEM of GMT:Pulp 28 days curing

0.00

10.00

20.00

30.00

40.00

50.00

60.00

MgO Na20 K2O Al2O3 Fe2O3 CaO SiO2 SO3

wt

(%)

Raw tailings Drying Period 14 days

Drying Period 21 days Drying Period 28 days

a) Raw gold tailings b) 7 days curing

c) 14 days curing d) 28 days curing

The SEM micrograph shows that the raw gold tailings had non-spherical particles, with

pervasive tiny voids and flaky irregular shape, indicating the tailings are less stiff. The raw

gold tailings grains are poly-phased and not mono-phased since they have different shapes.

Finely ground powders like cement have the important property that when mixed with water a

chemical reaction (hydration) takes place. Hydration produces a very hard and strong binding

medium for the aggregate particles, (Ridi, 2010). There was a change in the morphology of the

tailings:pulp specimen over the curing period of 7, 14 and 28 days. In the 7 specimen cured for

7 days, the particles are binding together and beginning to form small spherical particles. For

the specimen cured for 14 and 28 days, there is a clear indication that the particles compared

to the raw and specimen cured for 7 days.

3.8 Environmental impact

There are no harmful by-products or excessive energy used in the production of papercrete.

Paper fibers hold the gold tailings. Papercrete can be produced using solar energy. The only

power needed is for mixing and pumping water. The most important benefit of papercrete is

the reduction of cement in the mix. Carbon emissions, the total cost and weight are drastically

reduced, resulting in a cheap and lightweight material. Paper fibers result in excellent heat and

sound-insulating properties. Papercrete motivates recycling of waste paper, especially in

communities with no recycling services. It divert both waste paper and gold tailings from the

landfill and introduces new building material.

Conclusion

The voluminous waste generated by the gold mining industry in the form of gold tailings and

waste paper, calls for urgent innovative solutions to use the wastes. In the study it was proven

that there is a great potential for wastes such as paper and gold tailings to be blended together

to produce value added material such as papercrete. In respect to unconfined compressive

strength shown by the tested bricks, the bricks can be used as a lightweight building material.

The strength up to 7.76 MPa was achieved, showing that the developed papercrete is also

applicable as a load bearing material, as the minimum strength required for load bearing is 3.5

MPa. High content of gold tailings and paper waste up to 45% and 55% can be blended

successfully to produce high strength papercrete. This will solve the environmental and

environmental pollution challenges related to these two wastes.

Although the bricks are suitable for use as a building material (in respect to the developed

strength), they are ultimate for non-load bearing walls only. The maximum acceptable water

absorption for bricks to be used for load bearing is 20%. The water absorption capacity of

papercrete bricks was found to be more than 20%, which makes them unsuitable for water

saturated areas and external walls. These bricks are also ideal material for earth quake prone

areas due to their lightweight. The use of gold tailings is marginalized costly than the use of

cement. The gold tailings has a potential to be used and completely replace cement in the

papercrete. Waterproofing admixtures should be used as one of the additives in papercrete mix

or on the final developed bricks to prevent high water absorption. Material such as polystyrene

and plastic can be incorporated into the mix design, to reduce the water absorption. With

modification of the water absorption capacity of the papercrete, the developed material can be

used successfully to address the human settlement challenge in South Africa, by providing low

cost housing building material.

Acknowledgement

The author would like to thank the University of Johannesburg for providing the resources to

conduct the project and National Research Foundation for funding.

References

Arya, R.K. and Kansa, R. (2013). Utilization of waste papers to produce eco-friendly bricks.

International Journal of Science and Research , 2319-7064.

ASTM C856-14., (2013). Standard Test Method for Petrographic Examination of Hardened Concrete.

In A. B. Standards, American Society, 2-4.

Breytenbach, M. (2016, October 14). Gold tailings retreatment an attractive. Retrieved from

miningweekly: http://www.miningweekly.com/print-version/south-africa-has-absolute-potential-for-

vibrant-sustainable-tailings-projects-industry-players-2016-10-14.

Civil-Seek. (2017). Test for Compressive Strength of Bricks, Absorption, Efflorescence and Size.

Retrieved from Civil Seek : The home for civil Engineers.

Fall, M., Célestin, J.C., Pokharel, M. and Touré, M. (2010). A contribution to understanding the effects

of curing temperature on the mechanical properties of mine cemented tailings backfill. Engineering

geology, 114, 397-413.

Gorgis, I.N., Zaki, H.M. and Salih, S.A., 2006. Properties of Papercrete.

Koroneos, C. and Dompros, A., (2007). Environmental assessment of brick production in Greece.

Building and Environment, 42(5), 2114-2123.

Kunt, K., Yıldırım, M., Dur, F., Derun, E., and Pişkin, S. (2015). Utilization of Bergama Gold Tailings

as an Additive in the Mortar. Celal Bayar Üniversitesi Fen Bilimleri Dergisi, 11(3), 365-371.

Maheshwari, M. K. (2017). Papercrete. International Journal of Science, Engineering and Technology

Research (IJSETR), 1289-1297.

Mashifana, T., Okonta, F.N. and Ntuli, F. (2018). Geotechnical properties and application of lime

modified phosphogypsum waste. Materials Science, 24(3), 312-318.

Michael-Chusid, S. H., (2009). The building bricks of sustainability. The construction specifier, 1, 30-

40.

Neville, A.M. and Brooks, J.J. (1987). Concrete Technology . England: Longman Scientific &

Technical, 242-246.

Patterson. E. and McCain. M., http://www.greenhomebuilding.com/articles/papercrete.htm.

Ridi, F. (2010). HYydration of cement:Still a lot to understand. CRITICAL REVIEWS, 110-117.

Scinduja, M. and Nathiya, S., 2014. Innovative brick material using waste paper. International Journal

for Research in Applied Science and Engineering Technology Special Issue-1.

Shermale, Y.D. and Varma, M., 2016. Properties of Papercrete Concrete: Building Material. IOSR

Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN, 2278-1684.

Shermale, Y.D. and Varma, M.B. (2015). Papercrete: an efficient use of waste paper. Recent Trends

Civil Engineering and Technology, 5(03), 54-59.

Toledo, D. R. (2004). Gas release during clay firing and evolution of ceramic properties. Applied Clay

Science, 27, 151-157.

Vermeulen, N.J. (2001). The composition and state of gold tailings. University of Pretoria,

Pretoria.

Writer, S. (2018). These are the biggest gold producing countries in the world. Retrieved from Business

Tech.