COMTRADE Data for Ghana
COMTRADE data can indeed be found for Ghana. You can see that the cartograms on this website show data for Ghana. See http://scalar.usc.edu/works/reassembling-rubbish/visualizing-transboundary-shipments-of-e-waste . If you 'zoom in' after opening the cartograms you will be able to locate Ghana and see that trade transaction data for 1996 and 2012 are there.
COMTRADE has rejigged their website since I downloaded data from it. I suggest selecting what the site calls the "Legacy Annual" and retrying your data query. Here are the steps I followed when I originally downloaded the data some years ago:
Go to the UN COMTRADE website and select "Legacy Annual". Then:
1. Go to “Data Query” and select “Basic Selection”
2. Under the “Commodities” menu, input HS code: 854810 (waste and scrap of primary batteries and electrical accumulators)
3. Click “Add” and then “Submit Query”
4. At this point you will be offered a menu to select “Trade Flow” (import or export), Partner (this is the list of countries), and year. Select the variables you want.
5. Click “Direct Download”. This will download a .csv file. Open the file in a spreadsheet program.