Properties of tungsten mine waste geopolymeric binder

Mix proportion and strength testing

In this investigation the mortar was a mixture of aggregates, waste mud, calcium hydroxide, alkaline silicate solution and water. The mass ratio of mine waste mud: activator was 1:1. Calcium hydroxide was used with a percentage substitution of 10%, because it was found that percentage lead to the highest compressive strengths. An activator with sodium hydroxide (24 M) and sodium silicate solution (Na₂O = 8.6%, SiO₂ = 27.8%, Al₂O₃ = 0.4% and water = 63.2%) was used with a mass ratio of 1:2.5. Previous investigations showed that this ratio lead to the highest compressive strength results in alkali-activated mine waste mud mortars. Distilled water was used to dissolve the sodium hydroxide flakes to avoid the effect of unknown contaminants in the mixing water. The alkaline activator was prepared prior to use. The sand, mine waste mud and calcium hydroxide were dry mixed before added to the activator, which according to Pinto et al. is the mixing option that leads to the best results. To produce a workable mix extra water has been added as stated by Jahanian and Rostami. The mass ratio of water/ dry solid binder content was 3.6% in most of the samples, except for samples with an aggregate/binder mass ratio of 1.5 or 1.7. In those cases, the extra water percentages were respectively 7 and 10% . TMWM binders using schist (SC) fine aggregates with an aggregate/binder ratio of 1.5 were named SC – AG/B 1.5. Similarly when limestone (LS) or granite (GR) aggregates were used were named respectively LS – AG/B 1.5 and GR – AG/B 1.5. TMWM mixtures made with 2% superplasticizer by mass of binder lime and mine waste mud, were named respectively SC/SP, GR/SP and LS/SP.

Compressive strength data was obtained using 50x50x50 mm3 cubic specimens according to ASTM C109 . The fresh mortar was cast and allowed to set at room temperature for 24 h before being removed from the moulds and kept at room temperature until tested in compression. Compressive strength for each mixture was obtained from an average of three specimens.

 

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Properties of tungsten mine waste geopolymeric binder

Experimental work

Materials

Mine waste Blaine fineness is low but is in the range of the most used slag based alkaline binders. Despite the fact that increase fineness led to increase reactivity that can be overcome by using higly alkaline-silicate activators.

Table 2 shows gradation and physical characteristics of aggregates. Limestone and granitic coarse aggregates have the same Faury maximum dimension (9.52) and similar fineness modulus respectively 5.5 and 5.2. Schist sand has a lower maximum dimension (2.78) and a fineness modulus of 2.38.

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How to run tungsten darts league? Some do it all at the beginning, while others put off parts of the process until forced to. Over a period of years, all of these topics will eventually have to be addressed, one way or another.

(This article is based on the Editor's more than 39 years of experience with tungsten dart leagues in the USA. Most of the topics will apply anywhere, but some details may vary in other countries.)

Name the Organization. This may include a designation such as League, Club, Association, Organization, Federation, etc. It should be unique, not the same or similar enough to confuse with any other entity. Make it short enough to say easily aloud, and to fit a letterhead. It won't hurt if abbreviations and the initials are catchy and don't make any obscene acronym. Think about how the name will look as a domain name, and check on whether that domain name might be available.

Type of League. Will this be a "Trophy" tungsten darts league, or a "Money" tungsten darts league? In the USA, many or most soft-tip leagues seem to play for monetary prizes, while the majority of steel-tip leagues appear to play for trophies. Keep in mind that whenever money becomes involved in competition, the likelihood of arguments is greatly increased. As with marriages, arguing over money is one of the chief causes of failed leagues.

Organizational structure. If money is going to be collected for dues or awards, it is a very good idea to formalize a legal structure for the group. This may be setup as a business, a partnership, corporation, or non-profit entity. Different states & countries will have different options available, as well as legal requirements to meet. In the USA, many leagues organize as Not-For Profit Corporations, to reduce both personal and tax liability. Elect officers as needed to run the league, and as may be required by law for the type of organization.

Officers. How many will be needed, and their positions. This can be a complex issue, as personalities often come into play. A new group will nearly always underestimate the amount of work needed to run a tungsten dart league. And, no matter how many officers are elected, it is simple fact that just 3 or 4 people will probably end up doing at least 80% of the work. The legal status of the league may dictate a certain minimum number of officers, as well as their responsibilities. Keep in mind that the in the eyes of the law, the President and Treasurer of an Incorporated tungsten darts organization may be legally quite similar, for example, to the corporate officers of Enron Corporation. Take the legal responsibilities seriously!

Attorney. This is one of the most commonly skipped steps. Unfortunately, not getting legal guidance at the beginning can lead to incredibly messy problems in the future. Ask around among the darts players. Many organizations have a member in the legal profession, who will volunteer services, or at least offer a discount. Lawyers are constantly called on to help setup new businesses and organizations, and will greatly ease the process of starting up the new league.

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Accounting. Consult an Accountant! This step is also commonly skipped, and is a leading cause of small organizations failing. The accountant, or CPA (Certified Public Accountant) , can provide a list of the steps needed to deal with banks and tax authorities. The CPA will also help the organization setup a proper bookkeeping system. This can greatly reduce the ulcer rate among officers who might eventually find themselves opening extremely intimidating letters from the tax man.

Rules. Will the league write its own rules, or follow the rules of another league or sanctioning body?

Business licenses. Most of these may, or may not, have been taken care of when the legal structure of the organization was setup. Assumed Name Permit, Tax Permit or Tax Exempt Certification, Business Operation Permit, etc. Check at the local courthouse to determine what is needed.

Bank Account. To get a checking account, the new tungsten darts association or league will have to provide certain documentation to the bank. This generally includes proof that the organization is legally registered in one form or another, and may also require proof of registration with the appropriate tax authorities. A minimum starting deposit is usually required, in the USA that often is in the range of $100 to $500. It is important that bank accounts be setup so that two officer's signatures are required to write checks or make withdrawals. While everyone may start out as bosom buddies, nothing can sour friendships and destroy a league as quickly as money going missing. In some cases, malfeasance can (and has) led to lawsuits, or even arrests of league officers. Having two signatures on every check is simply good policy.

Printing. Checks and deposit slips have to be ordered. Membership applications and advertising brochures, flyers, posters, business cards, etc. all need to be designed and printed. Score sheets or match report forms will be needed, and maybe envelopes or postcards for notices. Large envelopes or binders will be needed for team captains to carry their paperwork.

Awards. While trophies and certificates may not be needed until the first season ends in a few months, a quote on the cost of producing the awards is needed immediately, so that a budget can be setup. Decisions will have to be made as to the type of awards, and how many people or teams will receive them.

Budget. Following the Awards topic above, a budget must be setup, and quotes for all expenses are needed in order to do that. Once all expenses have been added up, the tungsten dart league can determine how much income must be generated each season & year. From there, calculate how much to charge for dues, team fees, bar fees, etc.

Bonding. This should probably be fit in somewhere among topics of Officers, Legal, and Accounting. "Bonding" means purchasing a type of insurance call a Bond, which insures against malfeasance or legal charges against key officers. If, for instance, the Treasurer suddenly relocates out-of-town, and the bank account seems much smaller that it should be, this insurance might cover the missing funds. Officers must generally pass a background check for criminal history, which is not a bad idea for people who will be handling a lot of money belonging to someone else. After all, how well do you really know that nice fellow you met in a bar a couple of weeks ago, and who recently volunteered to take care of the checkbook for you?
 

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